OALib Journal期刊

ISSN: 2333-9721




2018 ( 2 )

2017 ( 57 )

2016 ( 92 )

2015 ( 1083 )


匹配条件: “ Junwen Zhou” ,找到相关结果约32513条。
Performance Evalution Analysis for College Teachers Based on Weighted Idealpoint
Shuangxi ZHOU,Junwen FENG
Management Science and Engineering , 2012, DOI: 10.3968/j.mse.1913035x20120602.2200
Abstract: The evaluation methods of college teachers’ performance should be scientific and feasible. To accomplish this goal, we design the performance evaluation index system from three aspects as teaching, scientific research and professional disciplines development. By using the principal component analysis method we reduce the data dimension, through combining with the weighted idealpoint method, we get the final ranking result. Finally, an example is given to show the rationality and effect of the evaluation method. Key words: College teachers; Performance evaluation method; Principal component analysis method; Weighted ideal-point method
Impacts of the Fukushima nuclear accident on the China Seas: Evaluation based on anthropogenic radionuclide 137Cs
JunWen Wu,KuanBo Zhou,MinHan Dai
Chinese Science Bulletin , 2013, DOI: 10.1007/s11434-012-5426-2
Abstract: In order to evaluate the impact of the Fukushima nuclear accident on the China Seas, seawater samples from the South China Sea (SCS), the East China Sea (ECS) and the Yellow Sea (YS) were collected in April–June 2011, and their 137Cs activities were measured using low-background γ-spectrometry. 137Cs activities in the study area ranged from 0.75±0.07 to 1.43±0.08 Bq m 3 with an average of 1.12±0.08 Bq m 3. 137Cs activities initially increased from the nearshore to the inner shelf, and subsequently decreased from the inner shelf to the outer shelf. Vertical profiles showed higher 137Cs activities at the surface but lower activities at depth in the ECS, suggesting atmospheric input of 137Cs. As such, the distribution pattern of 137Cs in the region was presumably determined by a combination of atmospheric deposition and subsequent mixing between different water masses including the coastal currents, the Yangtze River plume and the Taiwan Warm Currents. Based on the inventory of 93 Bq m 2 and the atmospheric deposition flux of 137Cs in the ECS of 32.2 mBq m 2 d 1 (5.4–42.9 mBq m 2 d 1) which we estimated, we derived the residence time of 137Cs in the upper water column to be 66 d (45–95 d). We concluded that in terms of 137Cs, the ECS was less impacted by the Fukushima accident as compared to the Chernobyl accident. The released amount of 137Cs into the ECS from the Fukushima accident was minute.
Design of Drive System for Sensorless Brushless DC Motor Based on Model Reference Adaptive Control and Its Application in Horizontal Well Tractor  [PDF]
Zhou He, Yongjun Chen, Bo Ruan, Shuhan Yu, Junwen Zhou
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104267
The actual working environment temperature of the horizontal well tractor is too high, which leads to position sensor of general brushless DC motor (BLDCM) cannot work normally. Therefore, the position sensorless drive system is designed to overcome the problems caused by the position sensor in the actual working conditions. The principle of sensorless BLDCM work is introduced in detail, And drive system of Sensorless BLDCM was established by using simulation software. The use of three stage start make motor smoothly start, the motor speed detection based on model reference adaptive control (MRAC), ensures accurate commutation. Finally, the hardware and software design of the BLDCM system based on digital signal controller (DSC) is introduced and tested. The experimental results show that the drive system can start the BLDCM smoothly in the high temperature environment, and can quickly track the given speed, which meet the actual work demand of the horizontal well tractor.
Research on Permanent Magnet Synchronous Motor Driver System of Horizontal Well Tractor  [PDF]
Zhou He, Yongjun Chen, Shuhan Yu, Junwen Zhou, Yang Shen, Kuan Shi
Open Access Library Journal (OALib Journal) , 2017, DOI: 10.4236/oalib.1104237
Nowadays, horizontal well technology is being applied to the development of oilfield production capacity more and more. The horizontal well tractor can effectively solve the problem that the instrument can not get to the target layer by gravity. However, in actual conditions, Brushless DC motor (BLDCM) there is a large torque ripple problem, resulting in motor running is not smooth, vibration and noise is too large, can not meet the demand. Therefore, propose horizontal well tractor PMSM sine wave drive technology. The paper discusses the mathematical model of permanent magnet synchronous motor, analyzes the working principle of space vector pulse width modulation (SVPWM) technology, and establishes a speed and current double closed-loop space vector control system of the permanent magnet synchronous motor by using PSIM simulation software. Simulation results verify the robustness of the control system, and the torque ripple of the motor is small, in line with the working conditions of horizontal well tractor.
