In order to improve lesion localisation in small-bowel capsule endoscopy,a modified capsule design has been proposed incorporating localisation and-in theorystabilization capabilities.The proposed design consists of a...In order to improve lesion localisation in small-bowel capsule endoscopy,a modified capsule design has been proposed incorporating localisation and-in theorystabilization capabilities.The proposed design consists of a capsule fitted with protruding wheels attached to a spring-mechanism.This would act as a miniature odometer,leading to more accurate lesion localization information in relation to the onset of the investigation(spring expansion e.g.,pyloric opening).Furthermore,this capsule could allow stabilization of the recorded video as any erratic,non-forward movement through the gut is minimised.Three-dimensional(3-D)printing technology was used to build a capsule prototype.Thereafter,miniature wheels were also 3-D printed and mounted on a spring which was attached to conventional capsule endoscopes for the purpose of this proof-of-concept experiment.In vitro and ex vivo experiments with porcine small-bowel are presented herein.Further experiments have been scheduled.展开更多
AIM： To determine the role of scintigraphy in patients with gastrointestinal （GI） bleeding of unknown Iocalisation. METHODS： We performed retrospective analyses on 92 patients receiving scintigraphies from 1993 to...AIM： To determine the role of scintigraphy in patients with gastrointestinal （GI） bleeding of unknown Iocalisation. METHODS： We performed retrospective analyses on 92 patients receiving scintigraphies from 1993 to 2000 in the University of Regensburg hospital, which were done for Iocalisation of GI bleeding as a diagnostic step after an unsuccessful endoscopy. In addition to the scintigraphies, further diagnostic steps such as endoscopy, angiography or operations were performed. In some of the scintigraphies with negative results, a provocation test for bleeding with heparinisation was carried out. RESULTS： 73% of all scintigraphies showed a positive result. In 4.5% of the positive results, the source was located in the stomach, in 37% the source was the small bowel, in 25% the source was the right colon, in 4.5% the source was the left colon, and in 20% no clear Iocalisation was possible. Only 4% of all scintigraphies were false positive. A reliable positive scintigraphy was independent of the age of the examined patient. A provocation test for bleeding with heparin resulted in an additional 46% of positive scintigraphies with a reliable Iocalisation in primary negative scintigraphies. CONCLUSION- Our results show that scintigraphy and scintigraphy with heparin provocation tests are reliable procedures. They enable a reliable Iocalisation in about half of the obscure GI-bleeding cases. Scintigraphy is superior to angiography in locating a bleeding. It is shown that even in the age of video capsule endoscopy and double-balloon enteroscopy, scintigraphy provides a reliable and directed localization of GI bleeding and offers carefully targeted guidance for other procedures.展开更多
A novel radar-based system for longwall coal mine machine localisation is described. The system, based on a radar-ranging sensor and designed to localise mining equipment with respect to the mine tunnel gate road infr...A novel radar-based system for longwall coal mine machine localisation is described. The system, based on a radar-ranging sensor and designed to localise mining equipment with respect to the mine tunnel gate road infrastructure, is developed and trialled in an underground coal mine. The challenges of reliable sensing in the mine environment are considered, and the use of a radar sensor for localisation is justified. The difficulties of achieving reliable positioning using only the radar sensor are examined. Several probabilistic data processing techniques are explored in order to estimate two key localisation parameters from a single radar signal, namely along-track position and across-track position, with respect to the gate road structures. For the case of across-track position, a conventional Kalman filter approach is sufficient to achieve a reliable estimate. However for along-track position estimation, specific infrastructure elements on the gate road rib-wall must be identified by a tracking algorithm. Due to complexities associated with this data processing problem, a novel visual analytics approach was explored in a 3D interactive display to facilitate identification of significant features for use in a classifier algorithm. Based on the classifier output, identified elements are used as location waypoints to provide a robust and accurate mining equipment localisation estimate.展开更多
