• 정보보호학회논문지
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• 제19권2호
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• pp.11-21
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• 2009

NTRU는 1990년대 Hoffstein 등에 의해 제안된 격자(Lattice) 기반 공개키 암호체계로서 기존의 공개키 암호와 비교하여 동일한 안전성을 제공하면서 암호화 및 복호화 속도가 빠르며 양자 연산 알고리즘을 이용한 공격에도 강하다는 이점이 있어 많은 주목을 받고 있다. 본 논문에서는 단순 전력 분석 공격과 통계적 특성을 이용한 전력 분석 공격인 상관계수 전력 분석 공격에 대한 NTRU의 안전성을 분석하고, NesC로 구현한 NTRU의 연산을 Telos 모트(mote)에서 수행시켜 측정한 전력 소모 데이터에 상관계수 전력 분석 공격을 적용하여 개인키 정보를 복원하는 실험 결과를 보인다. 또한 이러한 전력 분석 공격을 방지하기 위한 대응 방법을 제시한다. 먼저, 단순 전력 분석 공격을 방지하기 위해 연산 결과를 저장할 배열을 0이 아닌 수로 초기화시키는 방법을 제안하고, 통계적 특성을 이용한 전력분석 공격을 방지하기 위해 연산 순서를 변경하거나 컨볼루션(convolution) 연산에 사용되는 피연산자들에게 무작위성(randomness)을 부여하여 같은 입력에 대해서 랜덤한 전력 소모를 보이도록 하는 방법을 제안한다.

• 한국항행학회논문지
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• 제26권6호
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• pp.434-440
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• 2022

ICAO (international civil aviation organization)에서는 전략적인 의사결정과 항공교통관리 평가를 위해 세계항행계획인 GANP (global air navigation plan) 수행을 체약국에게 권고하였다. 본 연구에서는 항공교통관리 평가를 위해 제시된 KPI (key performance indicator) 05 실제 항로 연장에서 항로거리를 구하는 새로운 방법을 제안하였다. 이를 위해 한 달간의 항적 데이터를 수집하고 ICAO에서 제시한 방법과 본 저자가 제시하는 방법으로 각각 항로거리를 산출하였다. ICAO 방법은 반경 40 NM 원형에 대한 원의 방정식과 항적 데이터 내 원에 근접한 내·외부 지점에 대한 직선의 방정식을 통하여 교점을 추정하여야 하고, 네 가지의 비행거리를 계산하여 항로거리를 산출한다. 본 연구에서 제시한 방법은 교점을 추정하지 않고 두 가지의 비행거리를 계산하여 항로거리를 산출한다. 두 방법의 오차를 확인하기 위해 회귀모형 성능평가지표인 RMSE (root mean square error)와 결정계수 R² 를 사용하였다.

• Transactions on Electrical and Electronic Materials
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• 제7권5호
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• pp.247-251
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• 2006

The traction DC feeder cable is one of the key devices for the safety operation of subway system, but for low voltage DC feeder cable (<3000 V) for subway, little attention has been paid by investigators on its online monitoring technology. With an introduction of cable laying and operation environment for the cable, this paper investigated the on-line monitoring technology of 1500 V DC feeder cable of subway. Firstly, in the text, the fault model of 1500 V DC cable was proposed based on the analysis of the fault type of the DC feeder cable, and then put forward synthetically on-line monitoring discharge signal and DC leakage current signal to assess DC feeder cable insulating state. The results of laboratory experiment prove that the proposed methods are feasible and can be implemented on-line monitor on DC feeder cable of subway.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.635-638
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• 2002

Blowfish is a symmetric block cipher that can be used as a drop-in replacement fur DES or IDEA. It takes a variable-length key, from 32bit to 448bit, making it ideal for both domestic and exportable use. This paper is somewhere middle-of-the-line, where this paper made significant tradeoffs between speed, size and ease of implementation. The main focus was to make an implementation that was usable, moderately compact, and would still run at an acceptable clock speed. For the real time process of blowfish, it is required that high-speed operation and small size hardware. So, A structure of new adders constructed in this study has all advantages abstracted from other adders. As for this new adder, area cost increases by 1.06 times and operation speed increases by 1.42 times.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.169-172
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• 2000