A Study on Competence Sets Expansion Facing on Engineering Management Decision
Junwen FENG
Management Science and Engineering , 2012, DOI: 10.3968/j.mse.1913035x20120604.581
Abstract: Engineering management decision making is a complicated system problem whose traits are multiple persons and multiple objective. There are much uncertain influence factors during its decision making process which requires decision-makers and participants expanding their competence set. Competence set expansion refers to decision-makers and participants to make decision of expanding from the obtained competence set to the required one of resolving problem on a particular issue in a limited time. This paper establishes the multiple persons and multiple objective competences set expansion model combining with the traits of engineering management decision making, it can lay a necessary theoretical foundation of research on engineering management decision making and analysis problem. Key words: Decision model; Multi-person and multi-objective; Competence set expansion
Competence System Management
Junwen FENG
Management Science and Engineering , 2012, DOI: 10.3968/j.mse.1913035x20120604.feng2
Abstract: Competence Set Analysis is a managerial decision analysis theory proposed and studied in 1980’s by the distinguished Professor Po-Lung Yu of Management Science, USA. In this paper, the recent research results in this field and its applications are reviewed, including behavior and decision mechanism, behavior hypotheses, common behavior tendencies, habitual domains analysis, competence set analysis, competence system management, etc.. Finally, further possible extensions and research problems are discussed. Key words: Decision analysis; Competence set analysis; Habitual domain; Behavior pattern; Competence system management
Competence Sets Expansion Based on the Fuzzy Rough Neural Network
Junwen FENG
International Business and Management , 2012, DOI: 10.3968/j.ibm.1923842820120502.1100
Abstract: Traditional competence sets analysis focuses on the expansion of the discrete competence sets, and focus on the uncertainty analysis. By means of uncertainty reasoning techniques and principles (probability reasoning, evidential reasoning, fuzzy reasoning, information reasoning, including degree reasoning, etc.), how to study competence expansion under uncertain circumstances, that is one of the issues of competence expansion theory. About competence expansion question under the indefinite situation, papers formerly mainly studied that the enterprise’s obtained competence or actual requisite competence is indefinite, did not solve that both are indefinite, precisely based on this goal, this article studies the enterprise competence expansion process under this kind of situation by using the fuzzy rough neural network method, solves fuzzy market demand and rough technology competence and so on uncertainty influence factors, helps decision-maker to expand enterprise technology competence to the needed technology competence of enterprise technology innovation question satisfaction solution. Key words: Enterprise management decision; Fuzzy rough neural network; Competence sets expansion
Acute Thoracic Aortic Dissection (Stanford Type B) Complicated with Acute Renal Failure
Li Li,ShunJiu Zhuang,ShaoHong Qi,JiaSheng Cui,JunWen Zhou,Huaqi Zhu,Wan Zhang,Ming Li,Weiguo Fu
Case Reports in Vascular Medicine , 2013, DOI: 10.1155/2013/693435
Abstract: We report a recent case and review some literatures of acute aortic dissection (AAD) Stanford type B complicated with late onset of acute renal failure. The patient underwent preoperational peritoneal dialysis followed by thoracic endovascular aortic repair (TEVAR) and was fully recovered and discharged soon after surgery. We conclude that an AAD case is difficult to achieve a timely diagnosis, but with attention to systemic symptoms and dedication thorough treatment plan, a full recovery and positive prognosis are expected. 