To understand the deformational behaviours of geosynthetics-reinforced soil retaining walls(GRS RWs),a series of plane-strain shaking table tests was conducted on retaining wall models.The backfill of the models was m...To understand the deformational behaviours of geosynthetics-reinforced soil retaining walls(GRS RWs),a series of plane-strain shaking table tests was conducted on retaining wall models.The backfill of the models was made of poorly graded gravel.Deformations and strains in the gravelly backfill induced by seismic loading are recorded in real time,which are of importance to understand the seismic strength and stability of the GRS RW systems,as strain localisation development in the backfill and foundation is related to the degree of strength degradation of the system.In the present study,we aimed at quantifying the induced deformations of the GRS RW models due to shaking.Digital image correlation(DIC)technique was then employed to analyse and provide full-field deformation and motion images with the models.It is demonstrated that,unlike conventional contact devices that are yet limited to provide quantities of a singular and fixed location,DIC provides deformation and motion of the area of interests to reveal the evolution of localisation.展开更多
We study via numerical experiments the localisation property of an acoustic wave in a viscoelastic soft medium containing randomly-distributed air bubbles. The behaviours of the oscillation phases of bubbles are parti...We study via numerical experiments the localisation property of an acoustic wave in a viscoelastic soft medium containing randomly-distributed air bubbles. The behaviours of the oscillation phases of bubbles are particularly investigated in various cases for distinguishing efficiently the acoustic localisation from the effects of acoustic absorption caused by the viscosity of medium. The numerical results reveal the phenomenon of ＇phase transition＇ characterized by an unusual collective oscillation of bubbles, which is an effective criterion to unambiguously identify the acoustic localisation in the presence of viscosity. Within the localisation region, the phenomenon of phase transition persists, and a remarkable decrease in the fluctuation of the oscillation phases of bubbles is observed. The localisation phenomenon will be impaired by the enhancement of the viscosity factors, and the extent to which the acoustic wave is localised may be determined by appropriately analyzing the values of the oscillation phases or the amount of reduction of the phase fluctuation. The results are particularly significant for the practical experiments in an attempt to observe the acoustic localisation in such a medium, which is in general subjected to the interference of the great ambiguity resulting from the effect of acoustic absorption.展开更多
The Dictyostelium discoideum AMP-activated protein kinase (AMPK) snfA subcellular localization was studied in AX2 and stable HPF strains by use of AMPK antipeptide antibody and goat anti-rabbit Alexa-Flour 488-conjuga...The Dictyostelium discoideum AMP-activated protein kinase (AMPK) snfA subcellular localization was studied in AX2 and stable HPF strains by use of AMPK antipeptide antibody and goat anti-rabbit Alexa-Flour 488-conjugated IgG antibody. The AMPK exhibited cytosolic localization patterns and uniform focalised concentrations in wild type and the strains alike. Constitutive activation and attenuation of the α subunit expression did not affect subcellular distribution of AMPK. However, snfA expression was more intense in strains in which AMPK was constitutively active compared with the AX2 but lesser in attenuation strains. The localisation of the snfA reinforced the putative standing that it had a plethora of cytoplasmic functions. Moreover, the oxidative cellular function would require a ubiquitous system and might coordinately regulate responses to metabolic requirements. Furthermore, the developmental phases of the life cycle would support the cytosolic localization;and since organelles were potentially reorganized or removed entirely during the transition from vegetative living to fruiting body morphology. This study provided insight into the subcellular distribution of AMPK in Dictyostelium discoideum. We demonstrated that AMPK localization was steady in AX2 and derived strains whether constitutively active or anti-sense inhibited depicting extreme genetic states.展开更多
The paper presents a computational model for elastic waves in a structured weld adjacent to the free surface of an elastic solid. The main emphasis is on the interaction of waves with the micro-structure of the weld. ...The paper presents a computational model for elastic waves in a structured weld adjacent to the free surface of an elastic solid. The main emphasis is on the interaction of waves with the micro-structure of the weld. Effects of localisation and channeling of waves are addressed. A model of a grain structure within the weld is also considered.展开更多
