• Spatial Information Research
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• v.19 no.3
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• pp.95-106
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• 2011

Recently as efficient processing of aggregate queries for fetching desired data from sensors has been recognized as a crucial part, in-network aggregate query processing techniques are studied intensively in wireless sensor networks. Existing representative in-network aggregate query processing techniques propose routing algorithms and data structures for processing aggregate queries. However, these aggregate query processing techniques have problems such as high energy consumption in sensor nodes, low accuracy of query processing results, and long query processing time. In order to solve these problems and to enhance the efficiency of aggregate query processing in wireless sensor networks, this paper proposes Bucket-based Parallel Aggregation(BPA). BPA divides a query region into several cells according to the distribution of sensor nodes and builds a Quad-tree, and then processes aggregate queries in parallel for each cell region according to routing. And it sends data in duplicate by removing redundant data, which, in turn, enhances the accuracy of query processing results. Also, BPA uses a bucket-based data structure in aggregate query processing, and divides and conquers the bucket data structure adaptively according to the number of data in the bucket. In addition, BPA compresses data in order to reduce the size of data in the bucket and performs data transmission filtering when each sensor node sends data. Finally, in this paper, we prove its superiority through various experiments using sensor data.

• Journal of the Korean Electrochemical Society
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• v.11 no.4
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• pp.268-272
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• 2008

$LiFePO_4$ material was synthesized by electrospinning method to obtain optimal particle size($50{\sim}100\;nm$) without carbon coating or ball milling. This material showed an orthorthombic structure with Pnma space group without any impurities, such as FeP or $Fe_2P$, in the XRD pattern. The particle morphology and particle shape were observed by SEM analysis. Li/$LiFePO_4$ cell showed a high initial discharge capacity of 135 mAh/g, at current density of $0.1\;mA/cm^2$ with a cut-off voltage of 2.8 to 4.0V. This cell exhibited a perfect cycle performance over 99.9% cycle retention rate up to 50 cycles.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.121-129
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• 2008

In this paper, we present a fast analysis of multilayer microstrip fractal structure by using the fast multipole method (FMM). In the analysis, accurate spatial green's functions from the real-axis integration method(RAIM) are employed to solve the mixed potential integral equation(MPIE) with FMM algorithm. MoM's iteration and memory requirement is $O(N^2)$ in case of calculation using the green function. the problem is the unknown number N can be extremely large for calculation of large scale objects and high accuracy. To improve these problem is fast algorithm FMM. FMM use the addition theorem of green function. So, it reduce the complexity of a matrix-vector multiplication and reduce the cost of calculation to the order of $O(N^{1.5})$, The efficiency is proved from comparing calculation results of the moment method and Fast algorithm.

• KOMUNHWA
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• no.68
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• pp.25-39
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• 2006

This article attempts to define identity, role and functions of a university museum and to suggest specialization of the university museum in the perspective of culture, arts, and science. A university museum is defined as a center for the service of the university community and its development which acquires, researches, communicates, exhibits and educates, for purposes of eduinfotainment,29 material evidence of people and their environment. The target user of the today's university museum are not only professors, students, university workers, but also university neighbourhood such as the related professionals, patrons, parents, school children and villagers. A multi-dimensional and multi-purpose university museum can be established and managed in a real world and / or a cyber world in the perspective of culture, arts, and science. Based on a ubiquitous system30 in a cyber world vis-a-vie a real world, the university museum can be easily utilized by users anywhere, anytime and any device. In order to specialize the university museum in the perspective of culture, arts and science, it is desirable that the university museum director with the CEO of the university community promote the specialization of the university museum based on philosophy and strategies of university community management after they definitely evaluate the components and resources of the university museum such as human powers, museum collections, organizational, technological, capital, spacial and symbolic resources, The specialization of the university museum should be projected and executed in the direction of maintaining the typical scope of museum activities and managing the effective museum management. Specializing the university museum in the perspective of culture, arts, and science can contribute not only to establish the identity of the university community and to perform role and functions of the university museum but also to encourage academic development, to revaluate the brand of the university community and to promote the marketing for the university.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.4
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• pp.409-416
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• 2011

A mobile emission laboratory (MEL) was designed to measure the amount of traffic pollutants with high temporal and spatial resolution under real conditions. Equipment for gas-phase measurements of quantity of CO, NOx, $CO_2$, and THC and for the measurement of the number density and size distribution of fine and ultra-fine particles by a FMPS and a CPC were placed in a mini-van. The exhaust of different type of vehicles can be sampled by MEL. This paper describes the construction and technical details of the MEL and presents data from the experiment in which a car chases city buses fuelled by diesel, CNG, and LPG. The diameters of most particles in the exhaust of the diesel city bus were less than 300 nm and most of the particles had a diameter of 30-60 nm. However, most particles in the exhaust of the CNG and LPG city buses were nanoparticles (diameter: less than 50 nm).

