• Journal of Information Processing Systems
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• 제16권3호
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• pp.639-647
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• 2020

In the vibration target localization algorithms based on time difference of arrival (TDOA), Fang algorithm is often used in practice because of its simple calculation. However, when the delay estimation error is large, the localization equation of Fang algorithm has no solution. In order to solve this problem, one dimensional search location algorithm based on TDOA is proposed in this paper. The concept of search is introduced in the algorithm. The distance d1 between any single sensor and the vibration target is considered as a search variable. The vibration target location is searched by changing the value of d1 in the two-dimensional plane. The experiment results show that the proposed algorithm is superior to traditional methods in localization accuracy.

• 한국컴퓨터정보학회논문지
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• 제23권12호
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• pp.73-80
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• 2018

Certification revocation list(CRL) is needed for excluding compromised, faulty, illegitimate vehicle nodes and preventing the use of compromised cryptographic materials in vehicular communications. It should be distributed to vehicles resource-efficiently and CRL computational load of vehicles should not impact on life-critical applications with delay sensitive nature such as the pre-crash sensing that affords under 50msec latency. However, in the existing scheme, when a vehicle receives CRL, the vehicle calculates linkage values from linkage seeds, which results in heavy computational load. This paper proposes, a new CRL distribution scheme is proposed, which minimizes the time for CRL processing of vehicles. In the proposed scheme, the linkage value calculation procedure is performed by road-side unit(RSU) instead of the vehicle, and then the extracted linkage values are relayed to the vehicle transparently. The simulation results show that the proposed scheme reduces the CRL computational load dramatically, which would minimize impact on life-critical applications' operations with low latency.

• 한국전자파학회논문지
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• 제16권10호
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• pp.995-1002
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• 2005

Orthogonal frequency division multiplexing(OFDM) 시스템은 peak-to-average power ratio(PAR) 문제를 가진다. 일반적으로, partial transmit sequence(PTS) 기법을 이용하여 최적의 PAR 감소 성능을 얻기 위해서는 나눈 부블록의 수와 위상 요소(phase factor)에 관한 모든 탐색을 해야 한다 나눈 부블록 수와 위상 요소 수가 많을수록 PAR 감소 성능은 더 개선되지만, 계산량 또한 부블록 수에 따라 지수적으로 증가하여 송신기의 복잡도와 처리시간지연을 초래한다. 따라서 전송되는 신호의 PAR을 최적에 가깝게 줄이면서 동시에 계산량도 함께 줄일 수 있는 기법이 요구된다. 본 논문에서는 PTS 기법에서 최적의 PAR 감소 성능을 갖는 위상 요소를 찾기 위해 최적화 문제에 많이 사용되고 있는 유전자 알고리즘(Genetic Algerian: GA)을 이용함으로써 PAR 문제를 해결하고, 동시에 계산량도 함께 감소시켜 송신기의 복잡도와 처리시간 지연을 줄이는 기법을 제안하며, 제안된 기법의 PAR 감소 성능과 계산량을 기존의 제안된 방법들과 비교하였다. 또한, 본 논문에서 제안한 기법이 적은 계산량으로도 일반기법에 더 가까운 PAR 감소 성능을 가짐을 보였다.

• 한국BIM학회 논문집
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• 제14권2호
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• pp.25-34
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• 2024

