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A Non-Preemptive Priority Queueing System with a Single Server Serving Two Queues M/G/1 and M/D/1 with Optional Server Vacations Based on Exhaustive Service of the Priority Units
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作者 Kailash C. Madan 《Applied Mathematics》 2011年第6期791-799,共9页
We study a vacation queueing system with a single server simultaneously dealing with an M/G/1 and an M/D/1 queue. Two classes of units, priority and non-priority, arrive at the system in two independent Poisson stream... We study a vacation queueing system with a single server simultaneously dealing with an M/G/1 and an M/D/1 queue. Two classes of units, priority and non-priority, arrive at the system in two independent Poisson streams. Under a non-preemptive priority rule, the server provides a general service to the priority units and a deterministic service to the non-priority units. We further assume that the server may take a vacation of random length just after serving the last priority unit present in the system. We obtain steady state queue size distribution at a random epoch. Corresponding results for some special cases, including the known results of the M/G/1 and the M/D/1 queues, have been derived. 展开更多
关键词 Non PREEMPTIVE priority QUEUEING SYSTEM Modified Server Vacations Combination of General SERVICE and Deterministic SERVICE Steady State Queue Size Distribution
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Characteristics of Infertile Clientele Attending a Public in Vitro Fertilization Clinic: Appraising Priorities in a Low-Income Country
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作者 Gbolahan O. Obajimi Olugbenga O. Saanu +2 位作者 Ayodeji S. Adeyanju Ademola S. Olutoye Mofiyinfoluwa M. Adeyeye 《Open Journal of Epidemiology》 2024年第2期343-352,共10页
Introduction: Infertilityaffects one in six couples, and it is an important public health issue largely due to thepervasive effects on the emotional and psychological wellbeing of affected couples. In many developing ... Introduction: Infertilityaffects one in six couples, and it is an important public health issue largely due to thepervasive effects on the emotional and psychological wellbeing of affected couples. In many developing nations emphasis is placed on childbirth and inability to fulfill this role can be very distressing. There is an unmet need for assisted reproductive technology (ART) in many developing countries and where facilities exist, they are mostly privately owned, expensive and concentrated in urban areas. To bridge this gap, public fertility clinics have been established to provide subsidized care. Evaluating the characteristics and peculiarities of clientele presenting at these public facilities will aid planning and prioritization of care. Methodology: A descriptive retrospective study of 116 infertile patients presenting to the fertility clinic of the University College Hospital, Ibadan, Nigeria from inception on the 14<sup>th</sup> of February 2019 and 31<sup>st</sup> of December 2022.Data was analyzed using the Statical Package for Social Sciences (IBM, SPSS, New York) version 23. Descriptive statistics were used to summarize the results which were presented with the aid of bar charts and frequency tables. Result: The mean age of the patients was 40.70 ± 6.62 years. Post-menopausal patients accounted for about one-fifth of the study population while 80.2% (93 women) were older than 35 years. The mean duration of infertility was 9.39 ± 6.11years and nine patients (7.8%) had a duration greater than 2 decades. Secondary infertility occurred in 67.2% of the women. Twenty-nine women (25%) had undergone myomectomy prior to presentation. Hypertension (11.2%) was the most prevalent comorbidity. Nineteen patients (16.4%) had used contraceptives in the past with the male condom (36.8%)being the most preponderant. Sixty-seven patients had experienced pregnancy losses before 28 weeks of gestation while just 16 patients (13.8%) had undergone ART, and none was successful. Conclusion: Secondary infertility was the prevalent type of infertility and may not be unconnected with the low contraceptive usage and high risk of sexually transmitted infection. Late presentation coupled with a large proportion of post-menopausal clientele suggests delayed health-seeking behavior most probably due to the prohibitive cost of ART. The need to streamline services offered in public fertility clinics is paramount in low-income countries grappling with scarce resources. A pragmatic approach will involve the provision of low-cost ART, while enhancing gamete donation programs through the implementation of gamete sharing policies. This will invariably bridge the unmet need and skewed access to ART in developing countries. 展开更多
关键词 INFERTILITY Assisted Reproductive Technology LOW-INCOME Priorities.