A novel algorithm for localising a robot in a known two-dimensional environment is presented in this paper. An occupancy grid representing the environment is first converted to a distance function that encodes the dis...A novel algorithm for localising a robot in a known two-dimensional environment is presented in this paper. An occupancy grid representing the environment is first converted to a distance function that encodes the distance to the nearest obstacle from any given location. A Chamfer distance based sensor model to associate observations from a laser ranger finder to the map of the environment without the need for ray tracing, data association, or feature extraction is presented. It is shown that the robot can be localised by solving a non-linear optimisation problem formulated to minimise the Chamfer distance with respect to the robot location. The proposed algorithm is able to perform well even when robot odometry is unavailable and requires only a single tuning parameter to operate even in highly dynamic environments. As such, it is superior than the state-of-the-art particle filter based solutions for robot localisation in occupancy grids, provided that an approximate initial location of the robot is available. Experimental results based on simulated and public domain datasets as well as data collected by the authors are used to demonstrate the effectiveness of the proposed algorithm.展开更多
Impact ground pressure events occur frequently in coal mining processes,significantly affecting the personal safety of construction workers.Real-time microseismic monitoring of coal rock body rupture information can p...Impact ground pressure events occur frequently in coal mining processes,significantly affecting the personal safety of construction workers.Real-time microseismic monitoring of coal rock body rupture information can provide early warnings,and the seismic source location method is an essential indicator for evaluating a microseismic monitoring system.This paper proposes a nonlinear hybrid optimal particle swarm optimisation(PSO)microseismic positioning method based on this technique.The method first improves the PSO algorithm by using the global search performance of this method to quickly find a feasible solution and provide a better initial solution for the subsequent solution of the nonlinear optimal microseismic positioning method.This approach effectively prevents the problem of the microseismic positioning method falling into a local optimum because of an over-reliance on the initial value.In addition,the nonlinear optimal microseismic positioning method further narrows the localisation error based on the PSO algorithm.A simulation test demonstrates that the new method has a good positioning effect,and engineering application examples also show that the proposed method has high accuracy and strong positioning stability.The new method is better than the separate positioning method,both overall and in three directions,making it more suitable for solving the microseismic positioning problem.展开更多
为解决瞳孔中心定位算法在光照变化、遮挡及个体差异下鲁棒性不足、耗时较长的问题,提出联合ROI(region of interest)检测与Daugman算法优化的轻量化瞳孔定位算法。构建以GE_ShV2为骨干网络的YOLOv8n模型,通过结构优化降低46.91%计算量...为解决瞳孔中心定位算法在光照变化、遮挡及个体差异下鲁棒性不足、耗时较长的问题,提出联合ROI(region of interest)检测与Daugman算法优化的轻量化瞳孔定位算法。构建以GE_ShV2为骨干网络的YOLOv8n模型,通过结构优化降低46.91%计算量,模型体积和参数分别减少43.55%与46.18%,同时保持99%的检测精度;在颈部网络引入C2f_ESCA模块实现通道稀疏注意力加权,在DySample基础上新增候选点重要性加权抽样,根据噪声可靠度与边缘梯度动态分配采样概率,有效增强边缘感知,减少漏采。对Daugman算法引入灰度差平方和与积分图加速算法,将复杂度从O(N)降至O(1),有效提升定位效率与抗干扰性,缩短定位时间。实验结果表明,改进后的算法在处理边缘细节和光照变化时表现更加稳健。展开更多
基金Supported by SynMed UK related to this workDr.Koulaouzidis A has also received lecture honoraria from Dr Falk PharmaUnited kingdom
文摘In order to improve lesion localisation in small-bowel capsule endoscopy,a modified capsule design has been proposed incorporating localisation and-in theorystabilization capabilities.The proposed design consists of a capsule fitted with protruding wheels attached to a spring-mechanism.This would act as a miniature odometer,leading to more accurate lesion localization information in relation to the onset of the investigation(spring expansion e.g.,pyloric opening).Furthermore,this capsule could allow stabilization of the recorded video as any erratic,non-forward movement through the gut is minimised.Three-dimensional(3-D)printing technology was used to build a capsule prototype.Thereafter,miniature wheels were also 3-D printed and mounted on a spring which was attached to conventional capsule endoscopes for the purpose of this proof-of-concept experiment.In vitro and ex vivo experiments with porcine small-bowel are presented herein.Further experiments have been scheduled.