This study proposes a new methodology to increase the flexibility and efficiency of the design data evaluation system by combining Building Information Modeling (BIM) technology in the architectural industry, OpenAI's interactive artificial intelligence, and ChatGPT. BIM technology plays an important role in digitally modeling and managing architectural information. Since architectural information is included, research and development are underway to review and evaluate BIM data according to conditions through program development. However, in the process of reviewing BIM design data, if the review criteria or evaluation criteria according to design change occur frequently, it is necessary to update the program anew. In order for designers or reviewers to apply the changed criteria, requesting a program developer will delay time. This problem was studied by using ChatGPT to modify and update the design data evaluation program code in real time. In this study, it is aimed to improve the changing standards and accuracy by enabling programming non-professionals to change the design regulations and calculation standards of the BIM evaluation program system using ChatGPT. In this study, in the BIM-based design certification automation evaluation program, a program in which the automation evaluation method is being studied based on the design certification evaluation manual was first used. In the design certification automation evaluation program, the programming non-majors checked the automation evaluation code by linking ChatGPT, and the changed calculation criteria were created and modified interactively. As a result of the evaluation, the change in the calculation standard was explained to ChatGPT and the applied result was confirmed.

• Journal of Information Processing Systems
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• 제7권2호
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• pp.241-260
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• 2011

In earlier days, most of the data carried on communication networks was textual data requiring limited bandwidth. With the rise of multimedia and network technologies, the bandwidth requirements of data have increased considerably. If a network link at any time is not able to meet the minimum bandwidth requirement of data, data transmission at that path becomes difficult, which leads to network congestion. This causes delay in data transmission and might also lead to packet drops in the network. The retransmission of these lost packets would aggravate the situation and jam the network. In this paper, we aim at providing a solution to the problem of network congestion in mobile ad hoc networks [1, 2] by designing a protocol that performs routing intelligently and minimizes the delay in data transmission. Our Objective is to move the traffic away from the shortest path obtained by a suitable shortest path calculation algorithm to a less congested path so as to minimize the number of packet drops during data transmission and to avoid unnecessary delay. For this we have proposed a protocol named as Congestion Aware Selection Of Path With Efficient Routing (CASPER). Here, a router runs the shortest path algorithm after pruning those links that violate a given set of constraints. The proposed protocol has been compared with two link state protocols namely, OSPF [3, 4] and OLSR [5, 6, 7, 8].The results achieved show that our protocol performs better in terms of network throughput and transmission delay in case of bulky data transmission.

• 제어로봇시스템학회논문지
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• 제18권12호
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• pp.1079-1085
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• 2012

For precise motion control, S-curve velocity profile is generally used but it has disadvantage of relatively long calculation time for floating-point arithmetics. In this paper, we present a new generating method for velocity profile to reduce delay time of profile generation so that it overcomes such disadvantage and enhances the efficiency of precise motion control. In this approach, the velocity profile is designed based on the gamma correction expression that is generally used in image processing to obtain a smoother movement without any critical jerk. The proposed velocity profile is designed to support both T-curve and S-curve velocity profile. It can generate precise profile by adding an offset to the velocity profile with decimals under floating point that are not counted during gamma correction arithmetic operation. As a result, the operation time is saved and the efficiency is improved. The proposed method is compared with the existing method that generates velocity profile using ring buffer on a 8-bit low-cost MCU. The result shows that the proposed method has no delay in generating driving profile with good accuracy of each cycle velocity. The significance of the proposed method lies in reduction of the operation time without degrading the motion accuracy. Generated driving signal also shows to verify effectiveness of the proposed method.

• 한국건설관리학회논문집
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• 제18권2호
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• pp.30-37
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• 2017

공기연장과 관련한 많은 연구에도 불구하고 국내 공공 공사의 공기연장 추가간접비 산정방법에 대한 구체적인 연구가 없어 쟁점이 심화되고 있다. 또한 명확한 산정기준이 마련되지 않아 산정방식이 여러 가지로 혼용되고 있으며 타당성을 갖는 산정방식에 대한 고찰을 담은 연구가 없는 실정이다. 특히 장기계속계약에서의 휴지기발생시 추가간접비와 관련된 연구는 전무하다. 본 연구는 공사기간 동안 발생하는 비용의 패턴을 고려하여 국내 공공 공사의 특성을 반영한 공기연장 간접비 산출 방식을 제시하기 위해 현행 공기연장 간접비 산정 기준을 고찰하고 실태를 조사한 후 실제 사용되는 산정방식을 모형사례에 적용하여 그 산출결과를 비교 고찰하였다. 그 결과를 통해 기존 산정방식에 대한 문제점을 고찰하였으며, 기존 산정방식의 문제점을 고찰하는 과정에서 장기계속계약공사의 휴지기로 인한 추가간접비 산정에 적합한 산정방식인 '공사중지기간 총 실비산정방법'을 제시하였다.