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Applying an Ordinal Priority Approach Based Neutrosophic Fuzzy Axiomatic Design Approach to Develop Sustainable Geothermal Energy Source
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作者 Chia-Nan Wang Thuy-Duong Thi Pham Nhat-Luong Nhieu 《Energy Engineering》 EI 2024年第8期2039-2064,共26页
Geothermal energy is considered a renewable,environmentally friendly,especially carbon-free,sustainable energy source that can solve the problem of climate change.In general,countries with geothermal energy resources ... Geothermal energy is considered a renewable,environmentally friendly,especially carbon-free,sustainable energy source that can solve the problem of climate change.In general,countries with geothermal energy resources are the ones going through the ring of fire.Therefore,not every country is lucky enough to own this resource.As a country with 117 active volcanoes and within the world’s ring of fire,it is a country whose geothermal resources are estimated to be about 40%of the world’s geothermal energy potential.However,the percentage used compared to the geothermal potential is too small.Therefore,this is the main energy source that Indonesia is aiming to exploit and use.However,the deployment and development of this energy source are still facing many obstacles due to many aspects from budget sources due to high capital costs,factory construction location,quality of resources,and conflicts of the local community.In this context,determining the optimal locations for geothermal energy sites(GES)is one of the most important and necessary issues.To strengthen the selection methods,this study applies a two-layer fuzzy multi-criteria decision-making method.Through the layers,the Ordinal Priority Approach(OPA)is proposed to weight the sub-criteria,the main criterion,and the sustainability factors.In layer 2,the Neutrosophic Fuzzy Axiomatic Design(NFAD)is applied to rank and evaluate potential locations for geothermal plant construction.Choosing the right geothermal energy site can bring low-cost efficiency,no greenhouse gas emissions,and quickly become the main energy source providing electricity for Indonesia.The final ranking shows Papua,Kawah Cibuni,and Moluccas as the three most suitable cities to build geothermal energy systems.Kawah Cibuni was identified as the most potential GES in Indonesia,with a score of 0.46.Papua is the second most promising GES with a score of 0.45.Next is the Moluccas,with a score of 0.39.However,the three least potential sites among the 15 studied sites are Lumut Balai,Moluccas and Patuha,with scores of 0.08,0.11 and 0.17,respectively.The conclusion of this study also classifies positions into groups to aid in decision-making. 展开更多
关键词 Ordinal priority approach neutrosophic fuzzy axiomatic design renewable energy multiple criteria decision making geothermal energy
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COMRADES FOREVER--To Lam’s visit demonstrates that China remains Vietnam’s top foreign policy priority
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作者 Yang Danzhi 《China Report ASEAN》 2024年第8期30-31,共2页
