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Med-ReLU: A Parameter-Free Hybrid Activation Function for Deep Artificial Neural Network Used in Medical Image Segmentation
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作者 Nawaf Waqas muhammad islam +3 位作者 muhammad Yahya Shabana Habib Mohammed Aloraini Sheroz Khan 《Computers, Materials & Continua》 2025年第8期3029-3051,共23页
Deep learning(DL),derived from the domain of Artificial Neural Networks(ANN),forms one of the most essential components of modern deep learning algorithms.DL segmentation models rely on layer-by-layer convolution-base... Deep learning(DL),derived from the domain of Artificial Neural Networks(ANN),forms one of the most essential components of modern deep learning algorithms.DL segmentation models rely on layer-by-layer convolution-based feature representation,guided by forward and backward propagation.Acritical aspect of this process is the selection of an appropriate activation function(AF)to ensure robustmodel learning.However,existing activation functions often fail to effectively address the vanishing gradient problem or are complicated by the need for manual parameter tuning.Most current research on activation function design focuses on classification tasks using natural image datasets such asMNIST,CIFAR-10,and CIFAR-100.To address this gap,this study proposesMed-ReLU,a novel activation function specifically designed for medical image segmentation.Med-ReLU prevents deep learning models fromsuffering dead neurons or vanishing gradient issues.It is a hybrid activation function that combines the properties of ReLU and Softsign.For positive inputs,Med-ReLU adopts the linear behavior of ReLU to avoid vanishing gradients,while for negative inputs,it exhibits the Softsign’s polynomial convergence,ensuring robust training and avoiding inactive neurons across the training set.The training performance and segmentation accuracy ofMed-ReLU have been thoroughly evaluated,demonstrating stable learning behavior and resistance to overfitting.It consistently outperforms state-of-the-art activation functions inmedical image segmentation tasks.Designed as a parameter-free function,Med-ReLU is simple to implement in complex deep learning architectures,and its effectiveness spans various neural network models and anomaly detection scenarios. 展开更多
关键词 Medical image segmentation U-Net deep learning models activation function
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Gastric juice for the diagnosis of H pylori infection in patients on proton pump inhibitors 被引量:4
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作者 Javed Yakoob Shahid Rasool +4 位作者 Zaigham Abbas Wasim Jafri Shahab Abid muhammad islam Zubair Ahmad 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第10期1539-1543,共5页
AIM: To determine the efficacy of gastric juice polymerase chain reaction (PCR) for the detection of H pylori infection in comparison with histology and gastric antral biopsy PCR in patients on a proton pump inhibitor... AIM: To determine the efficacy of gastric juice polymerase chain reaction (PCR) for the detection of H pylori infection in comparison with histology and gastric antral biopsy PCR in patients on a proton pump inhibitor (PPI). METHODS: Eighty-five consecutive patients with dyspeptic symptoms were enrolled. Gastric biopsies for histology, PCR and gastric juice were collected at endoscopy for PCR of the H pylori urease C gene (ure C). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, positive and negative likelihood ratio for PCR of gastric juice for the H pylori ure C gene was compared to histology and gastric antral biopsy H pylori ure C PCR in patients with and without PPI. RESULTS: Gastric juice PCR was positive in 66 (78%) patients. Histology showed H pylori associated gastritis in 57 (67%). Gastric biopsy PCR was positive in 72 (85%). In patients not taking PPI, the sensitivity, specificity, PPV, NPV, accuracy and positive and negative likelihood ratio for gastric juice PCR were 89%, 72%, 91%, 67%, 90%, 85%, 3.1 and 0.1 respectively. In patients on PPI these values were 86%, 100%%, 100%, 29%, 86%, 9.5 and 1.4, respectively. CONCLUSION: Gastric juice PCR for the diagnosis of H pylori infection has increased sensitivity compared to histology with PPI. The use of gastric juice PCR is recommended to confirm H pylori status in patients taking PPIs. 展开更多