• 한국자동차공학회논문집
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• 제21권2호
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• pp.37-44
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• 2013

Generally, a reduced chemical mechanism of n-heptane is used as chemical fuel of a 3-D diesel engine simulation because diesel fuel consists of hundreds of chemical components and various chemical classes so that it is very complex and large to use for the calculation. However, the importance of fuel in a 3-D simulation increases because detailed fuel characteristics are the key factor in the recent engine research such as homogeneous charged compression ignition engine. In this study, normal paraffin, iso paraffin and aromatics were selected to represent diesel characteristics and n-dodecane was used as a representative normal paraffin to describe the heavy molecular weight of diesel oil (C10~C20). Reduced kinetics of iso-octane and toluene which are representative species of iso paraffin and aromatics respectively were developed in the previous study. Some species were selected based on the sensitivity analysis and a mechanism was developed based on the general oxidation scheme. The ignition delay times, maximum pressure and temperature of the new reduced n-dodecane chemical mechanisms were well matched to the detailed mechanism data.

• 대한전자공학회논문지SD
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• 제46권11호
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• pp.66-76
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• 2009

움직임 추정은 영상 부호화 시스템에서 큰 비중을 차지하는 부분으로, 실시간 동작을 위해서는 효율적인 구조를 필요로 한다. 따라서 H.264 전체 시스템을 위한 움직임 추정기 블록의 구현은 부호화 과정을 고속으로 수행할 수 있도록 별도의 전용 하드웨어 모듈로 설계하는 것이 바람직하다. 본 논문에서는 많은 연산량을 효율적으로 줄일 수 있도록 병렬 처리를 바탕으로 움직임 추정 감지 블록, 41개의 SAD(Sum of Absolute Difference)값 계산 블록, 최소의 SAD값 계산과 움직임 벡터 생성 블록을 제안하고자 한다. 움직임 추정 감지 블록과 최소의 SAD값 계산기에서는 선계산(pre-computation) 방법을 적용함으로써, 입력 Switching Activity를 줄여 고속 구현이 가능하도록 하였으며, 움직임 추정 감지 블록과 41개의 SAD값 계산 블록에서 가장 많은 부분을 차지하는 가산기 구조를 일반적으로 사용되는 Ripple Carry Adder 대신에 Carry Skip Adder를 적용함으로써, Adder Tree 구조를 고속으로 처리할 수 있도록 하였다. 또한 외부에서 탐색 영역 제어와 같은 주요 변수를 쉽게 제어할 수 있도록 하여, 하드웨어 구조의 효율성을 높였다. 시뮬레이션 및 FPGA 검증 결과, 움직임 추정기의 임계 경로를 발생시키는 MED블록에서 일반적인 구조를 적용했을 때보다 19.89%의 Delay 감소 효과를 얻을 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2503-2508
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• 2005

In this paper, we propose a new discrete-time predictive current controller for a PMSM(Permanent Magnet Synchronous Motor). The main objectives of the current controllers are to ensure that the measured stator currents tract the command values accurately and to shorten the transient interval as much as possible, in order to obtain high-performance of ac drive system. The conventional predictive current controller is hard to implement in full digital current controller since a finite calculation time causes a delay between the current sensing time and the time that it takes to apply the voltage to motor. A new control strategy in this paper is seen the scheme that gets the fast adaptation of transient current change, the fast transient response tracking. Moreover, the validity of the proposed method is demonstrated by numerical simulations and the simulation results will present the improvements of predictive controller and accuracy of the current controller.