• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05b
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• pp.127-129
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• 2005

We investigated the fault current limiting characteristics according to the various facilities in power system. Power systems are becoming larger and larger for meeting electric power demand. Therefore, the over-currents resulting from contingencies such as short circuits are increasing higher, which causes the ratings of circuit breakers(CBs) to increase. Upgrading or replacement of CBs is not difficult from the technical and economical point of view. Bus split is being adopted into a part of 154 kV power systems, but it has adverse effects such as overload to neighboring power systems, increased voltage fluctuation, and decreased power system stability. For 345 kV power systems, the bus split measure is not feasible and dc reactors are being suggested. The superconducting fault current limiter is a protection gear of new concept that limits fault current automatically in a few milliseconds. It can also provide the effect of CB capacity increase, relaxation of power machine criteria, enhancement in power system reliability, and flexible power system operation.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.3-9
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• 2008

Recently, the plant industries are being activated and plant control systems use various technologies. Because the optimized design for the plants is very important for the reducing of operation and maintenance costs, automatic control systems become more important. Plant control systems consist of the master controller, the plant networks, the programming environment for engineering, monitoring software and the field devices. The control systems should have reliability, availability and safety. Modular architecture of hardware and software makes flexible configuration of the control systems. Each component should have diagnostic functions. It follows industrial standards and makes open systems. Open systems increase accessibility against the data which is distributed in the plants. The controllers including processor and communication modules use the up-to-date technology. They have real time and fault tolerant function by duplicating processors or networks. It also enables to make the distributed control systems. The distributed architecture makes more scalable main control system. Automatic control systems can be operated with better performance. In this paper, we analyzed the requirements of the seawater desalination plants and made some consideration facts for developing the optimized controller. Also we described the design concept of the main controller, which consists of several modules. We should validate and complement the design for the reliability and better performance.

• International Journal of High-Rise Buildings
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• v.9 no.1
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• pp.95-104
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• 2020

Recently, robotic technologies have significantly improved, bringing considerable enhancements in many sectors; the main objective of this paper is to figure out if these innovations have also involved the building industry. To achieve this purpose, it has been considered crucial to first reshape and clarify some concepts, incorporating a much more flexible understanding of the term "robot", as well as the formulation of its future potential. Subsequently, it has been carried out an analysis of the various advanced devices that are currently available to be employed in the construction processes; the review includes a thorough classification of construction robots, divided into 18 families reflecting their purpose of use, and a dissection based on the term used to define them. The attention has been focused on the most updated and recent robots and, in their absence, on the most advanced machines prevailing. This operation has been achieved taking into account the development history of construction robots, as well as the analyses and classifications previously conducted, reconsidering them according to the just mentioned reflections. Furthermore, an in-depth exploration of the exoskeletons, as well as on a sophisticated robot recently developed by Schindler Group has been executed.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2001.05a
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• pp.1-10
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• 2001

SNMPv3 provides the security services such as authentication and privacy of messages as well as a new flexible and extensible administration framework. Therefore, with the security services enabled by SNMPv3, network managers can monitor and control the operation of network components more secure way than before. But, due to the user-centric security management and the deficiency of policy-based security management facility, SNMPv3 might be inadequate network management solution for large-scaled networks. In this paper, we review the problems of the SNMPv3 security services, and propose a Role-based Security Management Model(RSM), which greatly reduces the complexity of permission management by specifying and enforcing a security management policy far entire network.

• Journal of Fisheries and Marine Sciences Education
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• v.19 no.2
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• pp.278-287
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• 2007

Since traffic congestion ratio at any given port fluctuates on the number of arriving and departing vessels, the total tonnage of freight volume being handled, and the number of berth in operation and other factors, there exists a need to numerically analyze the waterway traffic volume. However, there are no effective regulations in regards to the waterway traffic analysis prior to expansion of a port facility. The current analysis requires the traffic analysis in relation only to the width of the waterway, which clearly falls short of achieving a comprehensive evaluation study that could be used in consideration of port expansion.This study provides five scenarios to execute a comprehensive evaluation study and base for the sensitivity study by analyzing the scenarios. As a result of the sensitivity analysis, the A, B, and C scenarios varies the average arrival ratio of the berth shows 1.1, 1.19, and 1.28 times of delays respectively. Also, The D and E scenarios take place malfunctions of pier shows 1.21 and 1.53 times of delays respectively. Therefore, various strategies of harbor development and method of harbor management are needed for the flexible correspondence to the environmental changes such as the excessive increasing of the freight volume and often taking place of malfunctioning.

