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1.
HAN Shu-guang JIANG Yi-wei HU Jue-liang 《浙江大学学报(A卷英文版)》2007,8(1):127-133
INTRODUCTION In this paper we investigate the uniform ma-chines scheduling problem with machine activationcost. This problem has application in garment pro-duction of international trade and is motivated by thefollowing scenario. Import-export company is com-pared to scheduler in this model, and orders are jobs,which arrive one by one. And garment factories canbe regarded as machines. Since jobs should be fin-ished on time, scheduler will choose a reasonablenumber of machines to make the… 相似文献
2.
In this paper, a semi on-line version on m identical machines M1, M2, …,Mm(m≥3) was considered, where the processing time of the largest job is known in advance. Our goal is to maximize the minimum machine load, an NPLS algorithm was presented and its worst-case ratio was proved to be equal to m-1 which is the best possible value. It is concluded that if the total processing time of jobs is also known to be greater than (2m-1)pmax where pmax is the largest job's processing time, then the worst-case ratio is 2-1/m. 相似文献
3.
以旅行者的旅行时间最短为优化目标,用竞争分析的方法考虑了自然灾害环境中的在线导航问题,提出了旅行者在受灾区行走的上界控制策略,通过竞争比和竞争性能分析,结果表明上界控制策略具有该问题最优竞争比2k＋1,并且竞争性能得到了提高． 相似文献
4.
研究了工件有尺寸大小的一致性在线分批排序．就所有工件有两个到达时间ri,i=1,2(不妨设r1=0,r2=r)对于0时刻到达的工件中加工时间最大的批满足一定的约束条件下的一致性在线分批排序给出一个在线算法,并证明了算法的竞争比不超过2．357． 相似文献
5.
A single machine scheduling problem involving fuzzy due dates and fuzzy precedence constraints is investigated. The fuzzy precedence reflects the satisfaction level with respect to precedence between two jobs. A membership function is associated with each job Ji, which describes the degree of satisfaction with respect to completion time of Ji. For the bi-criteria scheduling problem, an 0 （ n^3 ） algorithm is proposed for finding nondominated solutions. 相似文献
6.
Lucia Mýtna Kureková Miroslav Beblavý Corina Haita Anna-Elisabeth Thum 《Journal of Education & Work》2016,29(6):662-687
This article analyses online job advertisements to identify skills that are demanded in selected low- and medium-skilled occupations. We explore data from the publicly administered cross-European EURES job search portal and quantify the different cognitive and non-cognitive skills requested by employers in small European economies. While we find that the service sector demands non-cognitive skills more than other types of occupation, the skill-mix demanded is very diverse across countries, implying that other domestic factors shape how demand is formulated. Our work shows that online portals can become a useful source for studying employers’ demand at the micro-level to inform employment, education and training policies. 相似文献
7.
Rachel L. Bissett Michael S.H. Cheng Robert G. Brannan 《Journal of Food Science Education》2010,9(1):11-18
ABSTRACT: Professional organizations have linked core competency to professional success and competitive strategy. The Research Chefs Assn. (RCA) recently released 43 core competencies for practicing culinologists. Culinology® is a profession that links skills of culinary arts and food science and technology in the development of food products. An online survey was created asking RCA members from all 6 membership categories (Associate, Affiliate, Chef, Culinology, Food Science and Technology (FS&T), and Student) to rate their knowledge level based on a 7‐point scale and agreement to importance in job performance based on a 5‐point Likert scale for each competency statement. RCA participant's (N = 192) survey results were analyzed using SPSS for Windows version 13.0 at a significance level of P < 0.05. Statistical survey validation grouped all 43 competency statements into 8 factors (groupings) according to level of competency proficiency (opposed to the 7 groups each competency was originally designated by the RC A) and into 9 factors according to job success. Results suggest that Chef Members know “Culinary Arts” best and FS&T members know “Food Science” best. A gap analysis determined what competency factors were low in knowledge level yet important to job success for each membership category. Chef members have a lower level of knowledge in “Product Development,”“Food Science,” and “Quality Assurance” factors; however, the factors are important to job success. FS&T members have a lower level of knowledge in “Nutrition” yet identified the factor important to job success. An opportunity exists to improve educational efforts for specific membership categories. 相似文献
8.