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.787-796
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• 2012

This study, as a purpose of viewshed anaiysis is selected for the view route, View of the target yunseondo wonlim (scenic sites No.34) located in the terrain ridge. Using GIS Viewshed analysis carried out and the results reflect the view route was selected. The basic research for this study, the scenic sites such as the natural and cultural resources for the efficient and optimized to create the route view. Viewshed Analysis results could be summarized as follows: Along a scenic sites located inside the main ridge Viewshed analysis was carried out. This overlapping the cumulative results are Leading to Nakseojae(樂書齎) Seyeonjeong(洗然亭) from space in the visible frequency higher natural villages of the district. Selected the view route and were on the road and in the topographic map nesting along Visible high-frequency region. Based on the results of the nested Viewshed major selected six points Viewshed analysis was carried out. Resource for the surrounding landscape. Results determine whether the visibility of the surrounding landscape was identified as the viewable area appears good. Finally Viewshed Analysis results for six points in the final review.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.04a
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• pp.86-92
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• 1993

자동차의 현가장치에 대한 능동제어연구는 국내외적으로 활발히 진행되어 왔다. 수동식현가장치는 단순히 스프링과 감쇠기로 차체의 진동을 수동 제어 하므로 성능 향상에 한계가 존재하게 된다. 수동식 현가장치가 강성계수와 감쇠계수를 조절함으로써 차체로 들어오는 진동을 억제하는 반면, 능동식제 어는 보통 유압을 이용하여 효율적으로 차체에 들어오는 진동을 억제시키게 된다. 일반적으로 자동차가 능동현가장치 설계시 요구되는 사항은 탑승자의 승차감, 조종성, 현가장치의 공간확보 문제, 경제성(제어력), 실제적으로 자동 차에 적용할 수 있는 능동제어기법인가 하는 문제이다. 자동차 능동식 현가 장치는 보통 1/4 car (2자유도계), Full-car 모델 (7자유도계) 등으로 모델링 을 하여 능동제어기를 설계한다. 1/4 car 모델의 특징은 해석이 비교적 단순 하고 현가장치의 동적거동을 이해하는데 유용하고 실험을 하거나 실제 자동 차에 적용하기 쉬운 반면에 Full-car 모델에 비해 제어력의 효율이 떨어진다 는 단점이 있다. 그 이유는 1/4 car 모델은 차체의 동역학적 특성을 고려하 여 설계하지 않았기 때문에 4개의 독립현가차축에서는 오직 그 현가축방향 으로 발생하는 수직방향의 진동만을 제어하기 때문이다. 따라서 동역학적 역 성에 기인하는 운동을 제어하는 비효율적인 제어력이 공급된다는 단점을 갖 는다. 이에 비해 full-car 모델은 주행모드(수직, 롤링, 피칭운동)간의 연성을 고려하여 제어기를 설계할 수 있기 때문에 1/4 car 모델에 비해 제어력의 효 율이 높다는 장점이 있는 반면에 모델이 수학적으로 복잡하므로 제어력을 구하는데 계산량이 많고, 실제 자동차에 적용하기에 복잡하다는 단점을 갖고 있다. 따라서 본 논문에서는 쉽게 실험할 수 있고, 실용화할 수 있는 1/4 car 모델에 대하여 능동제어기를 설계하여 실제자동차에 능동제어기를 적용할 때 참고가 될 수 있도록 하였다. 자동차는 저주파영역의 밴드통과필터 역할 을 하므로 저주파에서의 성능, 특히 탑승자가 민감하게 느끼는 0.5Hz - 10Hz 부근의 주파수성능은 승차감, 조종성에 상당히 중요하다. 이에 본 논문 에서는 0.5Hz - 10Hz 부근의 승차감, 조종성의 향상에 초점을 두고 차체의 속도를 출력변수로 한 LQG/LTR 제어기를 설계하였다. LQG/LTR 설계기법 은 안정도-강인성이 좋은 체계적인 설계기법으로서 전 상태를 측정할 필요 가 없으므로 실제 적용시 효과적이다. 또한 자동차의 제원의 변화에 대한 고 유치의 민감도해석과 새로운 개념으로 안정도-강인성(Robustness)해석을 하 여 수동시스템과 능동시스템의 강인성을 비교하였다.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.5
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• pp.291-298
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• 2015