On August 20,2024,General Secretary of the Communist Party of Vietnam(CPV)Central Committee and Vietnamese President To Lam concluded his state visit to China.China was the destination for Lam's first overseas vis... On August 20,2024,General Secretary of the Communist Party of Vietnam(CPV)Central Committee and Vietnamese President To Lam concluded his state visit to China.China was the destination for Lam's first overseas visit after taking office as general secretary of the CPV Central Committee,which clearly demonstrates that the heads of both countries attach importance to developing the bilateral relations and that Vietnam regards China as the strategic choice and top priority for its foreign policy. 展开更多
关键词 policy VIETNAM priority
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Shape Analysis of Agricultural Parcels for Land Consolidation Priorities in Tekirdag Province,Turkey
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作者 Bahadir ALTURK 《Chinese Geographical Science》 SCIE CSCD 2024年第1期93-105,共13页
Shape irregularity,a sub-factor of parcel fragmentation is a problem that hinders sustainable agriculture and is solved using land consolidation projects.Determination of the parcel shape degree contributes significan... Shape irregularity,a sub-factor of parcel fragmentation is a problem that hinders sustainable agriculture and is solved using land consolidation projects.Determination of the parcel shape degree contributes significantly to spatial prioritization where there is also a high probability of achieving positive effects of consolidation projects.This study aims to determine the shape degree of the agricultural parcels both at singular and rural county scales in Tekirdag Province,Turkey in 2020 by combining the parcel shape index(PSI) with the minimum bounding geometry index(MBG) to improve parcel scores.Hot-spot zones of the highly irregular and near optimum parcels were also determined using Getis-Ord G_(i)^(*) statistic.The parcel degrees were classified into four categories,namely highly irregular,irregular,regular and near optimum.The obtained unweighted scores of the parameters exhibit deviations from the expected values.After weighting by pairwise comparison,the values approached ideal scores.Among 346 740 parcels,53% were highly irregular and irregular and 47% were regular and near optimum shapes after weighting whereas these were 70% and 30%,respectively before weighting.The average parcel degree of 63 rural counties was regular while the average parcel degree of the remaining 264 rural counties was irregular.The combined use of PSI and MBG index improved the correctness of the parcel shape score.It could be suggested to use as a tool in land consolidation prioritization. 展开更多
关键词 land consolidation priority parcel shape index(PSI) minimum bounding geometry(MBG) sustainable rural development hot-spot analysis Tekirdag Province TURKEY
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RFID Based Non-Preemptive Random Sleep Scheduling in WSN 被引量:2
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作者 Tianle Zhang Lihua Yin +4 位作者 Xiang Cui Abhishek Behl Fuqiang Dong Ziheng Cheng Kuo Ma 《Computers, Materials & Continua》 SCIE EI 2020年第10期835-845,共11页
In Wireless Sensor Network(WSN),because battery and energy supply are constraints,sleep scheduling is always needed to save energy while maintaining connectivity for packet delivery.Traditional schemes have to ensure ... In Wireless Sensor Network(WSN),because battery and energy supply are constraints,sleep scheduling is always needed to save energy while maintaining connectivity for packet delivery.Traditional schemes have to ensure high duty cycling to ensure enough percentage of active nodes and then derogate the energy efficiency.This paper proposes an RFID based non-preemptive random sleep scheduling scheme with stable