Isolated male epispadias typically presents with preputial defects and dorsal urethral dehiscence. A less common subtype, known as concealed epispadias, is distinguished by an intact prepuce. Despite its clinical rele...Isolated male epispadias typically presents with preputial defects and dorsal urethral dehiscence. A less common subtype, known as concealed epispadias, is distinguished by an intact prepuce. Despite its clinical relevance, there is limited literature on this variant. In this study, we retrospectively analyzed the clinical data of 86 pediatric patients with isolated male epispadias treated in Beijing Children’s Hospital (Beijing, China) from May 2004 to July 2023, including 19 cases of concealed epispadias and 67 of nonconcealed epispadias. We compared clinical characteristics, preoperative diagnostics, surgical techniques, postoperative outcomes, and sexual function during follow-up between the concealed and nonconcealed groups. No significant differences were observed between the two groups regarding surgical methods, postoperative complications, or rates of urinary incontinence. However, notable distinctions were found in the age at initial diagnosis, timing of surgery, frequency of incontinence, location of the urethral meatus, and postoperative urinary incontinence scores (all P < 0.05). Given the absence of penopubic epispadias in concealed cases, we categorized glans and penile epispadias within nonconcealed epispadias as distal epispadias (n = 40) and subsequently compared them with concealed epispadias cases. The postoperative urinary incontinence scores did not differ significantly between the concealed and distal epispadias groups. These findings suggest that concealed epispadias represents a relatively milder form of the condition, characterized by the absence of penopubic involvement, lower rates of urinary incontinence, and favorable surgical outcomes. However, the intact prepuce in concealed cases underscores the need for careful identification and early diagnosis.展开更多
Blockchain,as a distributed ledger,inherently possesses tamper-resistant capabilities,creating a natural channel for covert communication.However,the immutable nature of data storage might introduce challenges to comm...Blockchain,as a distributed ledger,inherently possesses tamper-resistant capabilities,creating a natural channel for covert communication.However,the immutable nature of data storage might introduce challenges to communication security.This study introduces a blockchain-based covert communication model utilizing dynamic Base-K encoding.The proposed encoding scheme utilizes the input address sequence to determine K to encode the secret message and determines the order of transactions based on K,thus ensuring effective concealment of the message.The dynamic encoding parameters enhance flexibility and address issues related to identical transaction amounts for the same secret message.Experimental results demonstrate that the proposed method maintains smooth communication and low susceptibility to tampering,achieving commendable concealment and embedding rates.展开更多
Mineral exploration under exotic overburden has been a great challenge in exploration geochemistry.Gas geochemical measurement is a potential method for mineral exploration due to the characteristics of strong penetra...Mineral exploration under exotic overburden has been a great challenge in exploration geochemistry.Gas geochemical measurement is a potential method for mineral exploration due to the characteristics of strong penetrability and vertical migration.The previous rapid gas analyzer cannot determine low concentrations of soil gases because of inadequate sensitivity,therefore,it is necessary to develop a more sensitive analytical technique.In this paper,the pilot studies on CO_(2) and SO_(2) geochemical measurements were performed at the Zhuxi W-(Cu)deposit,Jiapigou gold ore-concentrated area,and Tukuzbay gold deposit.This study employed rapid gas analyzer based on Infrared Absorption Spectroscopy and Electrochemical Analysis,which can detect low concentrations of CO_(2) and SO_(2) and greatly improve the reliability of test data.The results show that CO_(2) and SO_(2) show clear anomalies over deeply concealed ore bodies and faults,demonstrating that CO_(2) and SO_(2) anomalies can reveal indicative information about concealed mineralization and faults.Moreover,CO_(2) and SO_(2) anomalies can identify mineralization information exceeding 1,000 m in depth,suggesting that this method has large detection depth.Therefore,CO_(2) and SO_(2) geochemical measurement method is a feasible tool to discern deeply concealed mineralization and faults,and can provide a new idea in prospecting for concealed ore deposits in covered areas.展开更多
Actuator dynamics introduce a synchronization disparity between commanded displacements transmitted to the actuator and the actual displacements generated by the actuator,thereby affecting its precision and potentiall...Actuator dynamics introduce a synchronization disparity between commanded displacements transmitted to the actuator and the actual displacements generated by the actuator,thereby affecting its precision and potentially leading to instability in real-time hybrid simulation(RTHS).This study aims to elucidate the relationship between calculated and measured displacements by analyzing their magnitude and phase in the frequency domain via transformations.The physical implications of these relationships are explored in the context of frequency domain evaluation indices(FEI),the transfer function of actuator dynamics,and delay compensation.Formulations for achieving perfect compensation of actuator dynamics are developed,and an enhanced compensation approach,termed improved windowed frequency domain evaluation index-based compensation(IWFEI),is introduced.The efficacy of IWFEI is assessed using a RTHS benchmark model,with perturbed simulations conducted to validate its robustness.Uncertainties inherent in actuator dynamics are represented as random variables in these simulations.Comparative analysis of the mean values and variances of evaluation criteria demonstrates that IWFEI enables more accurate and robust compensation.Furthermore,strong correlations observed among criteria in the time and frequency domains underscore the effectiveness of the proposed frequency domain-based compensation method in mitigating amplitude errors and phase delays in RTHS.展开更多
