• Journal of Applied Reliability
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• v.7 no.2
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• pp.73-87
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• 2007

In this paper, based on the American weapon acquisition management framework in DoD Instruction 5000.2 "Operation of the Defence Acquisition System" and the contents of "DoD Guide for Achieving Reliability, Availability, and Maintainability" published by Defense Acquisition University, the kinds and roles of technical reviews are introduced and the identification of RAM related tasks which are performed at levels of technical reviews during acquisition process are considered. And the task allocations for developers, development managers, and users are proposed. Finally the relationships of acquisition management framework, technical reviews and RAM tasks are tabulated.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.7
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• pp.3413-3430
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• 2017

With the fast increasing popularity of mobile services, ubiquitous mobile devices with enhanced sensing capabilities collect and share local information towards a common goal. The recent Mobile Crowd Sensing (MCS) paradigm enables a broad range of mobile applications and undoubtedly revolutionizes many sectors of our life. A critical challenge for the MCS paradigm is to induce mobile devices to be workers providing sensing services. In this study, we examine the problem of sensing task assignment to maximize the overall performance in MCS system while ensuring reciprocal advantages among mobile devices. Based on the overlapping coalition game model, we propose a novel workload determination scheme for each individual device. The proposed scheme can effectively decompose the complex optimization problem and obtains an effective solution using the interactive learning process. Finally, we have conducted extensive simulations, and the results demonstrate that the proposed scheme achieves a fair tradeoff solution between the MCS performance and the profit of individual devices.

• Journal of the Korean Society of Safety
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• v.15 no.1
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• pp.167-175
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• 2000

Work performance and human error are complicated phenomena so that it is very difficult to grasp the true nature of them. However, Event Related Potential (ERP) may give a clue to them because human brain reflects diverse psychophysiological process. In the present study, the possibility of ERP application to the ergonomic area was evaluated in view of grasping error symptoms. For that purpose, the subjects were asked to count specific characters in a random character matrix on a computer monitor, and their ERP was compared with their performance data. Based upon the results, the amplitude of P300 was not so high as that in the case of the Odd Ball tasks, correct response corresponded with stable ERP with high P300 amplitude whereas wrong response did with unstable, fluctuating ERP with low P300 amplitude. Those results coincided with the work performance, and it was concluded that 3-wave fluorescent with illumination level of 800 lux would be recommendable for the counting task in concern. Conclusively, ERP including P300 might supply an objective clue to the problem of human errors in cognitive process.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.314-317
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• 2000

Cluster system provides attractive scalability in terms of computation power and memory size. With the advances in high speed computer network technology, cluster systems are becoming increasingly competitive compared to expensive parallel machines. In parallel processing program, each task load is difficult to predict before running the program and each task is interdependent each other in many ways. Load imbalancing induces an obstacle to system performance. Most of researches in load balancing were concerned with distributed system but researches in cluster system are few. In cluster system, the dynamic load balancing algorithm which evaluates each processor's load in runtime is purpose that the load of each node are evenly distributed. But, if communication cost or node complexity becomes high, it is not effective method for all nodes to attend load balancing process. In that circumstances, it is good to reduce the number of node which attend to load balancing process. We have modeled cluster systems and proposed marginal dynamic load balancing algorithms suitable for that circumstances.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.4
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• pp.27-36
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• 1993

This paper proposes a shortest path allocation algorithm over the processors on the hypercube system based on the message passing techniques with the optimized module allocation. On multiprocessor systems, how to divide one task into multiple tasks efficiently is an important issue due to the hardness of the life cycle estimation of each process. To solve the life cycle discrepancies, the appropriate task assignment to each processor and the flexible communications among the processors are indispensible. With the concurrent program execution on hypercube systems, each process communicaties to others with the method of message passing. And, each processor has its own memory. The proposed algorithm generates a callable tree out of the module, assigns the weight factors, constructs the allocation graph, finds the shortest path allocation tree, and maps them with hypercube.

• Journal of the Ergonomics Society of Korea
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• v.32 no.3
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• pp.259-266
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• 2013

Objective: This study aims to evaluate the workloads of industrial and automobile storage battery industries and their association to biological exposure indices. Background: Occupational lead exposure at battery manufacturing workplace is the most serious problem in safety and health management. Method: We surveyed 145 workers in 3 storage battery industries. Environmental factors(lead in air, temperature, humidity and vibration)), biological exposure indices(lead in blood and zinc protoporphyrin in blood) and individual workload factors(process type, work time, task type, weight handling and restrictive clothing) were measured in each unit workplace. Results/Conclusion: Air lead concentration is statistically significant in associations with workload factors(process type, work time, task type, and restrictive clothing) and environmental factors (humidity and vibration), whereas zinc protoporphyrin in blood are significantly associated with work time and weight handling. And lead in blood is significantly associated with work time, weight handling and temperature. Application: The results of this study are expected to be a fundamental data to job design.