low duty cycle.It employs delay tolerant network routing protocol to tackle the frequent disconnections.A low-power RFID based non-preemptive wakeup signal is used to confirm the availability of next-hop before sending packet.It eliminates energy consumption of repeated retransmission of the delayed packets.Moreover,the received wakeup signal is postponed to take effect until the sleep period is finished,and the waken node then responds to the sending node to start the packet delivery.The scheme can keep stable duty cycle and then ensure energy saving effect compared with other sleeping scheduling methods. 展开更多
关键词 Sleep scheduling RFID partially connected Delay Tolerant Network(DTN) wakeup non-preemptive
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Algorithm for Cost Non-preemptive Scheduling of Partial k-Trees
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作者 Yiming Li Zhiqian Ye Xiao Zhou 《Open Journal of Applied Sciences》 2012年第4期233-236,共4页
Let G be a graph, in which each vertex (job) v has a positive integer weight (processing time) p(v) and eachedge (u,v) represented that the pair of jobs u and v cannot be processed in the same slot. In this paper we a... Let G be a graph, in which each vertex (job) v has a positive integer weight (processing time) p(v) and eachedge (u,v) represented that the pair of jobs u and v cannot be processed in the same slot. In this paper we assume that every job is non-preemptive. Let C={1,2,...} be a color set. A multicoloring (scheduling) F of G is to assign each job v a set of p(v) consecutive positive integers (processing consecutive time slots) in C so that any pair of adjacent vertices receive disjoint sets. Such a multicoloring is called a non-preemptive scheduling. The cost non-preemptive scheduling problem is to find an optimal multicoloring of G. 展开更多
关键词 COLORING non-preemptive scheduling PARTIAL K-TREE
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Boundedness and liveness enforcement for labeled Petri nets using transition priority
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作者 Ye-Jia Liu Xun-Bo Li 《Journal of Electronic Science and Technology》 EI CSCD 2023年第4期75-90,共16页
This paper deals with the supervisory control problem of discrete event systems modeled by labeled Petri nets. The system is originally unbounded. First, the solvability of the problem is confirmed. A necessary condit... This paper deals with the supervisory control problem of discrete event systems modeled by labeled Petri nets. The system is originally unbounded. First, the solvability of the problem is confirmed. A necessary condition is given and proven for the existence of a feasible priority-based controller based on the notions of liveness and transition invariants. Next, a cyclic behavior graph is constructed, which shows the reachable markings that guarantee the maximum liveness of the system within a given bound vector. Finally, an on-line control strategy is proposed to enforce boundedness and liveness to the given system by appending priority relations to transitions. The dynamic priority relation changes flexibly according to the current state of the system and enforces the system evolving in a bounded and live manner. In addition, numerical examples are studied to verify the validity of the proposed approach that remains the structure of the plant net and is efficient for on-line control. 展开更多
关键词 BOUNDEDNESS Control strategy LIVENESS Petri nets priority Transition invariant