An array type probe for monitoring metal tubes is proposed in this paper which utilizes peak value and peak time of a pulsed eddy current(PEC) signal. The probe consists of an array of encircling coils along a tube and the outside of coils is shielded by ferrite to prevent source magnetic fields from directly affecting sensor signals since it is the magnetic fields produced by eddy currents that reflect the condition of metal tubes. The positions of both exciter and sensor coils are consecutively moved automatically so that manual scanning is not necessary. At one position of send-receive coils, peak value and peak time are extracted from a sensor PEC signal and these data are accumulated for all positions to form an array type peak value signal and an array type peak time signal. Numerical simulation was performed using the backward difference method in time and the finite element method for spatial analysis. Simulation results showed that peak value increases and the peak appears earlier as the defect depth or length increases. The proposed array signals are shown to be excellent in reflecting the defect location as well as variations of defect depth and length within the array probe.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.150-161
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• 2013

This paper presents a new system which produces high resolution 3D contents by capturing multiview images of an object using multiple cameras, and estimating geometric and texture information of the object from the captured images. Even though a variety of multiview image-based 3D reconstruction systems have been proposed, it was difficult to generate high resolution 3D contents because multiview image-based 3D reconstruction requires a large amount of memory and computation. In order to reduce computational complexity and memory size for 3D reconstruction, the proposed system predetermines the regions in input images where an object can exist to extract object boundaries fast. And for fast computation of a visual hull, the system represents silhouettes and 3D-2D projection/back-projection relations by chain codes and 1D homographies, respectively. The geometric data of the reconstructed object is compactly represented by a 3D segment-based data format which is called DoCube, and the 3D object is finally reconstructed after 3D mesh generation and texture mapping are performed. Experimental results show that the proposed system produces 3D object contents of $800{\times}800{\times}800$ resolution with a rate of 2.2 seconds per frame.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.239-246
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• 2003

BPR(Business Process Re-engineering)은 업무 프로세스를 혁신적으로 재설계 함으로써 급속한 외부환경과 내부환경의 변화에 능동적으로 대처하고자 하는 기업의 경영혁신 기법, 조직 재설계의 수단으로 도입되었다. 해마다 시행되고 있는 정보화평가위원회의 국가 정보화 사업에 대한 평가는 정보화 사업의 성과관리에 있어 BPR에 따른 조직과 제도개선 성과를 포함하여 제도혁신에 대한 인센티브 제공 둥 조직과 제도혁신 강화의 필요성이 강하게 주장되는 등 BPR은 공공부문으로 점차 확대 될 추세이다. 본 연구는 조직적 문제의 해결을 통하여 지방자치단체 GIS의 효율성을 제고 하고자 하는 목적으로 출발하였다. 따라서 BPR의 이론적 고찰을 통하여 지자체 GIS BPR의 개념을 정의하고, 지방자치단체의 GIS 시스템 도입 이후의 업무 프로세스의 변화, 업무 변화의 양상, 잠재적 업무 효과를 BPR의 기법을 통해 보여줌으로써 조직 재설계의 수단으로 GIS BPR의 가능성을 모색하였다. 이는 GIS 발달 단계에 따른 효과 창출의 패러다임을 고려한 지방자치단체 GIS 업무의 변화를 수용하는 능동적이고 융통성 있는 조직 모형을 찾는 것이라 할 수 있다. 따라서 단위조직, 진화조직, 전체조직의 GIS 발달 단계에 따른 지방자치단체 GIS 조직 모형을 규정하였다. 본 연구를 통한 시사점은 지방자치단체 GIS 조직이 현재의 단위조직 수준에서 진화조직의 단계를 걸쳐 전체조직으로 향하는 가능성을 제시했다는 점이다. 이는 지방자치단체가 각각의 단계에서 GIS의 도입 효과를 창출하기 위하여 충실히 수행해 할 것이 무엇인지를 BPR을 통해 조직적 차원에서, 그리고 조직이 다루는 업무영역의 차원에서 접근했다는 점에서 그 의의가 있다. 본 연구의 결과를 통해 지방자치단체 GIS 기본계획에 있어 조직 측면의 장기적 비전의 제시가 가능하며 이를 통해 보다 성숙된 GIS 사업의 추진과 효율적인 시스템의 운영이 가능할 것이다.. 이상의 결과를 종합해볼 때, ${\beta}$-glucan은 고용량일 때 직접적으로 또는 $IFN-{\gamma}$ 존재시에는 저용량에서도 복강 큰 포식세로를 활성화시킬 뿐 아니라, 탐식효율도 높임으로써 면역기능을 증진 시키는 것으로 나타났고, 그 효과는 crude ${\beta}$-glucan의 추출조건에 따라 달라지는 것을 알 수 있었다.eveloped. Design concepts and control methods of a new crane will be introduced in this paper.and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. On the basis of the simplified model, the simulation was performed and the results could be confirmed by the experiments under various conditions.뢰, 결속 등 다차원의 개념에 대한 심도 깊은 연구와 최근 제기되고 있는 이론의 확대도 필요하다. 마지막으로 신뢰와 결속에 영향을 미치는 요소간의 개념적 분류, 차이의 검증, 영향력 등