Structures modelled with flexible-base assumptions,incorporating soil effects,generally exhibit longer natural periods and higher damping compared to fixed-base models that exclude soil-structure interaction(SSI).Howe...Structures modelled with flexible-base assumptions,incorporating soil effects,generally exhibit longer natural periods and higher damping compared to fixed-base models that exclude soil-structure interaction(SSI).However,the beneficial or detrimental nature of SSI remains contentious in current earthquake damage analyses and research findings.This study introduces a numerical modelling technique,validated by experimental shaking table tests,to examine the effects of SSI on high-rise buildings.The study considers various substructure parameters,including foundation types,soil types,and bedrock depths.Both advantageous and adverse impacts of SSI are identified and analysed.Numerical simulations reveal that increased subsoil stiffness significantly amplifies the base shear of structures compared to bedrock depth effects.Additionally,increased foundation rocking results in higher inter-storey drifts and reduced base shear.Overall,SSI tends to amplify inter-storey drifts,indicating detrimental effects.Specifically,the study found that the inclusion of SSI increased maximum inter-storey drifts by up to 38%,particularly in softer soils,while reducing base shear by up to 44%in structures with classical compensated foundations on D_(e)and E_(e)soil types.In contrast,piled foundation systems experienced an increase in base shear of up to 27%under the same conditions.Conversely,SSI has beneficial impacts on base shear for structures with classical compensated foundations on soil types of D_(e)and E_(e),as it reduces the base shear.For structures with piled foundations and those with classical compensated foundations on C_(e)soil,SSI effects are detrimental.C_(e),D_(e),and E_(e)soils correspond to geotechnical classifications per AS1170,representing stiff,medium,and soft soils respectively.The study also presents minimum base shear ratios considering SSI reduction effects for various foundation types.展开更多
Due to the influence of karst cave development and route selection,the location relationship between concealed karst cave and tunnel is more random.In order to explore the influence rule of karst cave location on the ...Due to the influence of karst cave development and route selection,the location relationship between concealed karst cave and tunnel is more random.In order to explore the influence rule of karst cave location on the minimum safe thickness of water-proof rock mass,a simplified calculation model of water-proof rock mass thickness when the karst cave is located at any location around the tunnel is established,and the influence of multiple factors on the overall stability of water-proof rock mass is considered.Based on the cusp catastrophe theory,the analytical expressions for the safety thickness of waterproof rock mass are derived.Based on the finite difference principle,the analytical expressions of the safety thickness of water-proof rock mass are verified.In order to improve the application range of the analytical formula derived in this paper,the analytical formula is optimized based on the instability principle differences between the simplified calculation model and the elastic compressive bar.The research results show that the necessary condition solution is more applicable and much safer than the sufficient condition solution.Tectonic stress,rock beam length and karst cave water pressure are significantly positively correlated with the safe thickness of the waterproof rock mass.The calculated results of the semioptimized formula and the unoptimized formula are constant values,independent of the karst cave location.While the calculated results of the fully optimized formula are variable values,correlated with the karst cave location,the thickness of the waterproof rock mass gradually decreases as the karst cave location moves from the top of the tunnel to the bottom of the tunnel.The unoptimized formula does not consider the influence of the lateral force of the rock beam,and is not suitable for the working condition with large lateral force,the calculation results of the semi-optimized formula and the fully optimized formula are not very different and are biased to safety,so it can be given priority.展开更多
In the construction of shallow-buried concealed tunnels,the control of surrounding rock stability is a core challenge,which is crucial to construction safety and structural performance.A two-dimensional model was esta...In the construction of shallow-buried concealed tunnels,the control of surrounding rock stability is a core challenge,which is crucial to construction safety and structural performance.A two-dimensional model was established using Midas GTS NX,combined with bench cut method excavation simulation.The laws of vault and surface settlement were quantitatively analyzed through displacement nephograms,and the spatiotemporal characteristics of surrounding rock displacement were revealed.The results show that under the established excavation and support measures,the displacement and settlement meet the specification requirements.Meanwhile,the Analytic Hierarchy Process(AHP)was introduced to determine weights and analyze the coupling correlation of factors through judgment matrices,clarifying the influence degrees of surrounding rock grade,support strength,and other factors to achieve multi-dimensional evaluation.Furthermore,the Fuzzy Comprehensive Evaluation method was integrated to quantify the mapping relationship between surrounding rock stability and safety,and the safety grade was obtained.Finally,measures such as strengthening support,optimizing excavation parameters,refined exploration,and improving management were proposed to enhance surrounding rock stability and reduce construction risks.展开更多
To evaluate the therapeutic effect of a modified Devine procedure with a subcutaneous sliding fixation method for the treatment of congenital concealed penis,we retrospectively selected 45 patients with congenital con...To evaluate the therapeutic effect of a modified Devine procedure with a subcutaneous sliding fixation method for the treatment of congenital concealed penis,we retrospectively selected 45 patients with congenital concealed penises who were admitted to General Hospital of Ningxia Medical University(Yinchuan,China)between September 2020 and November 2023.In all cases,the penis was observed to be short,and retracting the skin at the base revealed a normal penile body,which immediately returned to its original position upon release.All patients underwent the modified Devine procedure with subcutaneous sliding fixation and completed a 12-week postoperative follow-up.A statistically significant increase in penile length was observed postoperatively,with the median length increasing from 4.0(interquartile range[IQR]:3.5–4.8;95%confidence interval[CI]:3.9–4.4)cm to 8.0(IQR:7.8–8.0;95%CI:7.7–7.9)cm,with P<0.001.The parents were satisfied with the outcomes,including increased penile length,improved hygiene,and enhanced esthetics.Except for mild foreskin edema in all cases,no complications(such as infections,skin necrosis,or penile retraction)were observed.The edema was resolved within 4 weeks after the operation.This study demonstrates that the modified Devine procedure utilizing the subcutaneous sliding fixation method yields excellent outcomes with minimal postoperative complications,reduced penile retraction,and high satisfaction rates among patients and their families.展开更多