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Prioritizing the efforts:lived experiences of family when taking care of people with cancer
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作者 Titan Ligita Merry Andriani +2 位作者 Hazwani Hazwani Ersy Aprilya Fransiska Shafira Aulya 《Frontiers of Nursing》 2023年第3期315-322,共8页
Objective:Cancer has one of the highest disease mortality rates.Families are very important in the treatment of people with cancer.By using a phenomenological design,this study aimed to explore the experience of famil... Objective:Cancer has one of the highest disease mortality rates.Families are very important in the treatment of people with cancer.By using a phenomenological design,this study aimed to explore the experience of families in caring for a person with cancer and to identify the needs of these families.Methods:First,eight interviews were under taken with family members selected through a purposive sampling method.Then,another three interviews were conducted for data validation.The collected data were analyzed using the framework method of analysis.Results:The core theme,“Prioritizing the efforts:Being aware of the best we could do for our family,”reflected family’s experiences of caring for a person with cancer and was underpinned by five themes:“Decisions to make,”“Keeping up the good support,”“Acknowledging the others’contributions,”“Assisting my family to alleviate the disease,”and“Adapting to the current situation.”Conclusions:The results suggest that building mutual trust and communication between family and healthcare professionals is vital in decision-making for people with cancer.Family may also work with the person in fulfilling their needs,without disregarding the needs of the family.When suppor ting the needs of people with diabetes,the family requires appropriate information,and thus,healthcare professionals wisely select which information can help the family make a decision regarding the treatment.After administering the treatment and providing information for people with cancer and their family,asking for feedback is required for evaluation. 展开更多
关键词 CANCER DECISION-MAKING FAMILY needs PHENOMENOLOGY priority treatment
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Prevalence of Some World Health Organization Priority Organisms from an Abattoir at Kwata, Anambra State, Nigeria
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作者 Ruth Asikiya Afunwa Chudi Igweze Onyebuchi +4 位作者 Gbadamosi Francis Ayodele Eze Cynthia Adanna Egbuna Roselyn Ikegbune Chidozie Nwakaeze Emmanuel Amobi 《Advances in Microbiology》 2023年第8期420-433,共14页
The abattoir is one of the important sectors in the food industry, therefore the need for close monitoring of everything concerning it to minimize microbial contamination. The aim of the study is to identify bacteria ... The abattoir is one of the important sectors in the food industry, therefore the need for close monitoring of everything concerning it to minimize microbial contamination. The aim of the study is to identify bacteria listed as WHO priority organisms associated with meat from Kwata abattoir in Awka, Anambra state. The study was carried out over a three (3) months period from September to December 2022. Thirteen samples were collected from the floor, table, water, meat, knife and soil in the abattoir. The samples were cultured using streak and spread plate methods on MacConkey and Cetrimide agar. The isolates were identified with the following biochemical tests: catalase, oxidase, citrate