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An Approximation Algorithm for P-prize-collecting Set Cover Problem

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Journal of the Operations Research Society of China 2023年第1期11卷 207-217页

作者： Jin-Shuang guo Wen Liu bo Hou School of Mathematical Sciences Hebei Key Laboratory of Computational Mathematics and ApplicationsHebei Normal UniversityShijiazhuang050024HebeiChina

In this paper,we consider the P-prize-collecting set cover(P-PCSC)problem,which is a generalization of the set cover *** this problem,we are given a set system(U,S),where U is a ground set and S⊆2U is a collection of subsets satisfying∪S∈SS=*** subset in S has a nonnegative cost,and every element in U has a nonnegative penalty cost and a nonnegative *** goal is to find a subcollection C⊆S such that the total cost,consisting of the cost of subsets in C and the penalty cost of the elements not covered by C,is minimized and at the same time the combined profit of the elements covered by C is at least P,a specified profit *** main work is to obtain a 2f+ε-approximation algorithm for the P-PCSC problem by using the primal-dual and Lagrangian relaxation methods,where f is the maximum frequency of an element in the given set system(U,S)andεis a fixed positive number.

关键词： P-prize-collecting set cover problem Approximation algorithm Primal-dual Lagrangian relaxation

Characteristics of Solute Transport Continuously Released from Coastal Unconfined Aquifers under the Tidal Action Based on Laboratory Experiment

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Journal of Earth Science 2024年第5期35卷 1738-1748页

作者： min guo Junwei Wan Kun Huang Hubei Key Laboratory of mine Environmental Pollution Control and Remediation Hubei Polytechnic UniversityHuangshi435003China School of Environmental Studies China University of GeosciencesWuhan 430074China

Most studies on solute transport in coastal aquifers affected by tides focus on the transport of instantaneous released solute,and there are few studies on continuously released solute affected by *** this study,the image monitoring method is used to establish the quantitative relationship between the concentration of the colored tracer and the hue value of the image,and the digital image is used to determine the tracer concentration *** image monitoring method laboratory experiments,quantitative analysis of the characteristics of continuously released solute transport in coastal unconfined aquifers under the tidal *** show that the high tide inhibits the increase in the concentration of each point in the *** the influence of tides,the solute plume retreats towards the *** the low tide period,the solute plume migrates toward the sea *** the solute plume will maintain a relatively stable shape after entering the aquifer for a long enough *** the tidal effect seems to have little effect on the estimation of the position of the solute plume,but ignoring the tidal effect has a certain influence on the estimation of the dispersion range of the solute *** matter whether considering the tidal action,the final dispersion range of the solute plume is almost the *** before the solute plume reaches a stable state,ignoring the tidal effect will lead to a smaller dispersion range of the solute plume.

关键词： tidal action coastal unconfined aquifers continuously released solute solute transport image monitoring method marine geology

Applicability of anoxic-oxic process in treating petrochemical wastewater

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第1期10卷 133-141页

作者： Li-jun ZHAO Fang MA Jing-bo guo School of Chemical Engineering China University of Petroleum Beijing 102249 China School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150090 China

To explore the applicability of anoxic-oxic (A/O) activated sludge process for petrochemical wastewater treatment,the relationship between bacterial community structure and pollutants loading/removal efficiencies was investigated by gas chromatograph-mass spectrometry (GC-MS),polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and other conventional *** showed that when the concentrations of the influent chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N) were 420～560mg/L and 64～100mg/L,respectively,the corresponding average effluent concentra-tions were 160mg/L and 55mg/L,which were 1.6 and 2.2times higher than those of the national standards in China,respectively,demonstrating the inefficient performances of A/O *** of GC-MS indicated that refractory pollutants were mainly removed by sludge adsorption,but not by ***-DGGE profile analysis suggested that the biological system was species-rich,but there was apparent succession of the bacterial community structure in different locations of the A/O *** of bacterial community structure and pollutant loadings had obvious influences on pollutants removal ***,A/O process was inapplicable for the treatment of complicated petrochemical wastewater,and strategies such as the reinforcement of pre-treatment and two-stage A/O process were suggested.