文摘AIM： To determine the role of scintigraphy in patients with gastrointestinal （GI） bleeding of unknown Iocalisation. METHODS： We performed retrospective analyses on 92 patients receiving scintigraphies from 1993 to 2000 in the University of Regensburg hospital, which were done for Iocalisation of GI bleeding as a diagnostic step after an unsuccessful endoscopy. In addition to the scintigraphies, further diagnostic steps such as endoscopy, angiography or operations were performed. In some of the scintigraphies with negative results, a provocation test for bleeding with heparinisation was carried out. RESULTS： 73% of all scintigraphies showed a positive result. In 4.5% of the positive results, the source was located in the stomach, in 37% the source was the small bowel, in 25% the source was the right colon, in 4.5% the source was the left colon, and in 20% no clear Iocalisation was possible. Only 4% of all scintigraphies were false positive. A reliable positive scintigraphy was independent of the age of the examined patient. A provocation test for bleeding with heparin resulted in an additional 46% of positive scintigraphies with a reliable Iocalisation in primary negative scintigraphies. CONCLUSION- Our results show that scintigraphy and scintigraphy with heparin provocation tests are reliable procedures. They enable a reliable Iocalisation in about half of the obscure GI-bleeding cases. Scintigraphy is superior to angiography in locating a bleeding. It is shown that even in the age of video capsule endoscopy and double-balloon enteroscopy, scintigraphy provides a reliable and directed localization of GI bleeding and offers carefully targeted guidance for other procedures.
文摘A novel radar-based system for longwall coal mine machine localisation is described. The system, based on a radar-ranging sensor and designed to localise mining equipment with respect to the mine tunnel gate road infrastructure, is developed and trialled in an underground coal mine. The challenges of reliable sensing in the mine environment are considered, and the use of a radar sensor for localisation is justified. The difficulties of achieving reliable positioning using only the radar sensor are examined. Several probabilistic data processing techniques are explored in order to estimate two key localisation parameters from a single radar signal, namely along-track position and across-track position, with respect to the gate road structures. For the case of across-track position, a conventional Kalman filter approach is sufficient to achieve a reliable estimate. However for along-track position estimation, specific infrastructure elements on the gate road rib-wall must be identified by a tracking algorithm. Due to complexities associated with this data processing problem, a novel visual analytics approach was explored in a 3D interactive display to facilitate identification of significant features for use in a classifier algorithm. Based on the classifier output, identified elements are used as location waypoints to provide a robust and accurate mining equipment localisation estimate.
基金the Japan Society for the Promotion of Science and their financial support through the JSPS Fellowship Programme to conduct research activities at the University of Tokyo.
文摘To understand the deformational behaviours of geosynthetics-reinforced soil retaining walls(GRS RWs),a series of plane-strain shaking table tests was conducted on retaining wall models.The backfill of the models was made of poorly graded gravel.Deformations and strains in the gravelly backfill induced by seismic loading are recorded in real time,which are of importance to understand the seismic strength and stability of the GRS RW systems,as strain localisation development in the backfill and foundation is related to the degree of strength degradation of the system.In the present study,we aimed at quantifying the induced deformations of the GRS RW models due to shaking.Digital image correlation(DIC)technique was then employed to analyse and provide full-field deformation and motion images with the models.It is demonstrated that,unlike conventional contact devices that are yet limited to provide quantities of a singular and fixed location,DIC provides deformation and motion of the area of interests to reveal the evolution of localisation.
基金supported by the National Natural Science Foundation of China (Grant Nos.10804050 and 10874086)the Ministry of Education of China (Grant Nos.20060284035 and 705017)
文摘We study via numerical experiments the localisation property of an acoustic wave in a viscoelastic soft medium containing randomly-distributed air bubbles. The behaviours of the oscillation phases of bubbles are particularly investigated in various cases for distinguishing efficiently the acoustic localisation from the effects of acoustic absorption caused by the viscosity of medium. The numerical results reveal the phenomenon of ＇phase transition＇ characterized by an unusual collective oscillation of bubbles, which is an effective criterion to unambiguously identify the acoustic localisation in the presence of viscosity. Within the localisation region, the phenomenon of phase transition persists, and a remarkable decrease in the fluctuation of the oscillation phases of bubbles is observed. The localisation phenomenon will be impaired by the enhancement of the viscosity factors, and the extent to which the acoustic wave is localised may be determined by appropriately analyzing the values of the oscillation phases or the amount of reduction of the phase fluctuation. The results are particularly significant for the practical experiments in an attempt to observe the acoustic localisation in such a medium, which is in general subjected to the interference of the great ambiguity resulting from the effect of acoustic absorption.