and indole tests. Ampiclox levofloxacin, gentamicin, ofloxacin impenem ceftraixone, cefixime, cefuroxime and nitrofurantoin were used for sensitivity test following Kirby Bauer disc diffusion method and biofilm formation was determined using the tube method. The 75 isolates obtained were identified as follows;29.3% E. coli, 26.7% Klebsiella spp., 16% Proteus spp., and 28% Pseudomonas spp. The result of antibiotics sensitivity test interpreted using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints showed that (98%) of the isolates were resistant to the antibiotics used. Test for biofilm formation with 52 isolates showed 31 strong, 12 moderate and 9 weak biofilm formers. The result of this study confirms the presence of bacteria contaminants within the WHO priority list in the abattoir, as such there is need for improved handling of animals. Slaughtering, cleaning and distribution of meat should be done using aseptic procedures. . 展开更多
关键词 ABATTOIR WHO priority Organisms Antibiotic Resistance COMMUNITY
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Priority Detector and Classifier Techniques Based on ML for the IoMT
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作者 Rayan A.Alsemmeari Mohamed Yehia Dahab +1 位作者 Badraddin Alturki Abdulaziz A.Alsulami 《Computers, Materials & Continua》 SCIE EI 2023年第8期1853-1870,共18页
Emerging telemedicine trends,such as the Internet of Medical Things(IoMT),facilitate regular and efficient interactions between medical devices and computing devices.The importance of IoMT comes from the need to conti... Emerging telemedicine trends,such as the Internet of Medical Things(IoMT),facilitate regular and efficient interactions between medical devices and computing devices.The importance of IoMT comes from the need to continuously monitor patients’health conditions in real-time during normal daily activities,which is realized with the help of various wearable devices and sensors.One major health problem is workplace stress,which can lead to cardiovascular disease or psychiatric disorders.Therefore,real-time monitoring of employees’stress in the workplace is essential.Stress levels and the source of stress could be detected early in the fog layer so that the negative consequences can be mitigated sooner.However,overwhelming the fog layer with extensive data will increase the load on fog nodes,leading to computational challenges.This study aims to reduce fog computation by proposing machine learning(ML)models with two phases.The first phase of theMLmodel assesses the priority of the situation based on the stress level.In the second phase,a classifier determines the cause of stress,which was either interruptions or time pressure while completing a task.This approach reduced the computation cost for the fog node,as only high-priority records were transferred to the fog.Low-priority records were forwarded to the cloud.Four MLapproaches were compared in terms of accuracy and prediction speed:Knearest neighbors(KNN),a support vector machine(SVM),a bagged tree(BT),and an artificial neural network(ANN).In our experiments,ANN performed best in both phases because it scored an F1 score of 99.97% and had the highest prediction speed compared with KNN,SVM,and BT. 展开更多
关键词 Machine learning priority detector Internet of Medical Things IoMT fog computing cloud computing
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教育优先发展视域下学校体育高质量育人的理论意涵与实践路径 被引量:5
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作者 燕凌 孙璞 +1 位作者 王莉芳 刘海元 《首都体育学院学报》 CSSCI 北大核心 2024年第1期78-87,共10页