• ETRI Journal
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• v.19 no.3
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• pp.186-201
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• 1997

In this paper, a home location register (HLR) for CDMA mobile communication system (CMS) is introduced. It stores the mobile station (MS) subscribers locations and supplementary service information. Call processing procedures for HLR are developed to receive and store subscriber's location coming from mobile exchange (MX) during the location registration, and to transfer subscriber's location and supplementary service information to the MX during the mobile-terminated call setup. For fast call processing by increasing database access speed, a memory-resident database management system is devised. For Easy and secure HLR operation, administration and maintenance functions and overload control mechanisms are implemented. Designed HLR hardware platform is expandable and flexible enough to reallocated software blocks to any subsystems within the platform. It is configurable according to the size of subscribers. An authentication center (AC) is developed on the same platform. It screens the qualified MS from the unqualified. The calls to and from the unqualified MS are rejected in CMS. To authenticate the MS, the AC generates a new authentication parameter called "AUTHR" using shared secret data (SSD) and compared it with the other AUTHR received from the MS. The MC also generates and stores seed keys called "A-keys" which are used to generate SSDs. The HLR requirements, the AC requirements, software architecture, hardware platform, and test results are discussed.

• ETRI Journal
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• v.31 no.6
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• pp.717-724
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• 2009

This paper describes a 1.2 V 12 b 60 MS/s CMOS analog front-end (AFE) employing low-power and flexible design techniques for image signal processing. An op-amp preset technique and programmable capacitor array scheme are used in a variable gain amplifier to reduce the power consumption with a small area of the AFE. A pipelined analog-to-digital converter with variable resolution and a clock detector provide operation flexibility with regard to resolution and speed. The AFE is fabricated in a 0.13 ${\mu}m$ CMOS process and shows a gain error of 0.68 LSB with 0.0352 dB gain steps and a differential/integral nonlinearity of 0.64/1.58 LSB. The signal-to-noise ratio of the AFE is 59.7 dB at a 60 MHz sampling frequency. The AFE occupies 1.73 $mm^2$ and dissipates 64 mW from a 1.2 V supply. Also, the performance of the proposed AFE is demonstrated by an implementation of an image signal processing platform for digital camcorders.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.8
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• pp.709-714
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• 2001

Recently, most vehicles has the Automatic transmission system as their transmission system. The automatic transmission system operates with fixed shift patterns. In the opposite of manual operation, it is easy and convenient for driving. Though these merit, the system can not evaluate the driver s intension because of usage of fixed shift pattern. To consider driver s intension, we must consider both the driving intensity of driver and the status of vehicle. In this paper, we developed flexible automatic transmission system by using the proposed moduled neural networks which can learn the status of th vehicle and driver s intensity. As a results, we compare the transmission system using fixed shift pattern and the proposed transmission system and show the good performance in the change of shift position.

• Journal of the Korean housing association
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• v.9 no.2
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• pp.33-41
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• 1998

To accomodate increasing housing shortage in many cities, Korean Government has implemented various residental land development projects to provide more land for new housing construction. Most of the residential areas developed by these projects were used for multi-family housing units. Under this process, the size and location of the neighborhood service facilities in the development area were regulated by uniform standards. For this reason, the neighborhood service facilities were not able to be provided according to the household density but provided in minimum status required by these standards. Based on these considerations, this study aimed to evaluated residential land development project conducted by pubilc authority, one of the residential land development projects in Korea. Results of the case studies confirmed findings from literature review and proposed that existing regulations applied to these projects need to be amended not only to accomodata unique situation of each development area but also to enhance level of the dwelling environment. As ways to resolve these problems, this study suggests followings: (1) more flexible operation of the regulations, (2) inclusion of the socio-economic characteristics of the perspective resident in planning process, and (3) introduction of design techniques in the project. Finally, this study proposed future study directions in relation to this issue.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.323-324
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• 2013

This paper presents a simple and cost-effective stand-alone rapid battery charging system of 30kW for electric vehicles. The proposed system mainly consists of active front-end rectifier of neutral point clamped 3-level type and non-isolated bi-directional dc-dc converter of multi-phase interleaved half-bridge topology. The charging system is designed to operate for both lithium-polymer and lithium-ion batteries. The complete charging sequence is made up of three sub-interval operating modes; pre-charge mode, constant-current mode, and constant-voltage mode. The pre-charge mode employs the stair-case shaped current profile to accomplish shorter charging time while maintaining the reliable operation of the battery. The proposed system is specified to reach the full-charge state within less than 16min for the battery capacity of 8kWh by supplying the charging current of 78A. Owing to the simple and compact power conversion scheme, the proposed solution has superior module-friendly mechanical structure which is absolutely required to realize flexible power expansion capability in a very high-current rapid charging system.