关键词： Petrochemical wastewater Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) Anoxic-oxic (A/O) process Applicability

Three dimensional K-Tz stress fields around the embedded center elliptical crack front in elastic plates

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Acta Mechanica Sinica 2006年第2期22卷 148-155页

作者： Junhua Zhao Wanlin guo Chongmin She bo Meng eng Institute of Nano Science Nanjing University of Aeronautics Astronautics Nanjing 210016 China

Through detailed three-dimensional （3D） finite element （FE） calculations, the out-of-plane constraints Tz along embedded center-elliptical cracks in mode I elastic plates are studied. The distributions of Tz are obtained near the crack front with aspect ratios （a/c） of 0.2, 0.4, 0.5, 0.6, 0.8 and 1.0. Tz decreases from an approximate value of Poisson ratio v at the crack tip to zero with increasing normalized radial distances （r/a） in the normal plane of the crack front line, and increases gradually when the elliptical parameter angle φ changes from 0° to 90°at the same r/a. With a/c rising to 1.0, Tz is getting nearly independent of φ and is only related to r/a. Based on the present FE calculations for Tz, empirical formulas for Tz are obtained to describe the 3D distribution of Tz for embedded center-elliptical cracks using the least squares method in the range of 0.2 ≤ a/c ≤ 1.0. These Tz results together with the corresponding stress intensity factor K are well suitable for the analysis of the 3D embedded centerelliptical crack from field, and a two-parameter K-Tz principle is proposed.

关键词： Three-dimensional finite element Out-of-plane constraint Tz Embedded elliptical crack Stress intensity factor T-Stress Stress field

Vibration response and safety control for blasting vibration of the existing tunnel with defects

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Underground Space 2024年第2期15卷 76-89页

作者： Junying Xia bo Wang Xinxin guo Zhuoxiong Xie Key Laboratory of Transportation Tunnel Engineering Ministry of EducationSouthwest Jiaotong UniversityChengdu 610031China College of Environment and Civil Engineering Chengdu University of TechnologyChengdu 610059China Guangdong Communication Planning&Design Institute Group Co. LtdGuangzhou 510507China

Current studies on blasting construction of small clear-distance tunnels have not considered the impact of existing tunnel lining defects when establishing safety *** paper offers a series of study results based on the blasting project of a new tunnel adjacent to the existing defect Xinling tunnel to thoroughly examine the dynamic response,safety control standards,and measures of the existing defect ***,structural models were developed to investigate the influence of the presence or absence of specific defects(like lining cracks and cavities behind the lining)on the dynamic response of the current tunnel lining to identify the most unfavorable defect ***,establish safety control standards for intact linings and those with the most unfavorable ***,two types of control measures,single safe charge and reasonable delay time,were studied based on the established safety control *** particular,the most adverse position of cracks was the wall facing the explosion,the rise in depth was more unfavorable for vibration response,and the impact of the longitudinal crack was restricted to the vicinity of the *** the vault was the most adverse cavity position,the rise in cavity area was more damaging,and the influence range varied with longitudinal cavity ***,the impact of cracks was mainly evident in the amplification effect of stress at the crack *** contrast,cavities had varied degrees of amplification effects on the vibration velocity and stress response and a relatively extensive influence *** control research was conducted,when the tunnel was intact,with a right wall crack,a vault cavity,and both vault cavity and crack for this project,the peak particle velocity(PPV)of the safety control standard for vibration velocity was 13,10,13,and 8 cm/s,respectively,and the respective single safe charge could be adjusted at 64,53,37,and 25 ***,the presence of different defects had a relati

关键词： Existing tunnel Defect Blasting construction Vibration response Control standards and measures

Collaborative optimization of maintenance and spare ordering of continuously degrading systems

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Journal of Systems Engineering and Electronics 2012年第1期23卷 63-70页

作者： Wei Zhou Dongfeng Wang Jingyu Sheng bo guo College of Information System and Management National University of Defense Technology Changsha 410073 P. R. China Beijing Special Engineering Design and Research Institute Beijing 100028 P. R. China

A collaborative optimization model for maintenance and spare ordering of a single-unit degrading system is proposed in this paper based on the continuous detection. A gamma distribution is used to model the material degradation. The degrading decrement after the imperfect maintenance action is assumed as a random variable normal distribution. This model aims to ob- tain the optimal maintenance policy and spare ordering point with the expected cost rate within system lifecycle as the optimization objective. The rationality and feasibility of the model are proved through a numerical example.