教育优先发展是党和国家提出并长期坚持的重大方针,高质量发展是教育优先发展在新阶段的重要表征。学校体育高质量育人作为教育高质量发展的重要构成,体现出育人目标的素养导向、育人过程的生本导向和要素导向以及育人功效的多元导向等... 教育优先发展是党和国家提出并长期坚持的重大方针,高质量发展是教育优先发展在新阶段的重要表征。学校体育高质量育人作为教育高质量发展的重要构成,体现出育人目标的素养导向、育人过程的生本导向和要素导向以及育人功效的多元导向等特征。新时期推进学校体育高质量育人需要坚持把立德树人作为根本任务,着力培养青少年的核心素养;提升学生体育学习的实际获得感,提高体育师资培养质量,推进体育家校合作;科学认识学校体育促进青少年全面发展的育人价值,充分发挥学校体育的育体功能和育心功能。 展开更多
关键词 教育优先发展 学校体育 高质量育人
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以新质生产力赋能中国式现代化的重点与任务 被引量:42
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作者 任保平 《经济问题》 CSSCI 北大核心 2024年第5期1-6,共6页
发展新质生产力是中国式现代化的主要推动力,以新质生产力赋能中国式现代化是适应我国社会主要矛盾变化背景下推动中国式现代化的新要求,是打造中国式现代化质量版的客观要求,是实现中国式现代化目标转型的必然要求。以新质生产力赋能... 发展新质生产力是中国式现代化的主要推动力,以新质生产力赋能中国式现代化是适应我国社会主要矛盾变化背景下推动中国式现代化的新要求,是打造中国式现代化质量版的客观要求,是实现中国式现代化目标转型的必然要求。以新质生产力赋能中国式现代化的战略重点在于构建现代经济体系、培育现代化新动能、提高供给体系质量。以新质生产力赋能中国式现代化新发展的战略任务是形成以新质生产力赋能中国式现代化的内生驱动力,推动供给侧的产业结构升级,以新质生产力形成中国式现代化新优势;推动动力转换,形成中国式现代化新动力;实现数字经济赋能中国式现代化,以数字新质生产力打造中国式现代化的升级版;以新质生产力推动新型工业化,形成新型工业化的新优势。 展开更多
关键词 新质生产力 中国式现代化 战略重点 战略任务
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A-Kano模型下全过程工程咨询业主需求实证研究 被引量:1
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作者 丁继勇 师婷婷 +2 位作者 张茅 朱俊成 李胜喆 《水力发电学报》 CSCD 北大核心 2024年第6期23-32,共10页
我国全过程工程咨询实践正处于多种模式并存、咨询内容差异较大的探索性阶段。以业主需求为导向,合理确定咨询服务内容,提升全过程工程咨询企业服务能力,是推进全过程工程咨询健康发展的关键。通过梳理相关文献,识别出12种全过程工程咨... 我国全过程工程咨询实践正处于多种模式并存、咨询内容差异较大的探索性阶段。以业主需求为导向,合理确定咨询服务内容,提升全过程工程咨询企业服务能力,是推进全过程工程咨询健康发展的关键。通过梳理相关文献,识别出12种全过程工程咨询业主需求,进而借助A-Kano模型开展正、负向满意度与重要度问卷调查,并计算出各类需求的优先级。实证分析结果表明:工程监理和造价咨询属于基本型需求;项目管理、设计及勘察属于期望型需求;招标代理、前期策划和BIM咨询为兴奋型需求;后期运营、建筑节能与绿色建筑咨询、工程检测服务以及工程保险咨询为无差异需求。基于上述结果为工程咨询企业提出转型建议,使其更好地满足业主集成化、个性化的咨询需求。 展开更多
关键词 全过程工程咨询 业主需求 A-Kano模型 优先级
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The value rationality and tool rationality of Health Priority
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作者 Nian-Yi Yuan 《History & Philosophy of Medicine》 2023年第3期21-24,共4页
Health Priority is increasingly becoming a human need and an international consensus.In addition to the basic value judgment and direction-leading function,Health Priority also has a clear,practical meaning and distin... Health Priority is increasingly becoming a human need and an international consensus.In addition to the basic value judgment and direction-leading function,Health Priority also has a clear,practical meaning and distinct tool attributes.The text adheres to the organic unity of regularity and purpose,follows the modern medical model and the philosophy of system theory,combines the characteristic facts,and discusses the value rationality and tool rationality of Health Priority based on the whole process management,and tries to refine the Health Priority governance model with Chinese characteristics,so as to provide a reference for global health governance. 展开更多
关键词 Health priority value rationality tool rationality Chinese characteristics
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网联混合流高速公路车道管理及通行能力分析 被引量:2
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作者 王正武 陈涛 +1 位作者 向健 贺正冰 《公路交通科技》 CAS CSCD 北大核心 2024年第2期191-202,211,共13页
为提高网联混合交通流环境下高速公路基本路段通行能力,需针对车流量、网联自动驾驶车辆(CAV)比例制定与之匹配的车道管理策略。针对低CAV比例环境下CAV专用车道闲置浪费的问题,提出了一种CAV优先车道管理策略。利用跟驰模型推导了混合... 为提高网联混合交通流环境下高速公路基本路段通行能力,需针对车流量、网联自动驾驶车辆(CAV)比例制定与之匹配的车道管理策略。针对低CAV比例环境下CAV专用车道闲置浪费的问题,提出了一种CAV优先车道管理策略。利用跟驰模型推导了混合交通流基本图模型,构建了人工驾驶车辆(HV)专用车道、CAV专用车道、混行车道及CAV优先车道通行能力模型,分析了高速公路不同车道组合方案适用的交通需求范围。然后,以双向4车道高速公路为例,基于SUMO仿真平台分析了CAV优先车道性能,对不同车道组合方案的通行能力和适用范围进行了仿真验证,并从效率、安全及能耗角度对车道组合方案进行了比较。结果表明:在适用性方面,CAV比例p≤0.5时,两条混行车道适用的交通需求范围最大,CAV优先车道次之,CAV专用车道最小;在效率方面,p≤0.5时,设置CAV专用车道方案的效率最差,CAV优先车道表现较好,且p越小优先车道效率提升越显著;在安全、能耗方面,设置CAV专用车道方案的能耗和安全性能较佳,CAV优先车道次之;在p>0.5时,设置CAV专用车道方案的综合表现更优;在多种车道管理方案均可行时,相比于两条混行车道方案,采取其他车道管理措施在安全、能耗上的表现均有提升;在需求D≤2500 veh/h,p≤0.5时,相比于其他车道方案,采用CAV优先车道方案既能满足通行需求、降低能耗,也能更充分地利用道路资源,综合表现均衡。 展开更多
