An investigation of labor assignment rules in a dual-constrained job shop

One of the management decisions required to operate a dual-constrained job shop is the labor assignment rule. This study examines the effects of various labor assignment rules on the shop's performance. Eleven different labor assignment rules are simulated. A longest-queue rule and the traditional counterparts of the first-in-system, first-served, shortest operation time, job due date, critical ratio and shortest processing time dispatching rules are used to determine to which work center available workers should be transferred. Also tested are five new labor assignment rules that use an average of the priority values of all jobs in queue at a particular work center to determine whether that work center should receive the available worker.A SIMSCRIPT simulation program that models nine work centers provided the mechanism by which these rules were tested. Five dispatching rules, the counterparts of the five “traditional counterpart” labor assignment rules mentioned earlier, provided different shop environments. Also, the level of staffing of the work centers was altered to provide additional ship environments. Staffing levels of 50% and 67% were employed.The results show that none of the eleven labor assignment rules had a significant impact on shop performance. This is an important result because it implies that a manager can make the labor assignment decision based on other criteria such as ease or cost of application of the rules. These results were relatively insensitive to the shop environment, as represented by the dispatching rule and the staffing level.     

Simulation study of a closed-loop job shop

This study investigates the behavior of a job shop depicted as an integral component of a firm. A market places demands for the firm's products by dynamically evaluating the organization's quoted delivery times and actual delivery performance. The closed-loop model simulated in this study is described and the salient research results are reported. These experimental outcomes suggest that other conventional open-loop job shop studies tend to neglect important interactions with factors external to the shop itself.     

Priority dispatching with operation due dates in a job shop

This paper investigates the effects on job shop performance of setting and attempting to enforce operation due dates for jobs. It does so by comparing via simulation the performance of priority dispatching rules when employed to enforce operation due dates versus job due dates. The results indicate that operation due dates improve every conventional measure of job shop performance.     

Load-limited order release in job shop scheduling systems

This report examines the practice of using work load limits to control the release of orders to a job shop. Load limits function in the following general way. Whenever the inventory of work at a work center exceeds some critical value (its “load limit”), further release of orders which are routed to that work center are blocked from entering the shop. After the inventory is “worked off,” release of work to the shop gateways is again permitted. Load-limited order release is intuitively appealing because it appears to be a method for reducing system inventory and flow times. The practice of load limiting order release is becoming popularized by some of the recent production planning software products now on the market. A notable example is OPT. In this report, analytical results for an M/M/1 queueing model, along with existing simulation studies of multi-machine job shops are interpreted to form a theory about the effects of using load limits.The major finding here is the proposition that system flow time, inventory, and order tardiness all deteriorate to the extent that load limits introduce idle time into the schedule. Based on the arguments presented here, a very cautious approach toward the use of input control schemes for anywhere but gateway work centers would be advised. The conclusions drawn here are to a great extent arrived at by interpreting the research results of others, so there is a clear need for further research which tests these assertions in a more direct and controlled way.     

An empirical analysis of job shop dispatch rule selection

Job shop scheduling usually includes the process of selecting dispatch rules for loading shops with work. Traditionally, dispatch rules have been formed on the basis of processing time, operating time, or queueing order. A job shop scheduling model was developed to include external factors (such as due dates), internal factors (e.g., capacity), as well as influence factors (e.g., job status). Based on the model developed in this report a survey of industrial engineers, shop foremen, and production control supervisors was undertaken to determine what dispatch rules experienced job shop schedulers would select and if the selection process could be influenced by schedule conditions (status) or other organizational factors. Results suggest that schedulers may be influenced by other factors. This article suggests a model for further research with respect to job shop scheduling.     

