• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권11호
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• pp.5717-5730
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• 2019

LBlock-s is the core block cipher of authentication encryption algorithm LAC, which uses the same structure of LBlock and an improved key schedule algorithm with better diffusion property. Using the differential properties of the key schedule algorithm and the cryptanalytic technique which combines impossible boomerang attacks with related-key attacks, a 15-round related-key impossible boomerang distinguisher is constructed for the first time. Based on the distinguisher, an attack on 22-round LBlock-s is proposed by adding 4 rounds on the top and 3 rounds at the bottom. The time complexity is about only 2^68.76 22-round encryptions and the data complexity is about 2⁵⁸ chosen plaintexts. Compared with published cryptanalysis results on LBlock-s, there has been a sharp decrease in time complexity and an ideal data complexity.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 추계학술대회
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• pp.263-266
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• 2012

본 논문에서는 ISO/IEC 10118-3의 표준인 Whirlpool 해쉬 함수의 효율적인 하드웨어 설계와 FPGA 검증에 대해 기술한다. Pipelined small LUT를 이용하여 동작 타이밍을 최적화하였으며, Whirlpool 블록암호와 key schedule을 병렬로 사용하여 throughput을 개선하였다. 키 스케쥴에서 키 덧셈부분에 rom과 xor 게이트를 사용하지 않고 인버터와 mux로 구현하여 면적을 최적화하였다. Virtex5-XC5VSX50T를 사용하여 FPGA 검증을 하였고 최대 동작 주파수는 약 151MHz이며, 약 950Mbps의 성능을 가진다.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.527-531
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• 2015

With the mounting concerns over environmental issues, green construction is gaining a place in the global construction industry. However, rare research has been conducted to analyze green construction projects, especially in the aspect of project schedule performance. As a result, this study aims to investigate the degree of project delay in green building construction, analyze the factors affecting schedule delay of green building projects, and finally provide recommendations to improve schedule performance of green building project. To achieve the objectives, a comprehensive literature review was carried out, followed by a survey conducted with 30 companies that provided data from 220 traditional and 96 green building projects. The analysis of the responses identified that 15.9% of the traditional building projects were delayed while 32.3% of the green building projects were completed behind schedule. Furthermore, the amount of the delays in green building projects was an average of 4.8% of their planned schedule. The top 5 critical factors that can cause delay in green building projects were identified as: (1) speed of decision-making by clients; (2) speed of decision-making involving all project teams; (3) communication/coordination between key parties; (4) level of experience of consultants; and (5) difficulties in contractors' project financing. Lastly, a list of recommendations was introduced, aiming to reduce schedule delay in green building construction projects based on the observations. This study will serve as s a base for further research on the enhancement of green building project schedule performance.

• 산업경영시스템학회지
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• 제42권1호
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• pp.64-73
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• 2019

The manufacturing companies under Make-To-Order (MTO) production environment face highly variable requirements of the customers. It makes them difficult to establish preemptive production strategy through inventory management and demand forecasting. Therefore, the ability to establish an optimal production schedule that incorporates the various requirements of the customers is emphasized as the key success factor. In this study, we suggest a process of designing the simulation model for establishing production schedule and apply this model to the case of a flat glass processing company. The flat glass manufacturing industry is under MTO production environment. Academic research of flat glass industry is focused on minimizing the waste in the cutting process. In addition, in the practical view, the flat glass manufacturing companies tend to establish the production schedule based on the intuition of production manager and it results in failure of meeting the due date. Based on these findings, the case study aims to present the process of drawing up a production schedule through simulation modeling. The actual data of Korean flat glass processing company were used to make a monthly production schedule. To do this, five scenarios based on dispatching rules are considered and each scenario is evaluated by three key performance indicators for delivery compliance. We used B2MML (Business To Manufacturing Markup Language) schema for integrating manufacturing systems and simulations are carried out by using SIMIO simulation software. The results provide the basis for determining a suitable production schedule from the production manager's perspective.

• 한국항행학회논문지
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• 제15권1호
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• pp.69-75
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• 2011

본 논문에서는 블록암호 SEED-192 키 스케줄 취약점을 분석한다. 본 연구 결과에 의하면, SEED-192는 전체 20 라운드 중 16 라운드에 대해, 연관키 렉탱글/부메랑 공격에 대한 취약키가 존재한다. 이는 SEED-192 키 스케줄에 대한 최초의 분석 결과이다.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.213-216
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• 1996