关键词 H pylori Proton pump inhibitor Gastric juice Polymerase chain reaction HISTOLOGY
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Candida esophagitis:Risk factors in non-HIV population in Pakistan 被引量:2
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作者 Javed Yakoob Wasim Jafri +5 位作者 Shahab Abid Nadeem Jafri muhammad islam Saeed Hamid Hasnain A Shah Akbar S Hussainy 《World Journal of Gastroenterology》 SCIE CAS CSCD 2003年第10期2328-2331,共4页
AIM:Candida esophagitis is a frequent infection in immunocompromised patients. This study was designed to determine its characteristics in non- human immune deficiency virus (HIV) infected patients attending a teachin... AIM:Candida esophagitis is a frequent infection in immunocompromised patients. This study was designed to determine its characteristics in non- human immune deficiency virus (HIV) infected patients attending a teaching hospital.METHODS: Clinical records of all patients coded by international classification of diseases 9th revision with clinical modifications'(ICD-9-CM), with candida esophagitis diagnosed by esophagogastroduodenoscopy (EGD) and histopathology over a period of 5 years were studied.RESULTS: Fifty-one patients (27 males, 24 females, range 21-77 years old and mean age 52.9 years) fulfilled the criteria (0.34% of the EGD). The common predisposing factors were carcinoma (OR 3.87, CI 1.00-14.99) and diabetes mellitus (OR 4.39, CI 1.34-14.42). The frequent clinical symptoms were retrosternal discomfort, dysphagia and epigastric abdominal pain with endoscopic appearance of scattered mucosal plaques. Another endoscopic lesion was associated with candida esophagitis in 15% patients.CONCLUSION: Carcinomas, diabetes mellitus, corticosteroid and antibiotic therapy are major risk factors for candida esophagitis in Pakistan. It is an easily managed complication that responds to treatment with nystatin. 展开更多
关键词 Adult Aged CANDIDIASIS Endoscopy ESOPHAGITIS Female HIV Infections Hepatitis B Hepatitis C Humans HYPERPLASIA Incidence Lymphocyte Count Male Middle Aged NEUTROPHILS Pakistan Risk Factors
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Prevalence of non-Helicobacter pylori duodenal ulcer in Karachi,Pakistan 被引量:6
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作者 Javed Yakoob Wasim Jafri +5 位作者 Nadim Jafri muhammad islam Shahab Abid Saeed Hamid Hasnain AliShah Hizbullah Shaikh 《World Journal of Gastroenterology》 SCIE CAS CSCD 2005年第23期3562-3565,共4页
AIM:To determine the prevalence of non-Helicobacter pylori (H pylori)-related duodenal ulcer in patients with acid-peptic diseases. METHODS: Medical records of patients who attended the Gastroenterology Department at ... AIM:To determine the prevalence of non-Helicobacter pylori (H pylori)-related duodenal ulcer in patients with acid-peptic diseases. METHODS: Medical records of patients who attended the Gastroenterology Department at Aga Khan University Hospital from 1999 to 2001 and had endoscopic diagnosis of duodenal ulcers were reviewed. Duodenal ulcer associated with H pylori was diagnosed on the basis of endoscopy, rapid urease test and histopathology whereas histories of aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) related duodenal ulcers. Non-H pylori, non-NSAID duodenal ulcers were those without H pylori infection and history of NSAID intake. Co-morbid conditions associated were noted. RESULTS: Of 2 260 patients, 10% (217/2 260) had duodenal ulcer. Duodenal ulcer related to H pylori infection accounted for 53% (116/217), NSAID-related 10% (22/217), non-H pylori non-NSAID 29% (62/217), and 8% (17/217) had both H pylori infection and histories of NSAID intake. Fifteen percent (18/116)_patients had past histories of peptic ulcer disease in H pylori infection, while 8% (5/62) in non-H pylori non-NSAID ulcer. Co-morbid conditions in H pylori infection were seen in 23% (27/116) and 34% (21/62) in non-H pylori non-NSAID ulcer. CONCLUSION: Incidence of H pylori infection related with duodenai ulcer is common. In the presence of co-morbids, non-H pylori and non-NSAID duodenal ulcer is likely to be present. 展开更多