Use of the net present value criterion in a random job shop where early shipments are forbidden

Both practitioners and researchers in the field of Operations Management have suggested that shop scheduling should be an integral component in both the strategic and tactical plans for an organization's assets. This paper examines the use of an accepted measure of return on assets, net present value (NPV), in a simulated shop scheduling environment where early shipment of jobs before their due dates is forbidden. In addition, early shipment of raw materials to the shop is also forbidden. This shop environment is consistent with the prevalent practice in industry of accepting orders only on a just-in-time basis to reduce purchased parts inventories. The NPV measure provides a means of balancing a variety of performance criteria that have been treated as separate objectives previously, including work-in-process inventory, finished goods inventory, mean flow time and mean tardiness, while also providing a means of measuring monetarily the value of various shop scheduling approaches.The NPV performance of priority scheduling rules and order release policies is measured in this research through the simulation of a random job shop under a variety of environmental conditions. It is found in a comparison of priority rules that use time-based information with those that use job value information that the Critical Ratio rule provides higher average performance than the three other rules used in the study. However, in some situations that are consistent with JIT practice, value-based priority rules also perform well. The use of a mechanism for delaying the release of jobs to each work center in the shop provided higher average NPV when shop utilization was set at a low level of 80%, while immediate release of work upon its arrival to the shop provided superior performance at a higher shop utilization level of 94%. While JIT materials delivery and costing yields higher NPV, it did not alter the relative ranking of priority rule/release policy combinations. In addition, it was found that environmental factors, including average job length, average number of tasks per job and level of tardiness penalty, resulted in greater variations in NPV performance than the institution of a JIT raw materials delivery policy.     

Research note: the influence of job grade differences in white-collar shop steward committees

Paul Blyton reports a study of patterns of behaviour from observation of sixteen white-collar shop steward committee meetings. The results show that the stewards' position in the work hierarchy influences the extent and form of their contribution within the meetings: those from senior work positions were more active than their lower grade counterparts.     

Coworker support as a double-edged sword: a moderated mediation model of job crafting,work engagement,and job performance

Abstract

This research aims to test the mediating effect of work engagement on the relationship between job crafting and job performance, as well as the moderating effects of two forms of coworker support on the job crafting–work engagement relationship. We collected survey-based data from two South Korean samples. Study 1 was conducted on 175 flight attendants. The results of Study 1 were then replicated in Study 2 wherein 181 hotel employees reported their own job crafting and work engagement, and their supervisors rated their job performance one month later. In both studies, work engagement fully mediated the relationship between job crafting and job performance. The positive association between job crafting and work engagement was more pronounced when coworker emotional support was high than when it was low. In contrast, the positive link between job crafting and work engagement was stronger when coworker instrumental support was low than when it was high. Coworker emotional and instrumental support further moderated the indirect effect of job crafting on job performance through work engagement.     

某放射性排风中心的噪声防护设计

文章针对某放射性排风中心可能出现的噪声污染,通过优化平面布置、优选工艺设备,并采取自动控制、隔声、消声、吸声、隔振降噪等措施,减少对工作人员的危害,可对类似的工程设计提供参考。     

以人为本做好思想政治工作

思想政治工作既是一门专业,也是一门科学.在新的历史时期,要做好思想政治工作就必须以人为本,紧紧围绕发展这一第一要务,以经济建设为中心,扎扎实实做好人的工作.必须坚持转变服务观念,提升思想政治工作的服务意识;必须坚持正确理论灌输,促进人们思想观念的更新与转变;必须坚持以人为本,把解决思想问题与解决实际问题相结合;必须坚持服务与改革相结合,切实做好思想观念的导向工作;必须提高职工综合素质,增强对社会主义市场经济的适应能力.只有不断的加强思想政治工作,做好五个必须,才能为进一步推进改革开放和现代化建设进程,加快和谐社会建设步伐,提供强大的精神动力和思想保证.     