The identification and characterization of concealed in-situ rock blocks on high-steep slope exposures are critical in rock engineering,but remain challenging.This study employs advanced UAV-based photogrammetry to ca...The identification and characterization of concealed in-situ rock blocks on high-steep slope exposures are critical in rock engineering,but remain challenging.This study employs advanced UAV-based photogrammetry to capture high-resolution discontinuity data and develops a fully automated rock block extraction method consisting of three steps:(1)determination of free face and non-free fracture intersections,(2)surface search for rock blocks on free face.and(3)extraction and analysis of rock blocks.This approach simplifies the determination of discontinuity intersections while maintaining high accuracy.By incorporating all types of discontinuities contributing to rock block formation,the method enables precise in-situ rock block identification and extraction.Application to a rock slope in China,produced results consistent with the rock blocks observed in the 3D model,highlighting its accuracy and practical value.展开更多
Deep neural network has proven to be very effective in computer vision fields.Deep convolutional network can learn the most suitable features of certain images without specific measure functions and outperform lots of...Deep neural network has proven to be very effective in computer vision fields.Deep convolutional network can learn the most suitable features of certain images without specific measure functions and outperform lots of traditional image processing methods.Generative adversarial network(GAN)is becoming one of the highlights among these deep neural networks.GAN is capable of generating realistic images which are imperceptible to the human vision system so that the generated images can be directly used as intermediate medium for many tasks.One promising application of using GAN generated images would be image concealing which requires the embedded image looks like not being tampered to human vision system and also undetectable to most analyzers.Texture synthesizing has drawn lots of attention in computer vision field and is used for image concealing in steganography and watermark.The traditional methods which use synthesized textures for information hiding mainly select features and mathematic functions by human metrics and usually have a low embedding rate.This paper takes advantage of the generative network and proposes an approach for synthesizing complex texture-like image of arbitrary size using a modified deep convolutional generative adversarial network(DCGAN),and then demonstrates the feasibility of embedding another image inside the generated texture while the difference between the two images is nearly invisible to the human eyes.展开更多
In this paper, a new method of time reversal for defect diagnosis of concealed structure has been proposed based on the detecting technique of structure acoustic wave and the theory of time reversal. The time reversal...In this paper, a new method of time reversal for defect diagnosis of concealed structure has been proposed based on the detecting technique of structure acoustic wave and the theory of time reversal. The time reversal recurrence formula for detecting the acoustic wave speed constitution of concealed structures with bilevel asynchronous test has been established. The wave speed constitution can be reconstructed in 2 D graticule form by means of this method. The result of model test shows the method is valid.展开更多
Since real world communication channels are not error free, the coded data transmitted on them may be corrupted, and block based image coding systems are vulnerable to transmission impairment. So the best neighborh...Since real world communication channels are not error free, the coded data transmitted on them may be corrupted, and block based image coding systems are vulnerable to transmission impairment. So the best neighborhood match method using genetic algorithm is used to conceal the error blocks. Experimental results show that the searching space can be greatly reduced by using genetic algorithm compared with exhaustive searching method, and good image quality is achieved. The peak signal noise ratios(PSNRs) of the restored images are increased greatly.展开更多
With the rural concealed communication cable as the study object, the shielding effectiveness of different slot shapes was analyzed by using LBEM （linear boundary element method）. The engineering example results sho...With the rural concealed communication cable as the study object, the shielding effectiveness of different slot shapes was analyzed by using LBEM （linear boundary element method）. The engineering example results showed that for twocore shielded cable, the coupling capacitance of trapezoid slots （asymmetric and symmetric） changed the most, followed by rectangular slots （asymmetric and symmetric）, and the changes of wedge slots were the smallest, but the change tenden- cies were consistent. In addition, with the increase of slot width of different slots, the coupling capacitance of tow-cored shielded cable showed small change.展开更多
Objective:To explore the relationship between cancer awareness and the survival of the patients with non-small cell lung carcinoma(NSCLC).Methods:A total of 865 NSCLC patients were screened for the risk factors,includ...Objective:To explore the relationship between cancer awareness and the survival of the patients with non-small cell lung carcinoma(NSCLC).Methods:A total of 865 NSCLC patients were screened for the risk factors,including age,gender,address,tumor/lymph nodes/metastasis(TNM)stage,and cancer awareness.Survival of the patients was calculated by Kaplan-Meier method and Cox regression analysis.Results:After an average observation time of 304 d(ranging from 0 to 4718 d),62 of the 394 patients in the cancer awareness group survived,whereas 26 of the 471 patients in the cancer concealment group survived.Cancer-specific and all-cause survival was poorer in the cancer concealment group(P<0.001 for each,log-rank test).Cox multivariate regression analysis showed that cancer concealment displayed significantly lower cancer-specific survival[hazard ratio(HR)=1.534,95%con fi dence interval(CI)1.320 to 1.784,P<0.001]and all-cause survival(HR=1.558,95%CI 1.346 to 1.803,P<0.001).Conclusion:Cancer concealment is associated with a poor survival of NSCLC patients,which may prohibit the patients from obtaining the real“right to survival”.展开更多