R'||'&'||'D project management is a process of decisions concerned with the achievement of goals of objectives. Especially, defense R'||'&'||'D project planning is the key in the successfull management of defense development. The defense project managers are constantly having to perform "what if\ulcorner" exercise, such as what if the project is extended out for an additional cost\ulcorner In this reserch, we developed a schedule-cost analysis model based upon Critical Path Method(CPM) and Venture Evaluation and Review Technique(VERT) for schedule-cost trade off analysis defense R'||'&'||'D projects. In the first step, a deterministic model is developed as a heuristic which deterministic model is developed as a heuristic which determines the schedule extension and reduction cost as a function desired schedule. In the second step, a stochastic network simulation model is developed to analyse the project risk (sucess and failure). The expected time and cost can be determined for desired schedule under the assumptions of stochastic arc data (time and cost) with a various precedence relationships. This model provides the defense R'||'&'||'D managers with an estimated and expected cost for curtailing or extending a project a given amount of time. The effectiveness and efficiency of the proposed methods, a heuristic and stochastic networks simulations, have been demonstrated through examples.

• Journal of Information Processing Systems
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• 제7권4호
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• pp.613-626
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• 2011

In this paper, we focus on the pinwheel task model with a variable voltage processor with d discrete voltage/speed levels. We propose an intra-task DVS algorithm, which constructs a minimum energy schedule for k tasks in O(d+k log k) time We also give an inter-task DVS algorithm with O(d+n log n) time, where n denotes the number of jobs. Previous approaches solve this problem by generating a canonical schedule beforehand and adjusting the tasks' speed in O(dn log n) or O($n^3$) time. However, the length of a canonical schedule depends on the hyper period of those task periods and is of exponential length in general. In our approach, the tasks with arbitrary periods are first transformed into harmonic periods and then profile their key features. Afterward, an optimal discrete voltage schedule can be computed directly from those features.

• 디지털콘텐츠학회 논문지
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• 제16권4호
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• pp.555-564
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• 2015

최근 건설 프로젝트가 대형화, 복잡화, 전문화되면서 다양한 참여자들 사이에서 발생하는 방대한 양의 정보 활용이 중요해 지고 있다. 발생되는 다양한 정보 중 일정정보는 건설프로젝트의 중심적인 정보이다. 건설현장 관련 참여자간 일정정보교환 미흡은 공기지연, 품질하자와 같은 건설생산성 저해 요인을 유발한다. 현재, 건설 산업에서는 건축물의 전 생애 주기 동안 필요한 데이터를 생산하고 관리하는 BIM(Building Information Modeling)에 대한 관심이 높아지고 있다. 본 연구는 BIM을 기반으로 건설공사의 일정정보를 체계적으로 관리 할 수 있는 일정관리 정보 체계를 구축하는 것이다. 이를 위해 BIM적용 일정관리 업무 프로세스를 구축하였으며, 일정정보를 구축하기 위한 작업분류체계를 도출 하였다. 또한 일정정보 구축에 필요한 속성 중 BIM모델에서 추출 할 수 있는 정보를 도출하고, 일정관리에 필요한 속성정보와 연계하여 일정을 생성 하고 공사 진행 시점별 일정관리를 위한 필요 정보를 제시한다.

• Journal of information and communication convergence engineering
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• 제3권4호
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• pp.201-204
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• 2005

Twofish is a 128-bit block cipher that accepts a variable-length key up to 256 bits. The cipher is a 16­round Feistel network with a bijective F function made up of four key-dependent 8-by-8-bit S-boxes, a fixed 4­by-4 maximum distance separable matrix over Galois Field$(GF (2^8)$, a pseudo-Hadamard transform, bitwise rotations, and a carefully designed key schedule. In this paper, the Twofish is modeled in VHDL and simulated. Hardware implementation gives much better performance than software-based approaches.

• 정보보호학회논문지
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• 제18권3호
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• pp.69-77
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• 2008

전력분석 공격이 소개되면서 다양한 대응법들이 제안되었고 그러한 대응법들 중 블록 암호의 경우, 암/복호화, 키 스케쥴링의 연산 도중 중간 값이 전력 측정에 의해 드러나지 않도록 하는 마스킹 기법이 잘 알려져 있다. 마스킹 기법은 블록 암호의 구성에 따라 적용 방법이 달라질 수 있으며, 각각의 블록암호에 적합한 마스킹 기법에 대한 연구가 진행되고 있다. ARIA의 경우, 기존 마스킹 방법들은 마스킹 보정작업으로 인해 암호 연산시간이 상당히 길며 키스케쥴링 공격이 다른 블록 암호들보다. ARIA에 더 위협적임에도 불구하고 키스케쥴링 과정에 마스킹 방법을 고려하지 않는다. 본 논문에서는 키 스케쥴링 과정을 포함한 ARIA에 적합한 효율적인 마스킹 기법을 제안한다. 제안하는 방법은 기존 방법들보다 암호 연산 시간을 단축시키고 일반적인 마스킹 기법의 (256*8 byte)에 대한 테이블 크기 문제도 (256*6 byte)로 단축시킨다.