关键词 智能交通 车道管理策略 通行能力分析 CAV优先车道 混合交通流
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考虑电动汽车优先级需求的两阶段优化调度策略 被引量:2
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作者 崔明勇 吕静 +1 位作者 薛思嘉 曹朋 《电工电能新技术》 CSCD 北大核心 2024年第4期20-28,共9页
随着光伏发电渗透率的升高,光伏出力的不确定性会影响电网的安全稳定运行。而利用电动汽车(EV)移动储能的特性可以实现EV和光伏的协同增效。本文基于EV能量调度的灵活性,构建了考虑用户充电需求的EV两阶段优化调度模型:在日前预调度阶段... 随着光伏发电渗透率的升高,光伏出力的不确定性会影响电网的安全稳定运行。而利用电动汽车(EV)移动储能的特性可以实现EV和光伏的协同增效。本文基于EV能量调度的灵活性,构建了考虑用户充电需求的EV两阶段优化调度模型:在日前预调度阶段,建立光伏的就地消纳偏差最小、EV充电完成率最大、EV用户出行成本最小的多目标优化函数,并引入充放电系数对EV的充电行为进行优化;在实时调度阶段,负荷聚合商结合各时段EV的实际充电需求,根据调度优先级对优化后的充放电系数修正,保证EV充电的公平性,制定出最优的充放电策略。通过综合考虑EV用户对于充电完成度和充电成本的不同需求,对不同充电模式、不同权重系数进行分析,同时考虑了用户改变充电需求的情况,验证本文所提策略在降低光伏消纳偏差量、满足用户充电需求方面具有明显效果。 展开更多
关键词 电动汽车 充电需求 调度优先级 就地消纳
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基于公交优先的干线协调信号控制改进模型 被引量:2
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作者 赵欣 李瑞 酆磊 《重庆交通大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第1期67-74,98,共9页
基于公交信号优先策略,对MULTIBAND模型进行改进,重新定义了权重系数、车道清空时间和最小绿波带宽,结合不同相位放行方式实施红灯早断或绿灯延长控制策略,并在此基础上考虑公交车辆的车速与停靠时间,建立对公交车辆的约束,提出基于公... 基于公交信号优先策略,对MULTIBAND模型进行改进,重新定义了权重系数、车道清空时间和最小绿波带宽,结合不同相位放行方式实施红灯早断或绿灯延长控制策略,并在此基础上考虑公交车辆的车速与停靠时间,建立对公交车辆的约束,提出基于公交优先的干线协调信号控制改进模型。通过VISSIM仿真,将该模型与传统干线协调信号控制模型对比分析,结果表明:与传统协调控制模型相比,模型使社会车辆平均延误降低了4.77%,停车次数降低了3.77%,公交车辆平均延误降低了11.35%,停车次数降低了2.06%,人均延误降低了7.22%,且在不同的公交流量下均有较好的效果。 展开更多
关键词 交通运输工程 公交优先 干线协调信号控制 MULTIBAND 绿波控制
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抢占式调度问题的PPTA模型与验证方法
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作者 左正康 赵帅 +2 位作者 王昌晶 谢武平 黄箐 《软件学报》 EI CSCD 北大核心 2024年第10期4533-4554,共22页
优先级用于解决诸如在资源共享和安全设计等方面的冲突,已经成为实时系统设计中不可或缺的一部分.对于引入优先级的实时系统,每个任务都会被分配优先级,这就导致低优先级的任务在运行时可能会被高优先级的任务抢占资源,进而给实时系统... 优先级用于解决诸如在资源共享和安全设计等方面的冲突,已经成为实时系统设计中不可或缺的一部分.对于引入优先级的实时系统,每个任务都会被分配优先级,这就导致低优先级的任务在运行时可能会被高优先级的任务抢占资源,进而给实时系统带来抢占式调度问题.现有研究,缺乏一种可以直观表示任务的优先级以及任务之间的依赖关系的建模及自动验证方法.为此,提出抢占式优先级时间自动机(PPTA)并引入抢占式优先级时间自动机网络(PPTAN).首先,通过在时间自动机上添加变迁的优先级来表示任务的优先级,再利用变迁将具有依赖关系的任务相关联,从而可以利用PPTA建模带有优先级的实时任务.在时间自动机上添加阻塞位置,进而利用PPTAN建模优先级抢占式调度问题.其次,提出基于模型的转换方法,将抢占式优先级时间自动机映射到自动验证工具UPPAAL中.最后,通过建模多核多任务实时系统实例并与其他模型进行对比,说明所提模型不仅适用于建模优先级抢占式调度问题并可对其进行准确验证分析. 展开更多
关键词 优先级抢占式调度 抢占式优先级时间自动机 多核多任务实时系统 UPPAAL
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河北衡水湖自然保护区水鸟多样性分布格局及其保护优先区
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作者 郭子良 张余广 +2 位作者 刘魏魏 张曼胤 刘振杰 《生态学报》 CAS CSCD 北大核心 2024年第9期4009-4019,共11页
水鸟是反映湿地生态系统状况的指示物种,水鸟多样性保护优先区识别对自然保护区功能区划和湿地保护修复具有重要意义。于2020年5月—2021年4月,开展了衡水湖自然保护区水鸟群落的调查监测,采用GIS软件和结构方程模型等分析其不同区域水... 水鸟是反映湿地生态系统状况的指示物种,水鸟多样性保护优先区识别对自然保护区功能区划和湿地保护修复具有重要意义。于2020年5月—2021年4月,开展了衡水湖自然保护区水鸟群落的调查监测,采用GIS软件和结构方程模型等分析其不同区域水鸟群落结构和季节性变化、水鸟多样性分布格局及其驱动因素。结果表明:(1)衡水湖自然保护区不同区域均表现出以雁鸭类等游禽为优势种的水鸟群落特征,衡水湖西湖和滏东排河的水鸟物种丰富度和Shannon多样性指数最高,衡水湖东湖的水鸟种群数量最大,滏阳新河的鸻鹬类种群数量相对较大。(2)不同区域水鸟群落具有明显的季节性变化特征,春夏季涉禽数量明显增多,但仅在衡水湖自然保护区东湖、西湖和滏阳新河成为水鸟群落的优势种;9月之后各区域游禽种数和种群数量占比均明显上升,雁鸭类成为优势种群。(3)水鸟物种丰富度和种群数量较高的区域主要在自然保护区的湿地恢复区、滏东排河和小湖隔堤两侧等地;不同类群水鸟的空间分布格局差异较大,雁鸭类分布较为分散,鸻鹬类、鹤鹳类水鸟分布更为集中;栖息地状况是影响衡水湖水鸟多样性的主要因素。(4)衡水湖水鸟保护优先区包括湿地恢复区及周边区域、南李庄鱼塘、良心庄鱼塘及周边区域、东湖的姊妹东岛、小湖隔堤两侧等5个区域,占保护区总面积的8.94%。研究结果为衡水湖自然保护区的功能区划、水鸟保护策略制定、栖息地保护修复提供了相关依据。 展开更多
关键词 鸟类 分布格局 保护优先区 衡水湖
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