A successful case history of exploring for concealed structure using the high-resolution EM method in the investigation of the West-East Gas Pipeline Project＇s B Tunnel is presented in this paper. The high frequency ...A successful case history of exploring for concealed structure using the high-resolution EM method in the investigation of the West-East Gas Pipeline Project＇s B Tunnel is presented in this paper. The high frequency electromagnetic image system named STRATAGEM EH4, operating at frequencies ranging from 90KHz to 1Hz, was used for data acquisition. The orthogonal components of the electromagnetic field were measured during the field acquisition and the relevant electromagnetic attributes of the object body were extracted from the electromagnetic data. Hybrid sources, consisting of natural and full tensor-controlled sources, were utilized to produce high-quality electromagnetic field data. B Tunnel lies in the western part of Hubei province, at depths of less than 200m. The geologic setting of B tunnel is very complex. Following an initial geologic investigation, an outcrop considered to be a bedrock interface by investigators, collapsed during tunneling operations. A second investigation applied high-resolution EM and seismic refraction methods to reveal a more complex geologic structure along the tunnel route. The predicted rock classes and fault were encountered during the subsequent tunneling operations.展开更多
An attribute recognition model for safe thickness assessment between a concealed karst cave and a tunnel is established based on the attribute mathematic theory.The model can be applied to carrying out risk classifica...An attribute recognition model for safe thickness assessment between a concealed karst cave and a tunnel is established based on the attribute mathematic theory.The model can be applied to carrying out risk classification of the safe thickness between a concealed karst cave and a tunnel and to guarantee construction’s safety in tunnel engineering.Firstly,the assessment indicators and classification standard of safe thickness between a concealed karst cave and a tunnel are studied based on the perturbation method.Then some attribute measurement functions are constructed to compute the attribute measurement of each single index and synthetic attribute measurement.Finally,the identification and classification of risk assessment of safe thickness between a concealed karst cave and a tunnel are recognized by the confidence criterion.The results of two engineering application show that the evaluation results agree well with the site situations in construction.The results provide a good guidance for the tunnel construction.展开更多
Reliable prediction of the potential collapse region of rock mass is a key challenge for deep underground cavity excavation, especially if a concealed karst cave is located above the excavated cavity. Because of the e...Reliable prediction of the potential collapse region of rock mass is a key challenge for deep underground cavity excavation, especially if a concealed karst cave is located above the excavated cavity. Because of the effect of the blast vibration, a possible collapse would occur at a certain region between the concealed karst cave and the excavated cavity. This paper aims to study the roof collapse of a deep buried cavity induced by a concealed karst cave base on a two-dimensional failure mechanism by using upper bound theorem. The failure mechanism is constituted by arbitrary curves which is similar to the collapse observed in an actual cavity excavation. The shape and range of the collapse block is determined by virtual work equation in conjunction with variational approach. The results obtained by the presented approach are approximate with the numerical results provided by finite difference code, which indicates that the proposed method in this work is valid.展开更多
Frame erasure concealment is studied to solve the problem of rapid speech quality reduction due to the loss of speech parameters during speech transmission. A large hidden Markov model is applied to model the immittan...Frame erasure concealment is studied to solve the problem of rapid speech quality reduction due to the loss of speech parameters during speech transmission. A large hidden Markov model is applied to model the immittance spectral frequency （ISF） parameters in AMR-WB codec to optimally estimate the lost ISFs based on the minimum mean square error （MMSE） rule. The estimated ISFs are weighted with the ones of their previous neighbors to smooth the speech, resulting in the actual concealed ISF vectors. They are used instead of the lost ISFs in the speech synthesis on the receiver. Comparison is made between the speech concealed by this algorithm and by Annex I of G. 722. 2 specification, and simulation shows that the proposed concealment algorithm can lead to better performance in terms of frequency-weighted spectral distortion and signal-to-noise ratio compared to the baseline method, with an increase of 2.41 dB in signal-to-noise ratio （SNR） and a reduction of 0. 885 dB in frequency-weighted spectral distortion.展开更多
In this study, four 1/5 scaled shaking table tests were conducted to investigate the seismic performance of recycled concrete frame-shear wall structures with different recycled aggregates replacement rates and concea...In this study, four 1/5 scaled shaking table tests were conducted to investigate the seismic performance of recycled concrete frame-shear wall structures with different recycled aggregates replacement rates and concealed bracing detail. The four tested structures included one normal concrete model, one recycled coarse aggregate concrete model, and two recycled coarse and fi ne aggregate concrete models with or without concealed bracings inside the shear walls. The dynamic characteristics, dynamic response and failure mode of each model were compared and analyzed. Finite element models were also developed and nonlinear time-history response analysis was conducted. The test and analysis results show that the seismic performance of the recycled coarse aggregate concrete frame-shear wall structure is slightly worse than the normal concrete structure. The seismic resistance capacity of the recycled concrete frame-shear wall structure can be greatly improved by setting up concealed bracings inside the walls. With appropriate design, the recycled coarse aggregate concrete frame-shear wall structure and recycled concrete structure with concealed bracings inside the walls can be applied in buildings.展开更多