文摘The Dictyostelium discoideum AMP-activated protein kinase (AMPK) snfA subcellular localization was studied in AX2 and stable HPF strains by use of AMPK antipeptide antibody and goat anti-rabbit Alexa-Flour 488-conjugated IgG antibody. The AMPK exhibited cytosolic localization patterns and uniform focalised concentrations in wild type and the strains alike. Constitutive activation and attenuation of the α subunit expression did not affect subcellular distribution of AMPK. However, snfA expression was more intense in strains in which AMPK was constitutively active compared with the AX2 but lesser in attenuation strains. The localisation of the snfA reinforced the putative standing that it had a plethora of cytoplasmic functions. Moreover, the oxidative cellular function would require a ubiquitous system and might coordinately regulate responses to metabolic requirements. Furthermore, the developmental phases of the life cycle would support the cytosolic localization;and since organelles were potentially reorganized or removed entirely during the transition from vegetative living to fruiting body morphology. This study provided insight into the subcellular distribution of AMPK in Dictyostelium discoideum. We demonstrated that AMPK localization was steady in AX2 and derived strains whether constitutively active or anti-sense inhibited depicting extreme genetic states.
基金supported by a scholarship funded by Serco Technical Assurance Services
文摘The paper presents a computational model for elastic waves in a structured weld adjacent to the free surface of an elastic solid. The main emphasis is on the interaction of waves with the micro-structure of the weld. Effects of localisation and channeling of waves are addressed. A model of a grain structure within the weld is also considered.
文摘A novel algorithm for localising a robot in a known two-dimensional environment is presented in this paper. An occupancy grid representing the environment is first converted to a distance function that encodes the distance to the nearest obstacle from any given location. A Chamfer distance based sensor model to associate observations from a laser ranger finder to the map of the environment without the need for ray tracing, data association, or feature extraction is presented. It is shown that the robot can be localised by solving a non-linear optimisation problem formulated to minimise the Chamfer distance with respect to the robot location. The proposed algorithm is able to perform well even when robot odometry is unavailable and requires only a single tuning parameter to operate even in highly dynamic environments. As such, it is superior than the state-of-the-art particle filter based solutions for robot localisation in occupancy grids, provided that an approximate initial location of the robot is available. Experimental results based on simulated and public domain datasets as well as data collected by the authors are used to demonstrate the effectiveness of the proposed algorithm.
基金supported by the Natural Science Foundation of Henan Province,China.(No,222300420596).
文摘Impact ground pressure events occur frequently in coal mining processes,significantly affecting the personal safety of construction workers.Real-time microseismic monitoring of coal rock body rupture information can provide early warnings,and the seismic source location method is an essential indicator for evaluating a microseismic monitoring system.This paper proposes a nonlinear hybrid optimal particle swarm optimisation(PSO)microseismic positioning method based on this technique.The method first improves the PSO algorithm by using the global search performance of this method to quickly find a feasible solution and provide a better initial solution for the subsequent solution of the nonlinear optimal microseismic positioning method.This approach effectively prevents the problem of the microseismic positioning method falling into a local optimum because of an over-reliance on the initial value.In addition,the nonlinear optimal microseismic positioning method further narrows the localisation error based on the PSO algorithm.A simulation test demonstrates that the new method has a good positioning effect,and engineering application examples also show that the proposed method has high accuracy and strong positioning stability.The new method is better than the separate positioning method,both overall and in three directions,making it more suitable for solving the microseismic positioning problem.
文摘为解决瞳孔中心定位算法在光照变化、遮挡及个体差异下鲁棒性不足、耗时较长的问题,提出联合ROI(region of interest)检测与Daugman算法优化的轻量化瞳孔定位算法。构建以GE_ShV2为骨干网络的YOLOv8n模型,通过结构优化降低46.91%计算量,模型体积和参数分别减少43.55%与46.18%,同时保持99%的检测精度;在颈部网络引入C2f_ESCA模块实现通道稀疏注意力加权,在DySample基础上新增候选点重要性加权抽样,根据噪声可靠度与边缘梯度动态分配采样概率,有效增强边缘感知,减少漏采。对Daugman算法引入灰度差平方和与积分图加速算法,将复杂度从O(N)降至O(1),有效提升定位效率与抗干扰性,缩短定位时间。实验结果表明,改进后的算法在处理边缘细节和光照变化时表现更加稳健。
