• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 추계학술대회
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• pp.223-225
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• 2021

모듈러 곱셈은 ECC의 점 스칼라 곱셈을 위한 핵심 연산이며, ECC 프로세서의 성능에 영향을 미치는 가장 중요한 요소이다. 본 논문에서는 3-way Toom-Cook 곱셈 알고리듬과 수정된 고속 축약 알고리듬을 적용한 256-비트 모듈러 곱셈기 설계에 대해 기술한다. 90-비트 곱셈기 1개와 264-비트 가산기 3개가 사용되었으며, 하드웨어 크기와 소요 클록 사이클 수 사이의 최적화를 이루었다. Zynq UltraScale+ MPSoC 디바이스에 구현하여 모듈러 곱셈기를 검증하였으며, 모듈러 곱셈 연산에 15 클록 사이클이 소요된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권7호
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• pp.3608-3628
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• 2017

Several block cipher modes of operation have been proposed in the literature to protect sensitive information. However, different security analysis models have been presented for attacking them. The analysis indicated that most of the current modes of operation are vulnerable to several attacks such as known plaintext and chosen plaintext/cipher-text attacks. Therefore, this paper proposes a secure block cipher mode of operation to thwart such attacks. In general, the proposed mode combines one-time chain keys with each plaintext before its encryption. The challenge of the proposed mode is the generation of the chain keys. The proposed mode employs the logistic map together with a nonce to dynamically generate a unique set of chain keys for every plaintext. Utilizing the logistic map assures the dynamic behavior while employing the nonce guarantees the uniqueness of the chain keys even if the same message is encrypted again. In this way, the proposed mode called SPCBC can resist the most powerful attacks including the known plaintext and chosen plaintext/cipher-text attacks. In addition, the SPCBC mode improves encryption time performance through supporting parallelized implementation. Finally, the security analysis and experimental results demonstrate that the proposed mode is robust compared to the current modes of operation.

• 전자공학회논문지B
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• 제32B권3호
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• pp.89-99
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• 1995

One of the hardest problems that limit real application of production system is its slowness. One way to overcome this problem is to speed up the matching operation which occupies more than 90% of the total execution time. In this paper, we try to speed up the matching operation with parallel execution of a typical pattern matching algorithm, RETE, in a multiprocessor environment, This requires not only to make partitions of the rules but also to allocate the partitioned rules to processors, respectively. A partition strategy is proposed to make groups of similar rules by evaluating the similarity of rules according to the number of common conditions between rules. An allocation strategy is proposed to make the load of each processor even by assigning the different priority to the group of rules according to the expected amount of time required for matching operation. To compare with the existing methods, we perform simulation using OPS5 sample programs. The simulation results show that the proposed methods can improve the performance of production system.

• 산업경영시스템학회지
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• 제39권2호
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• pp.28-36
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• 2016

Recently, owing to the development of ICT industry and wide spread of smart phone, the number of people who use car sharing service are increased rapidly. Currently two-way car sharing system with same rental and return locations are mainly operated since this system can be easily implemented and maintained. Currently the demand of one-way car sharing service has increase explosively. But this system have several obstacle in operation, especially, vehicle stock imbalance issues which invoke vehicle relocation. Hence in this study, we present an optimization approach to depot location and relocation policy in one-way car sharing systems. At first, we modelled as mixed-integer programming models whose objective is to maximize the profits of a car sharing organization considering all the revenues and costs involved and several constraints of relocation policy. And to solve this problem efficiently, we proposed a new method based on particle swarm optimization, which is one of powerful meta-heuristic method. The practical usefulness of the approach is illustrated with a case study involving satellite cities in Seoul Metrolitan Area including several candidate area where this kind systems have not been installed yet and already operating area. Our proposed approach produced plausible solutions with rapid computational time and a little deviation from optimal solution obtained by CPLEX Optimizer. Also we can find that particle swarm optimization method can be used as efficient method with various constraints. Hence based on this results, we can grasp a clear insight into the impact of depot location and relocation policy schemes on the profitability of such systems.

• 대한두개안면성형외과학회지
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• 제14권2호
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• pp.96-101
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• 2013

Background: Among facial fractures, nasal bone fracture, zygomatic arch fracture and mandibular subcondyle fracture take a large portion. Among surgical operations for nasal bone fracture, zygomatic arch fracture and mandibular subcondyle fracture, closed reduction has been generally used but, unlike open reduction, there is a problem in evaluating its accuracy of reduction. Methods: An assessment was made from October 2011 until April 2013 prospectively on 37 patients. For all the operations, closed reductions were executed in a conventional way and simultaneously using C-Arm to verify the reduction of fractures. Two images of plain radiography, one taken before operation and another one taken one day after the operation, were compared. After obtaining images of plain radiography using C-Arm immediately after the correction upon operation, they were compared with the images of plain radiography taken one day after the operation. Results: The fracture reductions of 26 patients among 27 nasal fracture patients were satisfactory but one patient showed a marginal overcorrection of less than 1 mm. The fracture reductions of 7 patients among 8 zygomatic arch fracture patients were satisfactory but one patient showed a marginal undercorrection of less than 2 mm. All of two mandibular subcondyle fracture patients showed less than 2 mm undercorrection. Conclusion: Closed reduction guided by C-Arm for nasal bone fracture, zygomatic arch fracture and mandibular subcondyle fracture was clinically useful because it could make a real-time assessment on fractured areas and add immediate corrections during the operation.