Flexicurity and job satisfaction in Europe: The importance of perceived and actual job stability for well-being at work

In this paper we study the effect of a micro-level measure of flexicurity on workers' job satisfaction. To this end, using micro-data from the Eurobarometer survey, we disaggregate the sample of workers into different groups according not only to their employment contract (i.e. permanent or temporary), but also to their perceived job security, and we evaluate differences in job satisfaction between these groups. After the potential endogeneity of job type has been controlled for, the results show that what matters for job satisfaction is not just the type of contract, but mainly the perceived job security, which may be independent of the type of contract.The combination “temporary but secure job” seems preferable to the combination “permanent but insecure job”, indicating that the length of the contract may be less important if the worker perceives that s/he is not at risk of becoming unemployed. Our main conclusions are robust to the use of alternative definitions of workers' types and they generally hold within different welfare regimes and also for different aspects of job satisfaction, mainly those more related to job security.     

循环经济下的会计控制

循环经济的出现,给企业生产带来了一场革命,也对会计工作提出了新的挑战。本文阐述了循环经济与会计控制的关系,提出了循环经济对会计控制的新要求,阐述了循环经济模式下会计控制内容的扩展以及为适应循环经济的挑战,会计控制应采取的对策。     

物流运作中的有效损控

物流作业中的“损失”通常是指由于各种意外事故、火灾、偷盗或不当的库内作业造成的库存损坏所导致的非计划内开销的费用。物流中心内可能发生“损失”的范围主要有五个：作业人员的安全和健康、火灾、偷盗、产品的损坏和污染以及危险品的存储和搬运等。     

RFID在上海现代物流公司配送中心的应用

上海现代物流公司吉买盛卖场配送中心应用RFID技术,使仓储管理各环节更加可视化,为配送中心的快速高效运作提供了有力保障.     

配送中心的成本核算与控制

应用作业成本法对配送中心的成本进行核算、分析,可以明确配送中心各项作业所消耗的成本,从而为配送中心的成本核算及成本控制提供了依据。     

情绪管理在工作上的应用

理智和情感不是绝对对立的,不是非此即彼。在遵循合理的原则下,用智慧来调配、控制感情因素,有利于我们工作的顺利开展。工作上,情绪失控主要由于工作压力过大、个人观念偏颇、身体状况等原因引起。文章从增加抗压能力、不怨天尤人、正心等角度来分析、探讨情绪的管理。     

作业成本法在我国应用的环境分析

作业成本法(ActivityBasedCosting,ABC)是在20世纪初由美国会计学者提出的,我国于90年代开始引入,就目前的应用状况来看,还没有得到广泛的应用。本文从作业成本法概念及现实意义着手,对作业成本法的应用环境进行了深入的分析,为作业成本法在我国企业中的应用提供分析方法。     

条码管理在汽车零配件配送中心的应用

目前，我国汽车行业的信息化程度参差不齐，有些信息化程度很高．有些则刚刚处于起步状态，有些甚至仍然沿用完全手工操作记录的方式。但几乎每家企业都希望通过建立条码系统来帮助企业管理提升到一定的水平．使其整个物流环节的效率能够提高．差错率能够降低。     

An evaluation of overtime policies for a repair shop

This article presents the first attempt to develop and examine overtime policies for a repair shop environment. Overtime is used to augment repair capacity as needed to offset short-term demand fluctuations. If overtime provides sufficient additional repair capacity, it may be possible to reduce investment in spare parts inventory.The use of overtime in a repair shop requires managerial attention to several issues. In this article, the following five issues are examined: The relationship between overtime policies and spares stocking levels The timing of overtime—reactive or proactive The amount of overtime to use The level in the product structure at which overtime is most beneficial The priority scheduling and labor assignment policies usedSix overtime policies are developed that explore the above issues. These are examined using a simulation model of a hypothetical repair shop. Since the focus of the article is on overtime policies, a single labor assignment policy is used in conjunction with two priority scheduling rules.The results indicate that reactive overtime policies work well in this environment and overtime is most effective at the lowest level of the product structure, where repair times are relatively shorter. In addition, lowest level parts provide more usage flexibility to handle anticipated future failures.     

高校图书馆工作环境下网络技术的实际意义探析

文中通过介绍荆州职业技术学院图书馆自动化建设和网络化服务的情况,从图书馆的管理、服务和馆员三方面论述信息技术对高校图书馆工作的影响.