文摘Isolated male epispadias typically presents with preputial defects and dorsal urethral dehiscence. A less common subtype, known as concealed epispadias, is distinguished by an intact prepuce. Despite its clinical relevance, there is limited literature on this variant. In this study, we retrospectively analyzed the clinical data of 86 pediatric patients with isolated male epispadias treated in Beijing Children’s Hospital (Beijing, China) from May 2004 to July 2023, including 19 cases of concealed epispadias and 67 of nonconcealed epispadias. We compared clinical characteristics, preoperative diagnostics, surgical techniques, postoperative outcomes, and sexual function during follow-up between the concealed and nonconcealed groups. No significant differences were observed between the two groups regarding surgical methods, postoperative complications, or rates of urinary incontinence. However, notable distinctions were found in the age at initial diagnosis, timing of surgery, frequency of incontinence, location of the urethral meatus, and postoperative urinary incontinence scores (all P < 0.05). Given the absence of penopubic epispadias in concealed cases, we categorized glans and penile epispadias within nonconcealed epispadias as distal epispadias (n = 40) and subsequently compared them with concealed epispadias cases. The postoperative urinary incontinence scores did not differ significantly between the concealed and distal epispadias groups. These findings suggest that concealed epispadias represents a relatively milder form of the condition, characterized by the absence of penopubic involvement, lower rates of urinary incontinence, and favorable surgical outcomes. However, the intact prepuce in concealed cases underscores the need for careful identification and early diagnosis.
基金sponsored by the National Natural Science Foundation of China No.U24B201114,6247070859,62302114 and No.62172353Innovation Fund Program of the Engineering Research Center for Integration and Application of Digital Learning Technology of Ministry of Education No.1331007 and No.1311022Natural Science Foundation of Guangdong Province No.2024A1515010177.
文摘Blockchain,as a distributed ledger,inherently possesses tamper-resistant capabilities,creating a natural channel for covert communication.However,the immutable nature of data storage might introduce challenges to communication security.This study introduces a blockchain-based covert communication model utilizing dynamic Base-K encoding.The proposed encoding scheme utilizes the input address sequence to determine K to encode the secret message and determines the order of transactions based on K,thus ensuring effective concealment of the message.The dynamic encoding parameters enhance flexibility and address issues related to identical transaction amounts for the same secret message.Experimental results demonstrate that the proposed method maintains smooth communication and low susceptibility to tampering,achieving commendable concealment and embedding rates.
基金the Key Laboratory of Geochemical Exploration, Institute of Geophysical and Geochemical Exploration, China Geological Survey, and Ministry of Natural Resources of the People’s Republic of China for funding this researchsupported by National Nonprofit Institute Research Grant of Institute of Geophysical and Geochemical Exploration (AS2022P03)Key Laboratory of Ionic Rare Earth Resources and Environment, Ministry of Natural Resources of the People’s Republic of China (No. 2022IRERE101 and No. 2023IRERE102)
文摘Mineral exploration under exotic overburden has been a great challenge in exploration geochemistry.Gas geochemical measurement is a potential method for mineral exploration due to the characteristics of strong penetrability and vertical migration.The previous rapid gas analyzer cannot determine low concentrations of soil gases because of inadequate sensitivity,therefore,it is necessary to develop a more sensitive analytical technique.In this paper,the pilot studies on CO_(2) and SO_(2) geochemical measurements were performed at the Zhuxi W-(Cu)deposit,Jiapigou gold ore-concentrated area,and Tukuzbay gold deposit.This study employed rapid gas analyzer based on Infrared Absorption Spectroscopy and Electrochemical Analysis,which can detect low concentrations of CO_(2) and SO_(2) and greatly improve the reliability of test data.The results show that CO_(2) and SO_(2) show clear anomalies over deeply concealed ore bodies and faults,demonstrating that CO_(2) and SO_(2) anomalies can reveal indicative information about concealed mineralization and faults.Moreover,CO_(2) and SO_(2) anomalies can identify mineralization information exceeding 1,000 m in depth,suggesting that this method has large detection depth.Therefore,CO_(2) and SO_(2) geochemical measurement method is a feasible tool to discern deeply concealed mineralization and faults,and can provide a new idea in prospecting for concealed ore deposits in covered areas.
基金Ministry of Science and Technology of China under Grant No.2023YFC3804300National Science Foundation of China under Grant No.52178114。
文摘Actuator dynamics introduce a synchronization disparity between commanded displacements transmitted to the actuator and the actual displacements generated by the actuator,thereby affecting its precision and potentially leading to instability in real-time hybrid simulation(RTHS).This study aims to elucidate the relationship between calculated and measured displacements by analyzing their magnitude and phase in the frequency domain via transformations.The physical implications of these relationships are explored in the context of frequency domain evaluation indices(FEI),the transfer function of actuator dynamics,and delay compensation.Formulations for achieving perfect compensation of actuator dynamics are developed,and an enhanced compensation approach,termed improved windowed frequency domain evaluation index-based compensation(IWFEI),is introduced.The efficacy of IWFEI is assessed using a RTHS benchmark model,with perturbed simulations conducted to validate its robustness.Uncertainties inherent in actuator dynamics are represented as random variables in these simulations.Comparative analysis of the mean values and variances of evaluation criteria demonstrates that IWFEI enables more accurate and robust compensation.Furthermore,strong correlations observed among criteria in the time and frequency domains underscore the effectiveness of the proposed frequency domain-based compensation method in mitigating amplitude errors and phase delays in RTHS.