1. Case Report A 51-year-old male patient was transferred to our unit with a diagnosis of acute thoracic aortic dissection. He had experienced sudden onset excruciating chest-back “tearing” pain with nonspecific ST change for 3 hours after myocardial infarction was ruled out by the cardiac care unit. Upon admission, physical examination showed BP 200/110?mmHg with HR 92; femoral artery was palpable bilaterally. Patient did not have a medical history of hypertension or diabetes and lab testing showed nothing remarkable. As per computed tomography angiography (CTA), the initial rupture in thoracic aorta was located 2?mm distal from the left subclavian artery (LSA), (Figure 1) with dissection extending down to the branch of abdominal aorta and partial involvement of left iliac artery; bilateral renal arteries were both opened to true lumen; celiac trunk opened partially to true lumen; inferior mesenteric artery opened to false lumen; the inner diameter of aortic arch was 31.9?mm. Thus, Stanford type B aortic dissection was confirmed. Figure 1: CTA image shows the location of tear in thoracic aorta (arrow). Initial medical management was symptomatic, focusing on controlling blood pressure and heart rate, sedation, and pain relief along with a frequent monitoring schedule to evaluate patient’s hemodynamic change, peripheral vascular change, and mental status. Patient was stabilized soon with blood pressure down to 120/75?mmHg. However, four days later, the patient started experiencing increasing chest-back pain, accompanied by ongoing oliguria (from 900?mL/24?hr to 350?mL/24?hr), anuria, facial edema, and agitation; lab testing found that BUN went up to 30.1?mmol/L and creatinine to 710?nmol/L. Acute ischemic renal failure was given the nature of urgency, the peritoneal dialysis was performed immediately. Within 24?hrs, patient’s symptoms and hemochemistry were stabilized, and TEVAR was performed under epidural anaesthesia. A pigtail catheter was inserted to the beginning of the ascending aorta via right femoral artery along the lumen
Generalizations of Markov model to characterize biological sequences
Junwen Wang, Sridhar Hannenhalli
BMC Bioinformatics , 2005, DOI: 10.1186/1471-2105-6-219
Abstract: We describe a configurable tool to explore generalizations of the standard Markov model. We evaluated whether the sequence classification accuracy can be improved by using an alternative set of model parameters. The evaluation was done on four classes of biological sequences – CpG-poor promoters, all promoters, exons and nucleosome positioning sequences. Using di- and tri-nucleotide as the model unit significantly improved the sequence classification accuracy relative to the standard single nucleotide model. In the case of nucleosome positioning sequences, optimal accuracy was achieved at a gap length of 4. Furthermore in the plot of classification accuracy versus the gap, a periodicity of 10–11 bps was observed which might indicate structural preferences in the nucleosome positioning sequence. The tool is implemented in Java and is available for download at ftp://ftp.pcbi.upenn.edu/GMM/ webcite.Markov modeling is an important component of many sequence analysis tools. We have extended the standard Markov model to incorporate joint and long range dependencies between the sequence elements. The proposed generalizations of the Markov model are likely to improve the overall accuracy of sequence analysis tools.Biological complexity has evolved through a combination and interactions between simpler units. By looking at these units in a context dependent way, we can better understand the biological complexity. For example, Wang and Feng explored the amino acid propensity pattern in a neighbor-dependent way and found that the patterns were not always predictable from the single amino acid patterns [1]. Application of these di-amino acid propensity patterns into a traditional Needleman-Wunsch [2] algorithm significantly improved protein sequence alignment [3]. Similarly one can better predict the transcription factor binding sites by considering the interdependence between nucleotides [4,5].Markov model (MM) is a statistical technique to model sequences such that the probab
An Overview Study on Dornbusch Overshooting Hypothesis
Wenwen Tu,Junwen Feng
International Journal of Economics and Finance , 2009, DOI: 10.5539/ijef.v1n1p110
Abstract: Thirty years have passed since Dornbusch first published his overshooting hypothesis on “Expectations and Exchange Rate Dynamics”. Reviewing and appraising the advantages and disadvantages of this elegant model in international economics is of great importance to the consideration of establishing exchange rate and macro-economic policy in the future. In this paper, the author provides an analysis and empirical evidence for and against this influential model. Some conclusions are drawn from an all-sided discussion.

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