This paper describes design of cryptographic processor which can execute SEED, DES, and triple DES encryption algorithm. To satisfy flexible architecture and area-efficient structure, the processor has I unrolled loop structure with hardware sharing and can support four standard mode, such as ECB, CBC, CFB, and OFB modes. To reduce overhead of key computation, the precomputation technique is used. Also to eliminate increase of processing time due to data input and output time, background I/O technique is used which data input and output operation execute in parallel with encryption operation of cryptographic processor. The cryptographic processor is designed using 2.5V 0.25 $\mu\textrm{m}$ CMOS technology and consists of about 34.8K gates. Its peak performances is about 250 Mbps under 100 Mhz ECB SEED mode and 125 Mbps under 100 Mhz triple DES mode.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2001년도 춘계학술대회 논문집
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• pp.20-25
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• 2001

In recent years, the concern about a user center design in increasing, and it's needed to task a user's visual cognitive characteristics for information presentation. Then this study aims to grasp user's cognitive characteristics about the information presentation by analyzing the fixation points. In the experiment, actually subject operated a copy machine. Recorded the fixation point movement of the operation panel by the eye mark recorder. Analysis examined the screen interface of the operation panel from the field of a fixation point trace. The top down type fixation oder by experience or the context became clear as a result. Furthermore, the difference of the fixation order by skill level was also examined. In this study, it was assumed that to grasp the visual cognitive characteristics becomes the key of efficient information.

• 한국IT서비스학회지
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• 제10권3호
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• pp.213-236
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• 2011

Mobile devices are widely accepted as a convenient machine which provides computing capability as well we cell phone capability. Because of limited resources on mobile devices, complex applications could not be deployed on the devices. Service-based mobile applications (SMAs) can provide a solution to overcome the limitation by subscribing cloud services. Since SMAs have complex structures than standalone applications, it is challenging to develop high quality SMAs, to manage both services and mobile applications, and to implement automated billing for subscribed services. Therefore, there is a great demand for a platform for super mobile computing, which supports all key activities in managing life cycle of SMAs. In this paper, we present technical aspects of a platform which is under development; Super Mobile Autonomous Reliable plaTform (SMART). We believe that it provides a number of practical features which are essential in supporting life-cycle of SMAs; development, deployment, management, and operation.

• 한국정밀공학회지
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• 제30권5호
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• pp.467-473
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• 2013

Diverse approaches for reducing the total energy consumption of machine tools have been introduced and developed, to cope with rapid increase of total energy costs in world-wide manufacturing industries. To realize the improvement of the energy efficiency, systematic and integrated strategies must be considered, including energy-saving design, optimized control operation and concrete evaluation of the energy efficiency. This paper proposes key enabling technologies required to improve the energy efficiency of 5-axis multi-functional machining tools, considering both of system design and operation in the real production environments. Related standardized procedures of the energy efficiency evaluation is also represented.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.551-554
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• 2002

The paper discusses new approach for machining operation simulation using enhanced Z map algorithm. To extract the required geometric information from NC code, suggested algorithm uses supersampling method to enhance the efficiency of a simulation process. By executing redundant Boolean operations in a grid cell and averaging down calculated data, presented algorithm can accurately represent material removal volume though tool swept volume is negligibly small. Supersampling method is the most common form of antialiasing and usually used with polygon mesh rendering in computer graphics. The key advantage of enhanced Z map model is that the data structure is same with conventional Z map model, though it can acquire higher accuracy and reliability with same or lower computation time. By simulating machining operation efficiently, this system can be used to improve the reliability and efficiency of NC machining process as well as the quality of the final product.

• 한국항공운항학회지
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• 제19권2호
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• pp.37-44
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• 2011

This paper summarizes the HVO concept and procedures, presents a summary of the research and results, and outlines areas where future HVO is required. This concept enables people to get their destinations through shortest paths with advanced air traffic control system and equipments. The concept's key feature is that pilots maintain their own separation from other aircraft using air-to-air datalink and on-board software which are needed for supporting flight information present on the high Way in the sky display and airborne internet. By assigning Self-Controlled Area which assume pilot have separation responsibility, controllers evaluated SATS HVO concept as a successful method on the view of reduced workload and increased traffic level on high volume operation.