文摘Structures modelled with flexible-base assumptions,incorporating soil effects,generally exhibit longer natural periods and higher damping compared to fixed-base models that exclude soil-structure interaction(SSI).However,the beneficial or detrimental nature of SSI remains contentious in current earthquake damage analyses and research findings.This study introduces a numerical modelling technique,validated by experimental shaking table tests,to examine the effects of SSI on high-rise buildings.The study considers various substructure parameters,including foundation types,soil types,and bedrock depths.Both advantageous and adverse impacts of SSI are identified and analysed.Numerical simulations reveal that increased subsoil stiffness significantly amplifies the base shear of structures compared to bedrock depth effects.Additionally,increased foundation rocking results in higher inter-storey drifts and reduced base shear.Overall,SSI tends to amplify inter-storey drifts,indicating detrimental effects.Specifically,the study found that the inclusion of SSI increased maximum inter-storey drifts by up to 38%,particularly in softer soils,while reducing base shear by up to 44%in structures with classical compensated foundations on D_(e)and E_(e)soil types.In contrast,piled foundation systems experienced an increase in base shear of up to 27%under the same conditions.Conversely,SSI has beneficial impacts on base shear for structures with classical compensated foundations on soil types of D_(e)and E_(e),as it reduces the base shear.For structures with piled foundations and those with classical compensated foundations on C_(e)soil,SSI effects are detrimental.C_(e),D_(e),and E_(e)soils correspond to geotechnical classifications per AS1170,representing stiff,medium,and soft soils respectively.The study also presents minimum base shear ratios considering SSI reduction effects for various foundation types.
基金jointly funded by the guangxi Science and Technology Base and Talent Project(AD23026104)the Key Research and Development Program Project in Guangxi(AB23026121)。
文摘Due to the influence of karst cave development and route selection,the location relationship between concealed karst cave and tunnel is more random.In order to explore the influence rule of karst cave location on the minimum safe thickness of water-proof rock mass,a simplified calculation model of water-proof rock mass thickness when the karst cave is located at any location around the tunnel is established,and the influence of multiple factors on the overall stability of water-proof rock mass is considered.Based on the cusp catastrophe theory,the analytical expressions for the safety thickness of waterproof rock mass are derived.Based on the finite difference principle,the analytical expressions of the safety thickness of water-proof rock mass are verified.In order to improve the application range of the analytical formula derived in this paper,the analytical formula is optimized based on the instability principle differences between the simplified calculation model and the elastic compressive bar.The research results show that the necessary condition solution is more applicable and much safer than the sufficient condition solution.Tectonic stress,rock beam length and karst cave water pressure are significantly positively correlated with the safe thickness of the waterproof rock mass.The calculated results of the semioptimized formula and the unoptimized formula are constant values,independent of the karst cave location.While the calculated results of the fully optimized formula are variable values,correlated with the karst cave location,the thickness of the waterproof rock mass gradually decreases as the karst cave location moves from the top of the tunnel to the bottom of the tunnel.The unoptimized formula does not consider the influence of the lateral force of the rock beam,and is not suitable for the working condition with large lateral force,the calculation results of the semi-optimized formula and the fully optimized formula are not very different and are biased to safety,so it can be given priority.
文摘In the construction of shallow-buried concealed tunnels,the control of surrounding rock stability is a core challenge,which is crucial to construction safety and structural performance.A two-dimensional model was established using Midas GTS NX,combined with bench cut method excavation simulation.The laws of vault and surface settlement were quantitatively analyzed through displacement nephograms,and the spatiotemporal characteristics of surrounding rock displacement were revealed.The results show that under the established excavation and support measures,the displacement and settlement meet the specification requirements.Meanwhile,the Analytic Hierarchy Process(AHP)was introduced to determine weights and analyze the coupling correlation of factors through judgment matrices,clarifying the influence degrees of surrounding rock grade,support strength,and other factors to achieve multi-dimensional evaluation.Furthermore,the Fuzzy Comprehensive Evaluation method was integrated to quantify the mapping relationship between surrounding rock stability and safety,and the safety grade was obtained.Finally,measures such as strengthening support,optimizing excavation parameters,refined exploration,and improving management were proposed to enhance surrounding rock stability and reduce construction risks.
基金supported by the National Natural Science Foundation of China(No.81860268,and No.82201000)Ningxia Natural Science Foundation(No.2021AAC02025)+2 种基金Ningxia science and technology innovation leading talent training project(No.2020GKLRLX06 and No.2020GKLRLX11)Ningxia Medical University research project(No.XTJKF240315)Ningxia Key Research and Development Project(No.2023BEG03021 and No.2021BEB04034).
