• Journal of information and communication convergence engineering
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• v.14 no.2
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• pp.122-128
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• 2016

In the future, hybrid power management systems using fuel cells (FCs) and batteries will be used as the driving power systems of ships. These systems consist of an FC, a converter, an inverter, and a battery. In general, an FC provides steady-state energy; a battery provides the dynamic energy in the start state of a ship for enabling a smooth operation, and provides or absorbs the peak or dynamic power when the load varies and the FC cannot respond immediately. The FC voltage range is very wide and depends on the load; Therefore, the FC cannot directly connect to the inverter. In this paper, we propose a power management strategy and design process involving a unidirectional converter, a bidirectional converter, and an inverter, considering the ship's operating conditions and the power conditions of the FC and the battery. The presented experimental results were verified through a simulation.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.11a
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• pp.211-214
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• 2003

Recently mobile SFA(Sales Force Automation) system makes rapidly progress specially in industries like insurance, manufacture, and distribution. However, there are some problems that information about products and trades is not promptly shared among sales agents or customers, since the current mobile SFA system has simply extended the existing systems for sales management. In order to improve these weaknesses, we introduce LBS(Location Based Service) and mobile P2P(Peer to Peer) service into the existing systems, then design and implement the enhanced system (or mobile SFA using them. Through this improvement, our system makes it possible for customers or sales agents to quickly share various information and increases the efficiency of sales activity by facilitating the competition and cooperation among sales agents and reducing time-cost.

• Journal of Korean Institute of Industrial Engineers
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• v.27 no.1
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• pp.37-46
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• 2001

Business process(workflow) analysis has been recognized as a core step to building information systems. However, most analysts have recognized that deriving consistent business process artifacts even in a simple business domain is very difficult, since most analysis methods give the designers narrative and/or diagrammatic tools that do not support rigorous analysis rules. This often generates inconsistent analysis results, leading to create useless information systems and resulting in tremendous budget wastes. To overcome this weakness, this paper presents a declarative business process modeling method called contract-collaboration net(cc-net), which is not only somewhat formal but also useful to the practitioners. A case study on bank domain is presented to illustrate our approach.

• Korean Management Science Review
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• v.12 no.1
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• pp.79-94
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• 1995

Nowadays, a large number of Executive Information Systems (EIS) have been developed around the world, most of them are in the United States. These systems were mainly for senior executives to monitor the current status and to find out possible opportunities/problems of their organizations. They also provide a number of capabilities such as drill-down, exception reporting, and trend analysis on hard and soft data from both internal and external sources. The purpose of this study is to see where the current status of the use of EIS in Korea and the Korean EIS industry are. The survey result is valuable to Korean EIS developers - both in-house developers and outside vendors. They can develop appropriate EISs based on the findings.

• Smart Structures and Systems
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• v.25 no.4
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• pp.401-408
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• 2020

This paper deals with the problem of global stabilization for a class of nonlinear control systems. An effective approach is proposed for controlling the system interaction of structures through a combination of parallel distributed compensation (PDC) intelligent controllers and fuzzy observers. An efficient approximate inference algorithm using expectation propagation and a Bayesian additive model is developed which allows us to predict the total number of control systems, thereby contributing to a more adaptive trajectory for the closed-loop system and that of its corresponding model. The closed-loop fuzzy system can be made as close as desired, so that the behavior of the closed-loop system can be rigorously predicted by establishing that of the closed-loop fuzzy system.

• Journal of information and communication convergence engineering
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• v.15 no.1
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• pp.21-27
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• 2017

In this research, we study the outage probability for distributed space-time coding-based cooperative (DSTC) systems with amplify-and-forward relaying over Rayleigh fading channels with a high temporal correlation where the direct link between the source and the destination is available. In particular, we derive the upper and lower bounds of the outage probability as well as their corresponding asymptotic expressions. In addition, using only the average channel powers for the source-to-relay and relay-to-destination links, we propose an efficient power allocation scheme between the source and the relay to minimize the asymptotic upper bound of the outage probability. Through a numerical investigation, we verify the analytical expressions as well as the effectiveness of the proposed efficient power allocation. The numerical results show that the lower and upper bounds tightly correspond to the exact outage probability, and the proposed efficient power allocation scheme provides an outage probability similar to that of the optimal power allocation scheme that minimizes the exact outage probability.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.48
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• pp.101-111
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• 1998

CNS (Car Navigation System) is the most compatible candidate among various in-vehicle information systems as a provider of ITS (Intelligence Transport Systems) information. It generally consists of remote controller, display, CD-changer, GPS receiver and so on. Among them, display is the most important and critical element of the HMI (Human-Machine Interface) suggesting the digital map to the driver. Therefore, it is certain that the display gives cognitive, physical, mental and visual workloads to the driver which are directly related with the driver's and road safety with the success of ITS. Until now, various human factors techniques have been developed and applied to estimate the driver's workload and to collect the driver's requirements of the CNS digital map, for example, mental workload assessment, visual activity analysis, cognitive analysis and so on. In addition to these kinds of techniques, this research performed the human sensibility ergonomics approach to directly investigate and evaluate the driver's requirements and sensibilities of the real products.

• ETRI Journal
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• v.34 no.1
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• pp.55-65
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• 2012

E-voting is expected to offer prominent advantages over traditional voting methods. Advantages include faster tallying, greater accuracy, prevention of void ballots, and lower cost. However, many experts express concerns about the potential for large-scale fraud. Recently, many paper based end-to-end (E2E) voter verifiable systems providing individual verifiability and universal verifiability have been proposed. These systems, unlike previous voting systems, are used in polling booths and without access to trusted computing devices at the time of voting. In this paper, we propose a practical and secure E2E voter verifiable system using a paper receipt based on cryptographic technologies.

• The Journal of Information Technology
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• v.4 no.3
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• pp.65-75
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• 2001

Code-division multiple access has been widely accepted as the major multiple access scheme in mobile communication systems. Wide-band CDMA and its hybrid associate time-division CDMA are key elements in the mobile communication. Since 10 years ago, there has been enormous research activity in analysis of the capacity of these CDMA-based systems. Recently, upgrading service, high quality and the different service classes in radio resource allocation has recently increased. This paper presents an overview of Radio Resource Allocation on the CDMA-based systems that are flexible, support traffic services, minimize call blocking rate and have acceptable radio resource utilization.

• Asia pacific journal of information systems
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• v.12 no.2
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• pp.25-44
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• 2002

The internet-based electronic commerce is considered as a new strategic alternative to boost competitiveness for small and medium-sized enterprises(SMEs). However, very little research about them has been reported. Meanwhile, the cyber shopping shops in Korea are growing rapidly in their numbers, scales, and diversity of business models. The primary purpose of this study is to investigate the factors influencing outsourcing decisions in the implementation of small and medium-sized cyber shopping shops. Based on the previous studies on IS outsourcing, marketing channel, and their related theories, three areas of determinants(IT & organizational, product, marketing channel characteristics) were identified. Responses of 125 cyber shopping shops from e-mail survey indicate that IT capability, technical specificity of shop implementation, degree of product customization, average amount of order, marketing capability are negatively associated with outsourcing of cyber shopping shop implementation. The results also indicate that the outsourcing decision on systems implementation and marketing channel selection(direct/indirect selling) is performed separately.