In this paper, we propose a novel optimal quality adaptation algorithm for MPEG-4 fine granular scalability (FGS) stream over wired network. Our algorithm can maximize perceptual video quality by minimizing video quality variation and increasing available bandwidth usage rate. Under the condition that the whole bandwidth evolution is known, we design an optimal algorithm to select layer. When the knowledge of future bandwidth is not available, we also develop an online algorithm based on the optimal algorithm. Simulation showed that both optimal algorithm and online algorithm can offer smoothed video quality evolution. 相似文献
9.
In this paper, we propose a novel optimal quality adaptation algorithm for MPEG-4 fine granular scalability (FGS) stream over wired network. Our algorithm can maximize perceptual video quality by minimizing video quality variation and increasing available bandwidth usage rate. Under the condition that the whole bandwidth evolution is known, we design an optimal algorithm to select layer. When the knowledge of future bandwidth is not available, we also develop an online algorithm based on the optimal algorithm. Simulation showed that both optimal algorithm and online algorithm can offer smoothed video quality evolution. 相似文献
10.
Lim Lee Hean 《Educational Research for Policy and Practice》2003,2(3):215-221
Findings of a study on the practice of school management learned through mentoring reveal that leading surfaced prominently
as the prime aspect of what could be learned through formal mentoring and could be put into practice on the job. These principals,
who have the opportunity to learn through mentoring, suggest their learning and practice of leading primarily through relating
with people. The three features involved are: leading through relating with people actively, promoting trust in relating with
people, and serving as worthy models in their dedication to service. As such, the learning of leading through formal mentoring
could be of significance in the professional development of aspiring principals. It highlights a known practice of leading,
learned through leadership mentoring, for an unknown future.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
11.
混部负载是当前业界提高数据资源利用率的重要手段,其原理是将在线负载和离线负载共同放置于同一数据中心、共享资源,在保证在线负载服务质量的前提下,将空闲资源分配给离线负载。当前针对混部负载中离线负载的资源调度采用传统的公平或者短作业优先等策略,并未考虑在线负载资源需求波动对离线负载运行的影响。为了达到进一步提升资源利用率和作业吞吐率的目的,提出基于负载完成时间预判的模拟退火资源分配策略。结果表明,该策略比公平策略和短作业优先策略在平均资源利用率上分别提高了7.8%和15.5%,在吞吐率上分别提高了38.2%和29.1%。 相似文献
12.
This article concerns the simultaneous assessment of DIF for a collection of test items. Rather than an average or sum in which positive and negative DIF may cancel, we propose an index that measures the variance of DIF on a test as an indicator of the degree to which different items show DIF in different directions. It is computed from standard Mantel-Haenszel statistics (the logodds ratio and its variance error) and may be conceptually classified as a variance component or variance effect size. Evaluated by simulation under three item response models (IPL, 2PL, and 3PL), the index is shown to be an accurate estimate of the DTF generating parameter in the case of the 1PL and 2PL models with groups of equal ability. For groups of unequal ability, the index is accurate under the I PL but not the 2PL condition; however, a weighted version of the index provides improved estimates. For the 3PL condition, the DTF generating parameter is underestimated. This latter result is due in part to a mismatch in the scales of the log-odds ratio and IRT difficulty. 相似文献
13.
Parallel machine scheduling problems, which are important discrete optimization problems, may occur in many applications. For example, load balancing in network communication channel assignment, parallel processing in large-size computing, task arrangement in flexible manufacturing systems, etc., are multiprocessor scheduling problem. In the traditional parallel machine scheduling problems, it is assumed that the problems are considered in offline or online environment. But in practice, problems are often not really offline or online but somehow in-between. This means that, with respect to the online problem, some further information about the tasks is available, which allows the improvement of the performance of the best possible algorithms. Problems of this class are called semi-online ones. In this paper, the semi-online problem P2|decr|lp (p＞1) is considered where jobs come in non-increasing order of their processing times and the objective is to minimize the sum of the lp norm of every machine's load. It is shown that LS algorithm is optimal for any lp norm, which extends the results known in the literature. Furthermore, randomized lower bounds for the problems P2|online|lp and P2|decr|lp are presented. 相似文献
14.