• 대한산업공학회지
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• 제21권3호
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• pp.329-343
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• 1995

Traditionally, machining process sequence was influenced and constrained by the design information obtained from CAD data base, i.e., class of operations, geometric shape, tooling, geometric tolerance, etc. However, even though all the constraints from design information are considered, there may exist more than one way to feasibly machine parts. This research is focused on the integrated problem of operations sequencing and machine tools selection in the presence of the product mix and their production volumes. With the transitional costs among machining operations, the operation sequencing problem can be formulated as a well-known Traveling Salesman Problem (TSP). The transitional cost between two operations is expressed as the sum of total machining time of the parts on a machine for the first operation and transportation time of the parts from the first machine to a machine for the second operation. Therefore, the operation sequencing problem formulated as TSP cannot be solved without transitional costs for all operation pairs. When solved separately or serially, their mutual optima cannot be guaranteed. Machining operations sequencing and machine tool selection problems are two core problems in process planning for discretely machined parts. In this paper, the interrelated two problems are integrated and analyzed, zero-one integer programming model for the integrated problem is formulated, and the solution methods are developed using a Tabu Search technique.

• 항공우주시스템공학회지
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• 제14권6호
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• pp.26-35
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• 2020

The national satellite operation network, which supports multiple satellites, was designated as a Critical Information Infrastructure (CII) in 2017. The network was designed independently from the control network and the information network to enhance physical security. Planning is underway to establish a bidirectional data interface between networks. The data transmission system allows data flow only to the physical layer and the data link layer; hence, only one file can be transferred at any one time. This means that when large amounts of data are being transmitted, no other data can be sent simultaneously in urgent situations. Thus, this paper discusses the design of flexible packets for the transmission of data between networks in an environment where physical security has been enhanced through network separation and based on this, presents a method for transmitting data effectively.

• 한국공작기계학회논문집
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• 제17권5호
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• pp.70-75
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• 2008

This paper describes a tool-clamping/unclamping mechanism for application of a micro-spindle. The mechanism is based on one-way shape memory effect and interference-fit. The corresponding mathematical models and a few considerable design parameters are mentioned in this paper. Especially, necessary conditions for the clamping and unclamping operation are investigated through finite element analysis. The analysis results show that the differences between the diametral deformations of the tool holder in high temperature and that in low temperature are increased according to amounts of the interference. Thus the less interference between the tool-holder and the ring, the less tolerance to allow the clamping and unclamping operation because the inner diameter of the tool holder in high temperature should be smaller than the diameter of the tool shank, and that in low temperature should be larger than the diameter of the tool shank. In addition, the design for maximization of clamping force are investigated based on finite element analysis. The results show that the more amounts of the interference, the more clamping force. As the result, the interference should be considered as a important factor to maximize the tool clamping force.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.562-569
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• 2004

To operate a border station between South and North Korea is one of the most important tasks for the future inter-Korean railway transportation. Currently, North Korea and China are operating three border stations each. Among them, a Dandong-Sinuiju route handles the most amount of transport volume and can be a model for the operation of South-North Korean border station. This Study is to suggest an efficient way of operating the planned South-North Korean border station and international railway transportation via the station. To that end, operation system at the border station between Chinese Dandong and North Korean Sinuiju was analyzed and the Train Operation Agreement made by the two Koreas was studied.

• 농촌지도와개발
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• 제7권2호
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• pp.289-293
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• 2000

The way society works in the 21st century differs from that of 20th century, since the people are brought-up to speed regarding current technologies. The www.aflos.pe.kr site and direct e-mailing system were very useful in delivering floricultural information to extension educators, producers, and variety of individuals. The author’s one year experience indicated that extension educators and farmers are receptive to internet technologies, and extension educators have increased the knowledge base of their clientele by responding through direct e-mails. The internet and direct e-mailing systems were popular and powerful way of transferring floricultural information, especially agricultural extension manpower were limited because of localization of extension educators by changing national status to local governments and decreased number of extension educators through government restructuring. The direct e-mailing to approximately 503 individuals resulted about $1{\sim}3%$ responses and the number of phone calls, however virus protection software for e-mail, internet, file servers and desktops to provide the integrated real-time detection of viruses were needed. For more effective operation of direct e-mailing in the future, more specified target groups and specialized organization such as perennials, bulbs, flowering potted plants. and cut flowers. At the same time, things that have worked for last century should not be replaced with new technology, specifically, the value in one-on-one meetings should not be replaced, but rather serve as a supplement.