关键词 H pylori Acid-peptic diseases
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Impact of grazing on soil, vegetation and ewe production performances in a semi-arid rangeland 被引量:3
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作者 muhammad islam Abdul RAZZAQ +6 位作者 Shamim GUL Sarfraz AHMAD Taj muhammad Sawsan HASSAN Barbara RISCHKOWSKY M.N.M.IBRAHIM Mounir LOUHAICHI 《Journal of Mountain Science》 SCIE CSCD 2018年第4期685-694,共10页
Controlled grazing is considered a good management strategy to maintain or increase the live weight of livestock and to reduce vegetation degradation of rangelands. The present study investigated soil characteristics,... Controlled grazing is considered a good management strategy to maintain or increase the live weight of livestock and to reduce vegetation degradation of rangelands. The present study investigated soil characteristics, aboveground vegetation biomass dynamics and controlled grazinginduced changes in the live weight of local ewes in the semi-arid rangeland of Ahmadun, Ziarat, Balochistanprovince of Pakistan. An area of 115 ha was protected from livestock grazing in April 2014. In June 2015, soil characteristics within 0-30 cm depth i.e. soil organic matter(SOM), mineral nitrogen, p H and texture in controlled and uncontrolled grazing sites were assessed. Aboveground vegetation biomass measured in early(June) and late summer(August) in 2015 and 2016. The nutritional value i.e. crude protein, phosphorus(P), neutral detergent fiber(NDF), acid detergent fiber(ADF), calcium(Ca), magnesium(Mg) and potassium(K) of dominantplant species were assessed at the beginning of experiment in 2015. Vegetation cover of controlled and uncontrolled grazing sites was also measured during the two years of the study period using the Veg Measure software. From June to November in2015 and 2016, controlled and uncontrolled livestock grazing sites were grazed on a daily basis by local ewes with a stocking rate of 2 and 1 head ha^(-1) respectively. Results reveal that the organic matter contents of coarse-textured, slightly alkaline soil of the study site were in the range of 9.4-17.6 g kg^(-1) soil and showed a strong positive correlation with aboveground vegetation biomass. The biomass of plants was 56.5% and 33% greater at controlled than uncontrolled grazing site in 2015 and 2016 respectively and plant cover was also higher at controlled than uncontrolled grazing site in both years The nutrient contents were significantly(P<0.05)lower in grasses than shrubs. In both years, the controlled grazing increased the weight gain of ewes about two folds compared to the uncontrolled grazing.The results indicate that controlled grazing improved the vegetation biomass production and small ruminant productivity. 展开更多
关键词 Grazing exclosure Soil organic matter Vegetation cover VegMeasure
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Association of post-traumatic stress disorder and work performance: A survey from an emergency medical service, Karachi, Pakistan 被引量:3
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作者 Salima Kerai Omrana Pasha +3 位作者 Uzma Khan muhammad islam Nargis Asad Junaid Razzak 《World Journal of Emergency Medicine》 CAS 2017年第3期214-222,共9页
BACKGROUND: The purpose of the study was to explore the association between posttraumatic stress disorder(PTSD) and work performance of emergency medical services personnel in Karachi, Pakistan.METHODS: Emergency medi... BACKGROUND: The purpose of the study was to explore the association between posttraumatic stress disorder(PTSD) and work performance of emergency medical services personnel in Karachi, Pakistan.METHODS: Emergency medical service personnel were screened for potential PTSD using Impact of Event Scale-Revised(IES-R). Work performance was assessed on the basis of fi ve variables: number of late arrivals to work, number of days absent, number of days sick, adherence to protocol, and patient satisfaction over a period of 3 months. In order to model outcomes like the number of late arrivals to work, days absent and days late, negative binomial regression was applied, whereas logistic regression was applied for adherence to protocol and linear for patient satisfaction scores.RESULTS: Mean scores of PTSD were 24.0±12.2. No association was found between PTSD and work performance measures: number of late arrivals to work(RRadj 0.99; 0.98–1.00), days absent(RRadj 0.98; 0.96–0.99), days sick(RRadj 0.99; 0.98–1.00), adherence to protocol(ORadj 1.01; 0.99–1.04) and patient satisfaction(β 0.001%–0.03%) after adjusting for years of formal schooling, living status, coping mechanism, social support, working hours, years of experience and anxiety or depression.CONCLUSION: No statistically significant association was found between PTSD and work performance amongst EMS personnel in Karachi, Pakistan. 展开更多