随着互联网快速发展和普及,网络购物逐渐深入人们的生活,而激烈的竞争也随之而来,网店商家想要保持竞争优势越来越困难。由于服务的无形性、生产与消费的同时性和易逝性等特点,决定了服务失误是不可避免的。在网络购物中,服务失误普遍存在,要进行良好的服务补救,首先要了解在网络购物中的服务补救满意度影响因素,它将帮助网络商家提供有效的服务补救策略,从而提高顾客的第二次满意和顾客忠诚度。 相似文献
15.
In this paper we consider an online scheduling of parallel jobs with preemption on identical machines, where jobs arrive over time. The objective is to minimize the makespan. For the problem that jobs have only two possible widths mj = 1 or m, we present an optimal online algorithm by using ＂temporary schedule＂. 相似文献
16.
多语种语言资源的建设原则与方法 总被引：1，自引：1，他引：0
高效率地建设多语种语言资源,为信息化条件下的语言教学提供有力支持是当前亟待解决的问题。笔者在分析多语种语言资源的类型及其特点的基础上,提出了以人机互助为主要原则的多语种语言资源建设思想,并对多语种语言资源建设中涉及的主要方法与环节进行了描述,还对未来工作进行了展望。笔者认为在语言资源建设中,要区分机器与人的不同角色,在语言资源的获取、加工、管理和使用等阶段充分发挥机器的作用,而在语言素材的选择、语言资源的挖掘与利用等方面要充分发挥人的作用,实现人机结合,将人的主要精力投放于任务指导、语言分析等知识性活动层面,而将机器工作的重点投放在指令执行、重复操作等技术性层面,从而为语言资源建设提供有效解决方案。 相似文献
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18.
教育技术是一项解决教育问题的系统技术,可用于推动教育、教学的各个层面上的改革。但二十多年来,由于认识受限,定位不当,我国这一领域的工作偏重于硬件设施建设与服务、教育媒体制作、教学方法改革等方面,且这些活动大部分在战术层面上开展,教育技术没有发挥更大的作用。当前,我们应关注在战略层面上实施教育技术,追求“效果、效率和效益”,即教育绩效,这是我国穷国办大教育的国情所要求的。战略优先,战术配合,战略战术互动,促进教育整体改革,落实科学发展观,这应成为信息化进程中我国教育技术高起点新发展的指导思想,成为我国教育技术学科知识体系构建研究的基本思路。用教育技术引领教育改革,在宏观层面上应重视需要的评估和系统规划,确保“做对的事情”;在中观层面上要推广教学系统设计,在微观层面上要加强对研究成果的运用,确保“把事情做对”。目前我国教育技术界电教人员或计算机科学人员的工作仅是教育技术的一个组成部分,教育技术也是各级教育管理者和广大教师的共同事业。 相似文献
19.
This research sets out a Perceptual-Judgemental-Reinforcement approach to job choice under conditions of complexity and uncertainty.
It investigates the claim that job choices are based on seven implicit factors: such as the specific size of the occupation,
the proportion of employees working full-time, the earnings, the job prospects, gender dominance in an occupation, the level
of unemployment in the occupation and the predominant age group in the job. Nine case studies involving choices from 25 randomly
selected advertised jobs are presented. Results indicated substantial idiosyncrasy in job choices. An individual logistic
regression analysis indicated no statistically significant influence of key labour market indicators in any of the nine case
studies. It was concluded that job choice was idiosyncratic; that individuals lacked insight into their job choices and probably
relied upon relatively few unstated cues. The findings have direct implications for the relevance of occupational information
and for key issues in the delivery of vocational guidance.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
Jessica M. Nicklin Laurel A. McNall Christopher P. Cerasoli Claire M. Varga R. J. McGivney 《The American journal of distance education》2016,30(3):167-179
Using Warner and Hausdorf’s (2009) framework, the authors empirically examined work–life balance and work outcomes among collegiate faculty teaching courses online. Quantitative and qualitative results from 138 online instructors demonstrated that basic psychological need satisfaction was related to higher levels of work–family enrichment, job satisfaction, performance, and intention to teach online courses again and lower levels of work–family conflict and stress. Work support was also related to job satisfaction, performance, and stress but was not related to work–family balance. These findings are important as universities are seeking ways to promote involvement with online education. 相似文献