文摘To evaluate the therapeutic effect of a modified Devine procedure with a subcutaneous sliding fixation method for the treatment of congenital concealed penis,we retrospectively selected 45 patients with congenital concealed penises who were admitted to General Hospital of Ningxia Medical University(Yinchuan,China)between September 2020 and November 2023.In all cases,the penis was observed to be short,and retracting the skin at the base revealed a normal penile body,which immediately returned to its original position upon release.All patients underwent the modified Devine procedure with subcutaneous sliding fixation and completed a 12-week postoperative follow-up.A statistically significant increase in penile length was observed postoperatively,with the median length increasing from 4.0(interquartile range[IQR]:3.5–4.8;95%confidence interval[CI]:3.9–4.4)cm to 8.0(IQR:7.8–8.0;95%CI:7.7–7.9)cm,with P<0.001.The parents were satisfied with the outcomes,including increased penile length,improved hygiene,and enhanced esthetics.Except for mild foreskin edema in all cases,no complications(such as infections,skin necrosis,or penile retraction)were observed.The edema was resolved within 4 weeks after the operation.This study demonstrates that the modified Devine procedure utilizing the subcutaneous sliding fixation method yields excellent outcomes with minimal postoperative complications,reduced penile retraction,and high satisfaction rates among patients and their families.
基金supported by the National Key R&D Program of China(Grant No.2022YFC3080200)。
文摘The identification and characterization of concealed in-situ rock blocks on high-steep slope exposures are critical in rock engineering,but remain challenging.This study employs advanced UAV-based photogrammetry to capture high-resolution discontinuity data and develops a fully automated rock block extraction method consisting of three steps:(1)determination of free face and non-free fracture intersections,(2)surface search for rock blocks on free face.and(3)extraction and analysis of rock blocks.This approach simplifies the determination of discontinuity intersections while maintaining high accuracy.By incorporating all types of discontinuities contributing to rock block formation,the method enables precise in-situ rock block identification and extraction.Application to a rock slope in China,produced results consistent with the rock blocks observed in the 3D model,highlighting its accuracy and practical value.
基金This work is supported by the National Key R&D Program of China under grant 2018YFB1003205by the National Natural Science Foundation of China under grant U1536206,U1405254,61772283,61602253,61672294,61502242+2 种基金by the Jiangsu Basic Research Programs-Natural Science Foundation under grant numbers BK20150925 and BK20151530by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)fundby the Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET)fund,China.
文摘Deep neural network has proven to be very effective in computer vision fields.Deep convolutional network can learn the most suitable features of certain images without specific measure functions and outperform lots of traditional image processing methods.Generative adversarial network(GAN)is becoming one of the highlights among these deep neural networks.GAN is capable of generating realistic images which are imperceptible to the human vision system so that the generated images can be directly used as intermediate medium for many tasks.One promising application of using GAN generated images would be image concealing which requires the embedded image looks like not being tampered to human vision system and also undetectable to most analyzers.Texture synthesizing has drawn lots of attention in computer vision field and is used for image concealing in steganography and watermark.The traditional methods which use synthesized textures for information hiding mainly select features and mathematic functions by human metrics and usually have a low embedding rate.This paper takes advantage of the generative network and proposes an approach for synthesizing complex texture-like image of arbitrary size using a modified deep convolutional generative adversarial network(DCGAN),and then demonstrates the feasibility of embedding another image inside the generated texture while the difference between the two images is nearly invisible to the human eyes.
文摘In this paper, a new method of time reversal for defect diagnosis of concealed structure has been proposed based on the detecting technique of structure acoustic wave and the theory of time reversal. The time reversal recurrence formula for detecting the acoustic wave speed constitution of concealed structures with bilevel asynchronous test has been established. The wave speed constitution can be reconstructed in 2 D graticule form by means of this method. The result of model test shows the method is valid.
文摘Since real world communication channels are not error free, the coded data transmitted on them may be corrupted, and block based image coding systems are vulnerable to transmission impairment. So the best neighborhood match method using genetic algorithm is used to conceal the error blocks. Experimental results show that the searching space can be greatly reduced by using genetic algorithm compared with exhaustive searching method, and good image quality is achieved. The peak signal noise ratios(PSNRs) of the restored images are increased greatly.
基金Supported by the Science and Technology Program of the Education Department of Shaanxi Provincial Government(09JK378)the Key Scientific Research Fund of Shaanxi University of Technology(SLGKY12-02)~~
文摘With the rural concealed communication cable as the study object, the shielding effectiveness of different slot shapes was analyzed by using LBEM （linear boundary element method）. The engineering example results showed that for twocore shielded cable, the coupling capacitance of trapezoid slots （asymmetric and symmetric） changed the most, followed by rectangular slots （asymmetric and symmetric）, and the changes of wedge slots were the smallest, but the change tenden- cies were consistent. In addition, with the increase of slot width of different slots, the coupling capacitance of tow-cored shielded cable showed small change.
基金supported by the National Natural Science Foundation of China(81572870)
文摘Objective:To explore the relationship between cancer awareness and the survival of the patients with non-small cell lung carcinoma(NSCLC).Methods:A total of 865 NSCLC patients were screened for the risk factors,including age,gender,address,tumor/lymph nodes/metastasis(TNM)stage,and cancer awareness.Survival of the patients was calculated by Kaplan-Meier method and Cox regression analysis.Results:After an average observation time of 304 d(ranging from 0 to 4718 d),62 of the 394 patients in the cancer awareness group survived,whereas 26 of the 471 patients in the cancer concealment group survived.Cancer-specific and all-cause survival was poorer in the cancer concealment group(P<0.001 for each,log-rank test).Cox multivariate regression analysis showed that cancer concealment displayed significantly lower cancer-specific survival[hazard ratio(HR)=1.534,95%con fi dence interval(CI)1.320 to 1.784,P<0.001]and all-cause survival(HR=1.558,95%CI 1.346 to 1.803,P<0.001).Conclusion:Cancer concealment is associated with a poor survival of NSCLC patients,which may prohibit the patients from obtaining the real“right to survival”.