关键词 Emergency medical service KARACHI Pakistan Post-traumatic stress disorder STRESS Work performance
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Litter decay in rangeland sites with varying history of human disturbance: a study with Hazargangi Chiltan mountain
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作者 Imran KHAN Shamim GUL +6 位作者 Sarfraz AHMAD Gul Bano REHMAN Agha Waqar YUNUS Iram GUL Imran ALI Ali AKBAR muhammad islam 《Journal of Mountain Science》 SCIE CSCD 2020年第4期898-906,共9页
Hazarganji Chiltan National Park in Balochistan, Pakistan was established in 1980 and the protected area was further extended in 1998. Large area of this mountain is still open for unmanaged human disturbances such as... Hazarganji Chiltan National Park in Balochistan, Pakistan was established in 1980 and the protected area was further extended in 1998. Large area of this mountain is still open for unmanaged human disturbances such as collection of wood for fuel purpose and livestock grazing. Removal of vegetation of rangelands has a significant negative impact on soil organic matter(SOM). This research evaluates litter decomposition in three sites of Hazarganji Chiltan mountain with varying history of human disturbances(unprotected site, young protected site and old protected site). Twigs of Pistacia khinjuk with approximately equal weight and length were placed in litter bags of mesh size 2 mm and were buried in 0-5 cm depth in three sites in January. Half of the twigs of each site received rain simulation in April, August, October, November and January while the other half of the twigs were subjected under natural conditions for 15 months. Twigs from each plot of each treatment of each site were collected from soil after every rain simulation in the previous month of experiment and were processed for weight loss assessment. Results showed that weight loss of twigs by decomposition was significantly higher in the soil of unprotected site as compared to other two sites and there was no difference between rain simulation and control treatments except that loss of weight of twigs of unprotected site was higher under control than rain simulation condition. To confirm that SOM was the major controlling factor for the decomposition of litter decay, soils of each site were collected and burned to remove SOM;thereafter, burned soil samples were mixed with homogenous powder of oven-dried native plants, incubated for 6 months and were provided with dissolved organic matter of the soils of each site. Results showed that there was no difference in the decomposition of litter between soils under controlled laboratory condition, which confirmed that SOM was a major controlling factor for the litter decay in soil under field conditions. The pyrosequencing analysis of the DNA of soils collected from three sites revealed the presence of bacterial species Thermovum composti. 展开更多
关键词 Hazarganji Chiltan National PARK LITTER DECAY GRAZING LITTER BAG Rain simulation
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Giardiasis in patients with dyspeptic symptoms
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作者 Javed Yakoob Wasim Jafri +6 位作者 Shahab Abid Nadim Jafri Saeed Hamid Hasnain Ali Shah Lubna Rizvi muhammad islam Hizbullah Shaikh 《World Journal of Gastroenterology》 SCIE CAS CSCD 2005年第42期6667-6670,共4页
