• Smart Structures and Systems
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• 제22권4호
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• pp.469-479
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• 2018

The present research study utilizes a multi-objective optimization method for Pareto optimization of an eight-degree of freedom full vehicle vibration model, adopting a non-dominated sorting genetic algorithm II (NSGA-II). In this research, a full set of ride comfort as well as ride safety parameters are considered as objective functions. These objective functions are divided in to two groups (ride comfort group and ride safety group) where the ones in one group are in conflict with those in the other. Also, in this research, a special optimizing technique and combinational method consisting of weighted sum method and Pareto optimization are applied to transform Pareto double-objective optimization to Pareto full-objective optimization which can simultaneously minimize all objectives. Using this technique, the full set of ride parameters of three dimensional vehicle model are minimizing simultaneously. In derived Pareto front, unique trade-off design points can selected which are non-dominated solutions of optimizing the weighted sum comfort parameters versus weighted sum safety parameters. The comparison of the obtained results with those reported in the literature, demonstrates the distinction and comprehensiveness of the results arrived in the present study.

• 대한전자공학회논문지TE
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• 제37권1호
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• pp.58-62
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• 2000

본 논문에서는 독립적인 각각의 정보(Information:이하 Info)를 동시 전송하기 위한 I(동상)-Q(직교상)변조방식을 이용한 변조방식을 제안한다. 각 상에 각각의 정보(Info)의 1비트를 전송하는 경우, QPSK(Quadrature Phase Shift Keying)방식을 적용하고 2비트 이상을 전송할 경우, MAPSK(또는 MQAM)방식을 적용한 변조방식을 제안한다. APSK(Amplitude Phase Shift Keying)방식을 이용한 방식으로 적용된 제안한 QPSK(Quadrature Phase Shift Keying)와 MAPSK(Multiple Amplitude Phase Shift Keying)은 컴퓨터 가상실험으로 분석되었다. CDMA에 적용하기 위해서 MAPSK의 1차 변조파를 전송전에 의사잡음코드(Pseudonoise code)를 사용하여 2차 변조하여 확산한다. 본 논문은 컴퓨터 가상 실험을 통해서 각정보(Info)의 BER 성능을 제시하고 분석한다. 또한 시험용 변조기를 제작하여 확산전후의 전력 스펙트럼에 대해서 분석하였다.

• 전기전자학회논문지
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• 제19권4호
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• pp.472-478
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• 2015

스마트 안심귀가 서비스는 이용하기를 원하는 사용자는 GPS 위치 정보를 제공하는 스마트 기기를 이용하여 이 서비스를 요청한다. 스마트 안심귀가 시스템은 이용자의 위치 정보를 수신한 후, 이용자의 위치 정보를 이용하여 근처의 CCTV 카메라들을 선택하고, 그 이용자를 자동으로 추적하며 촬영하기 위하여 선택된 CCTV 카메라들을 제어한다. 이 서비스는 늦은 밤 귀가하는 경로에 우범지역이 있을 때 유용하게 이용될 수 있다. 기존의 시스템은 다수의 사용자에게 동시에 안심귀가 서비스를 제공할 수 없는 단점을 가지고 있었다. 본 논문에서는 다수의 사용자에게 서비스를 동시에 제공할 수 있는 스마트 안심귀가 시스템을 제안한다.

• 한국통신학회논문지
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• 제16권12호
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• pp.1366-1381
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• 1991

톤간섭과 잡음 환경하에서 m-분포 페이딩 채널을 통해 수신되는 DS/QPSK 신호의 오율식을 유도한 후 이를 수치계산하여 그림으로 나타내어 검토했다. 오율식의 유도는 두 가지 경우에 대하여 행했다. 즉, 하나는 신호만 페이딩의 영향을 받는 경우이고 다른 하나는 신호와 간섭이 동시에 페이딩의 영향을 받는 경우이다. 수치 계산하여 얻어진 결과로부터 신호만 페이딩의 영향을 받는 경우보다 신호와 간섭이 동시에 페이딩의 영향을 받는 경웨 오율특성이 더 열화되는데 직접확산을 이용하면 큰 오율개선이 이루어진다는 것을 알수 있었다. 그러나 그 오율의 개선폭은 간섭과 페이딩의 영향이 약해지면 약해질수록 작아진다는 것을 확인할수 있었다.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권9호
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• pp.521-530
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• 2005

In this paper, a new high resolution reflectometry scheme, time-frequency domain reflectometry(TFDR), isproposed to detect and estimate a fault in a transmission line. Traditional reflectometry methodologies have been achieved either in the time domain or in the frequency domain only. However, the TFDR can jump over the performance limits of the traditional reflectometry methodologies because the acquired signal is analyzed in time and frequency domain simultaneously. In the TFDR, the new reference signal and the novel TFDR algorithm are proposed for analyzing the acquired signal in the time-frequency domain. Because the reference signal of Gaussian envelop chirp signal is localized in the time and frequency domain simultaneously, it is suitable to the analysis in the time-frequency domain. In the proposed TFDR algorithm, the time-frequency distribution function and the normalized time-frequency cross correlation function are used to detect and estimate a fault in a transmission line. That algorithm is verified for real-world coaxial cables which are typical transmission line with different types of faults by the TFDR system composed of real instruments. The performance of the TFDR methodology is compared with that o( the commercial time domain reflectomeoy(TDR) experiments, so that concludes the TFDR methodology can detect and estimate the fault with smaller error than TDR methodology.