基金The work is sponsored by National Natural Science Foundation of China (No. 40074036).
文摘A successful case history of exploring for concealed structure using the high-resolution EM method in the investigation of the West-East Gas Pipeline Project＇s B Tunnel is presented in this paper. The high frequency electromagnetic image system named STRATAGEM EH4, operating at frequencies ranging from 90KHz to 1Hz, was used for data acquisition. The orthogonal components of the electromagnetic field were measured during the field acquisition and the relevant electromagnetic attributes of the object body were extracted from the electromagnetic data. Hybrid sources, consisting of natural and full tensor-controlled sources, were utilized to produce high-quality electromagnetic field data. B Tunnel lies in the western part of Hubei province, at depths of less than 200m. The geologic setting of B tunnel is very complex. Following an initial geologic investigation, an outcrop considered to be a bedrock interface by investigators, collapsed during tunneling operations. A second investigation applied high-resolution EM and seismic refraction methods to reveal a more complex geologic structure along the tunnel route. The predicted rock classes and fault were encountered during the subsequent tunneling operations.
基金Projects(51509147,51879153) supported by the National Natural Science Foundation of ChinaProjects(2017JC002,2017JC001) supported by the Fundamental Research Funds of Shandong University,China
文摘An attribute recognition model for safe thickness assessment between a concealed karst cave and a tunnel is established based on the attribute mathematic theory.The model can be applied to carrying out risk classification of the safe thickness between a concealed karst cave and a tunnel and to guarantee construction’s safety in tunnel engineering.Firstly,the assessment indicators and classification standard of safe thickness between a concealed karst cave and a tunnel are studied based on the perturbation method.Then some attribute measurement functions are constructed to compute the attribute measurement of each single index and synthetic attribute measurement.Finally,the identification and classification of risk assessment of safe thickness between a concealed karst cave and a tunnel are recognized by the confidence criterion.The results of two engineering application show that the evaluation results agree well with the site situations in construction.The results provide a good guidance for the tunnel construction.
基金Projects(51878074,51678071)supported by the National Natural Science Foundation of China
文摘Reliable prediction of the potential collapse region of rock mass is a key challenge for deep underground cavity excavation, especially if a concealed karst cave is located above the excavated cavity. Because of the effect of the blast vibration, a possible collapse would occur at a certain region between the concealed karst cave and the excavated cavity. This paper aims to study the roof collapse of a deep buried cavity induced by a concealed karst cave base on a two-dimensional failure mechanism by using upper bound theorem. The failure mechanism is constituted by arbitrary curves which is similar to the collapse observed in an actual cavity excavation. The shape and range of the collapse block is determined by virtual work equation in conjunction with variational approach. The results obtained by the presented approach are approximate with the numerical results provided by finite difference code, which indicates that the proposed method in this work is valid.
基金The Science Foundation of Southeast University(No.XJ0704268)the Natural Science Foundation of the Education Department of Anhui Province(No.KJ2007B088)
文摘Frame erasure concealment is studied to solve the problem of rapid speech quality reduction due to the loss of speech parameters during speech transmission. A large hidden Markov model is applied to model the immittance spectral frequency （ISF） parameters in AMR-WB codec to optimally estimate the lost ISFs based on the minimum mean square error （MMSE） rule. The estimated ISFs are weighted with the ones of their previous neighbors to smooth the speech, resulting in the actual concealed ISF vectors. They are used instead of the lost ISFs in the speech synthesis on the receiver. Comparison is made between the speech concealed by this algorithm and by Annex I of G. 722. 2 specification, and simulation shows that the proposed concealment algorithm can lead to better performance in terms of frequency-weighted spectral distortion and signal-to-noise ratio compared to the baseline method, with an increase of 2.41 dB in signal-to-noise ratio （SNR） and a reduction of 0. 885 dB in frequency-weighted spectral distortion.
基金National Science and Technology Support Program of China under Grant No.2011BAJ08B02Natural Science Foundation of Beijing under Grant No.8132016Beijing City University Youth Backbone Talent Training Project under Grant No.PHR201108009
文摘In this study, four 1/5 scaled shaking table tests were conducted to investigate the seismic performance of recycled concrete frame-shear wall structures with different recycled aggregates replacement rates and concealed bracing detail. The four tested structures included one normal concrete model, one recycled coarse aggregate concrete model, and two recycled coarse and fi ne aggregate concrete models with or without concealed bracings inside the shear walls. The dynamic characteristics, dynamic response and failure mode of each model were compared and analyzed. Finite element models were also developed and nonlinear time-history response analysis was conducted. The test and analysis results show that the seismic performance of the recycled coarse aggregate concrete frame-shear wall structure is slightly worse than the normal concrete structure. The seismic resistance capacity of the recycled concrete frame-shear wall structure can be greatly improved by setting up concealed bracings inside the walls. With appropriate design, the recycled coarse aggregate concrete frame-shear wall structure and recycled concrete structure with concealed bracings inside the walls can be applied in buildings.