AIM: To investigate the prevalence of giardiasis in patients with dyspeptic symptoms. METHODS" Clinical records of consecutive patients who attended Gastroenterology Department at Aga Khan University Hospital from J... AIM: To investigate the prevalence of giardiasis in patients with dyspeptic symptoms. METHODS" Clinical records of consecutive patients who attended Gastroenterology Department at Aga Khan University Hospital from January 2000 to June 2003 and had esophagogastroduodenoscopy (EGD) with duodenal biopsies and international classification of diseases 9th revision with clinical modifications (ICD-9-CM) coded with giardiasis were studied. RESULTS: Two hundred and twenty patients fulfilled the above criteria. There were 44% (96/220) patients who were giardiasis positive, 72% (69/96) of them were males and 28% (27196) of them were females. There were 65% (81/124) males and 35% (43/124) females who were giardiasis negative. The mean age of patients with giardiasis was 28±17 years, while that of giardiasis negative patients was 40±18 years (P〈0.001). In patients with giardiasis, abdominal pain was present in 71% (68/96) of patients (P = 0.02) and diarrhea in 29% (28/96) (P = 0.005); duodenitis in 25% (24/96) on EGD (P = 0.006) and in 68% (65/96) on histopathology (P = 0.002). CONCLUSION: Giardiasis occurs significantly in young people with abdominal pain, while endoscopic duodenitis is seen in only 25% of giardiasis positive cases, which supports routine duodenal biopsy. 展开更多
关键词 Abdominal pain GIARDIASIS Stool examination EGD Duodenal biopsy
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Sparse Crowd Flow Analysis of Tawaaf of Kaaba During the COVID-19 Pandemic
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作者 Durr-e-Nayab Ali Mustafa Qamar +4 位作者 Rehan Ullah Khan Waleed Albattah Khalil Khan Shabana Habib muhammad islam 《Computers, Materials & Continua》 SCIE EI 2022年第6期5581-5601,共21页
The advent of the COVID-19 pandemic has adversely affected the entire world and has put forth high demand for techniques that remotely manage crowd-related tasks.Video surveillance and crowd management using video ana... The advent of the COVID-19 pandemic has adversely affected the entire world and has put forth high demand for techniques that remotely manage crowd-related tasks.Video surveillance and crowd management using video analysis techniques have significantly impacted today’s research,and numerous applications have been developed in this domain.This research proposed an anomaly detection technique applied to Umrah videos in Kaaba during the COVID-19 pandemic through sparse crowd analysis.Managing theKaaba rituals is crucial since the crowd gathers from around the world and requires proper analysis during these days of the pandemic.The Umrah videos are analyzed,and a system is devised that can track and monitor the crowd flow in Kaaba.The crowd in these videos is sparse due to the pandemic,and we have developed a technique to track the maximum crowd flow and detect any object(person)moving in the direction unlikely of the major flow.We have detected abnormal movement by creating the histograms for the vertical and horizontal flows and applying thresholds to identify the non-majority flow.Our algorithm aims to analyze the crowd through video surveillance and timely detect any abnormal activity tomaintain a smooth crowd flowinKaaba during the pandemic. 展开更多
关键词 Computer vision COVID sparse crowd crowd analysis flow analysis sparse crowd management tawaaf video analysis video processing
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An Improved iBAT-COOP Protocol for Cooperative Diversity in FANETs
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作者 Shahzad Hameed Qurratul-Ain Minhas +4 位作者 Sheeraz Ahmed Shabana Habib Mohammad Kamrul Hasan muhammad islam Sheroz Khan 《Computers, Materials & Continua》 SCIE EI 2021年第5期2527-2546,共20页