关键词： collaborative optimization maintenance spare order- ing degrading system.

Solving resource availability cost problem in project scheduling by pseudo particle swarm optimization

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Journal of Systems Engineering and Electronics 2014年第1期25卷 69-76页

作者： Jianjun Qi bo guo Hongtao Lei Tao Zhang School of Information System and Management National University of Defense Technology

This paper considers a project scheduling problem with the objective of minimizing resource availability costs appealed to finish al activities before the deadline. There are finish-start type precedence relations among the activities which require some kinds of renewable resources. We predigest the process of sol-ving the resource availability cost problem （RACP） by using start time of each activity to code the schedule. Then, a novel heuris-tic algorithm is proposed to make the process of looking for the best solution efficiently. And then pseudo particle swarm optimiza-tion （PPSO） combined with PSO and path relinking procedure is presented to solve the RACP. Final y, comparative computational experiments are designed and the computational results show that the proposed method is very effective to solve RACP.

关键词： project scheduling resource availability cost problem(RACP) heuristics particle swarm optimization (PSO) path relin-king.

Enabling entity discovery in indoor commercial environments without pre-deployed infrastructure

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Frontiers of Computer Science 2019年第3期13卷 618-636页

作者： bo YUAN Xiaolei ZHOU Xiaoqiang TENG Deke guo Science and Technology on Information Systems Engineering Laboratory National University of Defense Technology Changsha 410073 China

Finding entities of interest in indoor commercial places, such as the merchandise in supermarkets and shopping malls, is an essential issue for customers, especially when they are unfamiliar with an ad hoc indoor environment. This type of location-based indoor service requires comprehensive knowledge of indoor entities, including locations as well as their semantic information. However, the existing indoor localization approaches fail to directly localize these general entities without dedicated devices. This paper first focuses on the problem of discovering large-scale general entities of interest in indoor commercial spaces without pre-deployed infrastructure. We present a unique entity localization approach that leverages the localization results from multiple independent users to accurately determine the location of corresponding entities. Our key idea is to exploit the short-distance estimation with dead reckoning to guarantee the accuracy of entity localization. We develop a prototype system based on the crowdsourcing method, iScan, and test it in one of the biggest supermarkets in Changsha, China, to validate the performance of our design. Extensive experimental results show that our approach can achieve meter-level accuracy in a single day with 70 participants. Moreover, in a monthly evaluation with 500 effective participants, iScan discovered more than 200 entities and localized approximately 75% of them within 2 m.

关键词： indoor localization entity discovery crowdsourcing system location-based service

Influence of Low-Energy Ion Irradiation on Plasma Membrane Permeability of Cells

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Chinese Physics Letters 2000年第1期17卷 61-63页

作者： ZHANG Dong-Mei CUI Fu-Zhai SUN Su-Qin LIN You-bo TIAN min-bo CHEN guo-Qiang Department of Materials Science and Engineering Tsinghua UniversityBeijing 100084 Analysis Center Tsinghua UniversityBeijing 100084 Department of Biological Science and Biotechnology Tsinghua UniversityBeijing 100084

Effect of low-energy ion irradiation on plasma membrane permeability has been investigated by using electron spin resonance(ESR)spectroscopy of spin probe *** investigated system is plumule cells of wheat(Triticum aestivum L.)seeds implanted by 30 keV N^(+) *** spectra indicated that plasmalemma permeability is sensitive to low-energy ion *** irradiations with increasing Huences up to semi-lethal dose lead to gradual increase in plasmalemma permeability of the plumule *** possible factors relevant to the changes in membrane permeability are discussed in relation to the changes in the physical state and chemical nature of membranes.

关键词： technique. permeability irradiation