• Journal of Intelligence and Information Systems
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• v.18 no.2
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• pp.157-175
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• 2012

It is difficult to evaluate the performance of process innovation of e-procurement which has large scale and complex processes. The existing evaluation methods for measuring the effects of process innovation have been mainly done with statistically quantitative methods by analyzing operational data or with qualitative methods by conducting surveys and interviews. However, these methods have some limitations to evaluate the effects because the performance evaluation of e-procurement process innovation should consider the interactions among participants who are active either directly or indirectly through the processes. This study considers the e-procurement process as a complex system and develops a simulation model based on MAS(Multi-Agent System) to evaluate the effects of e-procurement process innovation. Multi-agent based simulation allows observing interaction patterns of objects in virtual world through relationship among objects and their behavioral mechanism. Agent-based simulation is suitable especially for complex business problems. In this study, we used Netlogo Version 4.1.3 as a MAS simulation tool which was developed in Northwestern University. To do this, we developed a interaction model of agents in MAS environment. We defined process agents and task agents, and assigned their behavioral characteristics. The developed simulation model was applied to G2B system (KONEPS: Korea ON-line E-Procurement System) of Public Procurement Service (PPS) in Korea and used to evaluate the innovation effects of the G2B system. KONEPS is a successfully established e-procurement system started in the year 2002. KONEPS is a representative e-Procurement system which integrates characteristics of e-commerce into government for business procurement activities. KONEPS deserves the international recognition considering the annual transaction volume of 56 billion dollars, daily exchanges of electronic documents, users consisted of 121,000 suppliers and 37,000 public organizations, and the 4.5 billion dollars of cost saving. For the simulation, we analyzed the e-procurement of process of KONEPS into eight sub processes such as 'process 1: search products and acquisition of proposal', 'process 2 : review the methods of contracts and item features', 'process 3 : a notice of bid', 'process 4 : registration and confirmation of qualification', 'process 5 : bidding', 'process 6 : a screening test', 'process 7 : contracts', and 'process 8 : invoice and payment'. For the parameter settings of the agents behavior, we collected some data from the transactional database of PPS and some information by conducting a survey. The used data for the simulation are 'participants (government organizations, local government organizations and public institutions)', 'the number of bidding per year', 'the number of total contracts', 'the number of shopping mall transactions', 'the rate of contracts between bidding and shopping mall', 'the successful bidding ratio', and the estimated time for each process. The comparison was done for the difference of time consumption between 'before the innovation (As-was)' and 'after the innovation (As-is).' The results showed that there were productivity improvements in every eight sub processes. The decrease ratio of 'average number of task processing' was 92.7% and the decrease ratio of 'average time of task processing' was 95.4% in entire processes when we use G2B system comparing to the conventional method. Also, this study found that the process innovation effect will be enhanced if the task process related to the 'contract' can be improved. This study shows the usability and possibility of using MAS in process innovation evaluation and its modeling.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.112-118
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• 2005

Workflow is a collection of tasks organized to accomplish some business processes. It also defines the order of task invocation or conditions under which task must be invoked, task synchronization, and information flow. And activity based costing(ABC) provides accurate cost information for decision making. In ABC systems, costs must be separable into cost pools each of which corresponding to a single cost driver. These two systems are closely related to each other. But recent research deals with workflows and ABC systems separately. Thus, this research proposes an extended workflow model which is expressed cost information using activity based costing.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.51-55
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• 2001

With the rapid growth of the World Wide Web and electronic information services, information is becoming available on-Line at an incredible rate. One result is the oft-decried information overload. No one has time to read everything, yet we often have to make critical decisions based on what we are able to assimilate. The technology of automatic text summarization is becoming indispensable for dealing with this problem. Text summarization is the process of distilling the most important information from a source to produce an abridged version for a particular user or task. Information retrieval(IR) is the task of searching a set of documents for some query-relevant documents. On the other hand, text summarization is considered to be the task of searching a document, a set of sentences, for some topic-relevant sentences. In this paper, we show that document information, that is more reliable and suitable for query, using document length normalization of which is gained through information retrieval . Experimental results of this system in newspaper articles show that document length normalization method superior to other methods use query itself.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2489-2491
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• 2005

Currently, Programmable Logic Contorller(PLC) uses Real Time Operation System(RTOS) as basic OS. RTOS executes defined results as to defined time. General features of RTOS emphasize the priority in each task, high-speed process of external interrupt, task scheduling, synchronization in task, the limitation of memory capacity. For safety critical placement, PLC software needs Verification and Validation(V&V). For example, nuclear power plant. In this paper, PLC RTOS is verified by formal methods. Particularly, formal method V&V uses verification tool called 'STATEMATE', and shows the results.