Flying ad hoc networks(FANETs)present a challenging environment due to the dynamic and highly mobile nature of the network.Dynamic network topology and uncertain node mobility structure of FANETs do not aim to conside... Flying ad hoc networks(FANETs)present a challenging environment due to the dynamic and highly mobile nature of the network.Dynamic network topology and uncertain node mobility structure of FANETs do not aim to consider only one path transmission.Several different techniques are adopted to address the issues arising in FANETs,from game theory to clustering to channel estimation and other statistical schemes.These approaches mostly employ traditional concepts for problem solutions.One of the novel approaches that provide simpler solutions to more complex problems is to use biologically inspired schemes.Several Nature-inspired schemes address cooperation and alliance which can be used to ensure connectivity among network nodes.One such species that resembles the dynamicity of FANETs are Bats.In this paper,the biologically inspired metaheuristic technique of the BAT Algorithm is proposed to present a routing protocol called iBATCOOP(Improved BAT Algorithm using Cooperation technique).We opt for the design implementation of the natural posture of bats to handle the necessary flying requirements.Moreover,we envision the concept of cooperative diversity using multiple relays and present an iBAT-COOP routing protocol for FANETs.This paper employs cooperation for an optimal route selection and reflects on distance,Signal to Noise Ratio(SNR),and link conditions to an efficient level to deal with FANET’s routing.By way of simulations,the performance of iBAT-COOP protocol outperforms BAT-FANET protocol and reduces packet loss ratio,end-to-end delay,and transmission loss by 81%,21%,and 82%respectively.Furthermore,the average link duration is improved by 25%compared to the BAT-FANET protocol. 展开更多
关键词 Routing protocols UAVS FANETs iBATCOOP BATCOOP
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X-ray Image-Based COVID-19 Patient Detection Using Machine Learning-Based Techniques
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作者 Shabana Habib Saleh Alyahya +4 位作者 Aizaz Ahmed muhammad islam Sheroz Khan Ishrat Khan muhammad Kamil 《Computer Systems Science & Engineering》 SCIE EI 2022年第11期671-682,共12页
In early December 2019,the city of Wuhan,China,reported an outbreak of coronavirus disease(COVID-19),caused by a novel severe acute respiratory syndrome coronavirus-2(SARS-CoV-2).On January 30,2020,the World Health Or... In early December 2019,the city of Wuhan,China,reported an outbreak of coronavirus disease(COVID-19),caused by a novel severe acute respiratory syndrome coronavirus-2(SARS-CoV-2).On January 30,2020,the World Health Organization(WHO)declared the outbreak a global pandemic crisis.In the face of the COVID-19 pandemic,the most important step has been the effective diagnosis and monitoring of infected patients.Identifying COVID-19 using Machine Learning(ML)technologies can help the health care unit through assistive diagnostic suggestions,which can reduce the health unit's burden to a certain extent.This paper investigates the possibilities of ML techniques in identifying/detecting COVID-19 patients including both conventional and exploring from chest X-ray images the effect of viral infection.This approach includes preprocessing,feature extraction,and classification.However,the features are extracted using the Histogram of Oriented(HOG)and Local Binary Pattern(LBP)feature descriptors.Furthermore,for the extracted features classification,six ML models of Support Vector Machine(SVM)and K-Nearest Neighbor(KNN)is used.Experimental results show that the diagnostic accuracy of random forest classifier(RFC)on extracted HOG plusLBP features is as high as 94%followed by SVM at 93%.The sensitivity of the K-nearest neighbour model has reached an accuracy of 88%.Overall,the predicted approach has shown higher classification accuracy and effective diagnostic performance.It is a highly useful tool for clinical practitioners and radiologists to help them in diagnosing and tracking the cases of COVID-19. 展开更多
关键词 Image pre-processing DETECTION classification x-ray images FILTER
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Hajj Crowd Management Using CNN-Based Approach
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作者 Waleed Albattah muhammad Haris Kaka Khel +3 位作者 Shabana Habib muhammad islam Sheroz Khan Kushsairy Abdul Kadir 《Computers, Materials & Continua》 SCIE EI 2021年第2期2183-2197,共15页