• Industrial Engineering and Management Systems
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• 제11권3호
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• pp.288-298
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• 2012

Lot sizing and shipment scheduling are two interrelated decisions made by a manufacturing plant and a third-party logistics distribution center. This paper analyzes a dynamic inbound ordering problem and shipment problem with a freight container cost, in which the order size of multiple products and single container type are simultaneously considered. In the problem, each ordered product placed in a period is immediately shipped by some freight containers in the period, and the total freight cost is proportional to the number of containers employed. It is assumed that the load size of each product is equal and backlogging is not allowed. The objective of this study is to simultaneously determine the lot-sizes and the shipment schedule that minimize the total costs, which consist of production cost, inventory holding cost, and freight cost. Because the problem is NP-hard, we propose three meta-heuristic algorithms: a simulated annealing algorithm, a genetic algorithm, and a new population-based evolutionary meta-heuristic called self-evolution algorithm. The performance of the meta-heuristic algorithms is compared with a local search heuristic proposed by the previous paper in terms of the average deviation from the optimal solution in small size problems and the average deviation from the best one among the replications of the meta-heuristic algorithms in large size problems.

• 한국정보통신학회논문지
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• 제9권8호
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• pp.1821-1827
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• 2005

현재 유선 인터넷 환경에서는 이미지를 표현하기 위하여 대부분 GIF와 JPG를 이용하며, 무선 인터넷 환경에서는 SVG, wBMP, SIS, PNG, Flash Lite 등과 같은 다양한 이미지 파일들을 이용한다. 따라서 유${\cdot}$무선인터넷을 동시에 지원하기 위한 콘텐츠를 제작하는 경우 이중으로 제작비용이 소요되는 문제점이 있다. 이에 본 논문에서는 유무선 인터넷을 동시에 지원할 수 있는 서비스를 재발할 때, SVG를 효율적으로 적용하는 방법을 제안하였다. 유${\cdot}$무선 인터넷을 동시에 지원하는 서비스에 SVG를 이용함으로써 유${\cdot}$무선 인터넷 기반의 콘텐츠를 제작할 때 기업이 지출해야 하는 개발비용을 크게 줄일 수 있다.

• 센서학회지
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• 제22권5호
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• pp.364-368
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• 2013

Vibrational energy harvester based on piezoelectricity has been expected to be the dominant energy harvesting technology due to the advantages of high conversion efficiency, light weight and small size, night operation, etc. Its commercialization is just around the corner but the integration with power management electronics should be solved in advance. In this paper, therefore, fully-integrated design environment for piezoelectric energy harvesting systems is presented to assist co-design with the power management electronics. The proposed design environment is capable of analyzing the energy harvester including the package-induced damping effects and simulating the device and its power management electronics simultaneously. When the developed design environment was applied to the fabricated device, the simulated resonant frequency matched well with the experimental result with a difference of 2.97% only. Also, the complex transient response was completed in short simulation time of 3,001 seconds including the displacement distribution over the device geometry. Furthermore, a full-bridge power management circuit was modeled and simulated with the energy harvester simultaneously. Therefore the proposed, fully-integrated design environment is accurate and fast enough for the contribution on successful commercialization of piezoelectric energy harvester.

• 한국의류학회지
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• 제35권12호
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• pp.1507-1517
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• 2011

Berberine, palmatine, and Phellodendron bark dye was prepared in methanol for HPLC-DAD-MS analysis of liquid dye. Silk was dyed using berberine, palmatine, and Phellodendron bark dye prepared in water. The dye was extracted from the dyed silk using the HCl/methanol/water (2:1:1 v/v/v) solvent system with a slight modification. The liquid dyes and the dye extracted from the silk samples dyed with the three dye sources were examined using the HPLC-DAD-MS analysis to simultaneously detect berberine and palmatine from the plant dye and the dyeings. Colorimetric measurement was carried out using a spectrophotometer to examine the color and the intensities of berberine, palmatine, and Phellodendron bark dyed silk samples. From the liquid dyes, berberine eluted at 5.21 min with the molecular cation m/z=336 and the UV spectrum confirming that the product was berberine. Palmatine eluted at 5.12 min with the molecular cation m/z=352 and the UV spectrum confirming that the product was palmatine. From the silk dyed with berberine and palmatine dye, berberine and palmatine species eluted at 5.35 min and 5.24 min, respectively. From the silk dyed with Phellodendron bark, berberine and palmatine were detected simultaneously at 5.35 min and 5.26 min, respectively. All three dyes had yellow hue while palmatine dyed silk showed the highest hue and chroma. Palmatine dyed silk showed the highest K/S value that indicated the strongest color intensity and the highest dye uptake.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 1993년도 한국우주과학회보 제2권2호
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• pp.21-21
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• 1993

The imaging areas of currently available optical detectors are relatively small to cope with large image areas such as telescope focal Planes. One Possibility to obtain large detection areas is to assemble mosaics of Charge Coupled Devices(CCDs) and drive them simultaneously. Parallel driving of many CCDs together rules out the possibility of individual tuning; however such optimisation is very important when the ultimate low light level performance is required particularly for new devices. In this work, a new concept has been developed for an entirely novel approach where the drive waveforms are multiplexed and interleaved. This simultaneously reduces the number of leadout connections and permits individual optimisation efficiently. The controller has been designed to include one electronic of component produced by CAD software where most of the digital circuits are integrated to minimise the component count and improve the efficiency of the system greatly. The software has an open architecture to permit convenient modificationl by the user to fit their specific purposes. The desire of controller allows great flexibility of system parameters by the softwa re, specifically for the compatibility to deal with any number of mixed CCDs and in any format within the practical limit. The system has been integrated to test the performance and the result is discussed for readout noise, system linearity and cross-talk between the CCDs. The system developed in this work can be applicable not only for astro nomical observation with a telescope but also in other related fields for low light level detection systems such as spectroscopic application, remote sensing and X-ray detecti13n systems with large sensing areas and high resolution.