Hajj as the Muslim holy pilgrimage,attracts millions of humans to Mecca every year.According to statists,the pilgrimage has attracted close to 2.5 million pilgrims in 2019,and at its peak,it has attracted over 3 milli... Hajj as the Muslim holy pilgrimage,attracts millions of humans to Mecca every year.According to statists,the pilgrimage has attracted close to 2.5 million pilgrims in 2019,and at its peak,it has attracted over 3 million pilgrims in 2012.It is considered as the world’s largest human gathering.Safety makes one of the main concerns with regards to managing the large crowds and ensuring that stampedes and other similar overcrowding accidents are avoided.This paper presents a crowd management system using image classification and an alarm system for managing the millions of crowds during Hajj.The image classification system greatly relies on the appropriate dataset used to train the Convolutional neural network(CNN),which is the deep learning technique that has recently attracted the interest of the research community and industry in varying applications of image classification and speech recognition.The core building block of CNN is is a convolutional layer obtained by the getting CNN trained with patches bearing designated features of the trainee mages.The algorithm is implemented,using the Conv2D layers to activate the CNN as a sequential network.Thus,creating a 2D convolution layer having 64 filters and drop out of 0.5 makes the core of a CNN referred to as a set of KERNELS.The aim is to train the CNN model with mapped image data,and to make it available for use in classifying the crowd as heavily-crowded,crowded,semi-crowded,light crowded,and normal.The utility of these results lies in producing appropriate signals for proving helpful in monitoring the pilgrims.Counting pilgrims from the photos will help the authorities to determine the number of people in certain areas.The results demonstrate the utility of agent-based modeling for Hajj pilgrims. 展开更多
关键词 Crowd management CNN approach HAJJ
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Influence of grazing exclosure on vegetation biomass and soil quality 被引量:2
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作者 Shagufta Qasim Shamim Gul +6 位作者 Maria Hussain Shah Fayyaz Hussain Sarfraz Ahmad muhammad islam Gulbano Rehman muhammad Yaqoob Syed Qasim Shah 《International Soil and Water Conservation Research》 SCIE CSCD 2017年第1期62-68,共7页
This study investigated the influence of sixteen years exclosure from unmanaged grazing on aboveground vegetation biomass,soil organic matter(SOM),soil aggregation and nitrogen(N)mineralization in arid shrubland of Ba... This study investigated the influence of sixteen years exclosure from unmanaged grazing on aboveground vegetation biomass,soil organic matter(SOM),soil aggregation and nitrogen(N)mineralization in arid shrubland of Baluchistan,Pakistan.Sampling was carried out from three sites along the chronosequence of secondary succession.One site was located at open-for-grazing area(grazed site)and the other two sites were located in the area that is protected since 1998.One of the protected site is more remote from grazing(protected site 1)where the land is less disturbed and has thick vegetation than the other protected site(protected site 2).Results showed a significant difference for aboveground vegetation biomass across sites and was in the order of protected site 1>protected site 2>grazed site.Soil organic matter was 53% and 46% higher in protected sites than grazed site.Aggregates larger than 2 mm size were not detected in soil from grazed site but represented 4.5% and 3% of the sample soil profile at the protected site 1 and protected site 2,respectively.Rate of N mineralization was lower in soils at the grazed site as compared to soils at the protected sites.Soil moisture contents were significantly lower at grazed site and showed a strong positive correlation with aboveground vegetation biomass.This study demonstrates that unmanaged grazing severely affected aboveground vegetation biomass,soil organic matter,large-sized soil aggregates,nitrogen mineralization and soil moisture contents.Short term exclosure from grazing(~16 years)can enhance aboveground vegetation biomass and soil quality in terms of soil organic matter accumulation,soil aggregation,retention of soil moisture and nitrogen mineralization in this arid rangeland. 展开更多
关键词 RANGELAND GRAZING Soil organic matter AGGREGATION Nitrogen mineralization
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