• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.31-40
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• 2017

This paper deals with the high precision of GPS measurement reduction and its implementation on near real-time and kinematic mode for those applications requiring centimeter-level precision of the estimated coordinates, even if target stations are a few hundred kilometers away from their references. We designed the system architecture, data streaming and processing scheme. Intensive investigation was performed to determine the characteristics of the GPS medium-range functional model, IGS infrastructure and some exemplary systems. The designed system consisted of streaming and processing units; the former automatically collects GPS data through Ntrip and IGS ultra-rapid products by FTP connection, whereas the latter handles the reduction of GPS observables on static and kinematic mode to a time series of the target stations' 3D coordinates. The data streaming unit was realized by a DOS batch file, perl script and BKG's BNC program, whereas the processing unit was implemented by definition of a process control file of BPE. To assess the functionality and precision of the positional solutions, an experiment was carried out against a network comprising seven GPS stations with baselines ranging from a few hundred up to a thousand kilometers. The results confirmed that the function of the whole system properly operated as designed, with a precision better than ${\pm}1cm$ in each of the positional component with 95% confidence level.

• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.31-40
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• 2012

u-GIS DSMSs have been researched to deal with various sensor data from GeoSensors in ubiquitous environment. Also, they has been more important for high availability. The data from GeoSensors have some characteristics that increase explosively. This characteristic could lead memory overflow and data loss. To solve the problem, various load shedding methods have been researched. Traditional methods drop the overloaded tuples according to a particular criteria in a single server. Tuple deletion sensitive queries such as aggregation is hard to satisfy accuracy. In this paper a dual processing load shedding method is suggested to improve the accuracy of aggregation in clustering environment. In this method two nodes use replicated stream data for high availability. They process a stream in two nodes by using a characteristic they share stream data. Stream data are synchronized between them with a window as a unit. Then, processed results are merged. We gain improved query accuracy without data loss.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.352-360
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• 2008

Recently Task Group (TG) 4 of the Institute of Electrical and Electronics Engineers (IEEE) 802.15a has been recommended a system with ranging capability in existence of multiple Simultaneous operating piconets (SOPs) as well as low-cost, low-power. According to the ranging service, coherent and non-coherent based ranging schemes using ternary code have been adopted as a standard. However it is hard to estimate an accurate time of arrival (TOA) in case of using direct sequence based TOA estimation method because pulse repetition interval (PRI) offered by TG is more limited than the maximum excess delay (MED) of channel. To mitigate inter pulse interference (IPI) problem, this paper proposes a non-coherent TOA estimation scheme using non-periodic transmission (NPT) pattern. The proposed receiver is based on a non-coherent energy detection considering with motivation of low rate wireless personal area network (LR-WPAN). TOA information is estimated via proper comparison with a prescribed threshold after the sliding correlation and search back window (SBW) process for reducing TOA error. To verify the performance of proposed ranging scheme, two distinct channel models approved by IEEE 802.15.4a TG are considered. According to the simulation results, we could conclude that the proposed scheme have performed better performance than the conventional method on the existence of multiple SOPs.

• Journal of the Korean Society of Radiology
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• v.6 no.2
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• pp.83-91
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• 2012

The obesity is a medical condition in which excess body fat has accumulated to the extent. It may have an adverse effect on health, leading to reduced life expectancy and increased health problems such as lifestyle disease, hypertension, and diabetes. Furthermore, it may cause the mental illness such as depression, bipolar disorder, anorexia, hyperphagia, and so on by shrinking psychologically. So, it is regarded as the serious worldwide social problem. Recently, although there are many general obesity care methods with various approaches, these can't be the radical obesity care because of the side effects such as surgery aftereffect, drug addiction, and so on. For these reasons, a methodical approach with a consideration of individual obesity pattern is strongly demanded. In this study, complex obesity care and management system which is overcome the weakness of non-surgical obesity treatment is proposed. And the individually adapted obesity treatment system with the far-infrared therapy module, oxygen therapy module, color therapy module, and microwave therapy module was developed. The complex obesity treatment system which is proposed in this study, could improve the efficiency of treatment by suggesting the various treatment protocols. And proposed system could be the foundation of the high quality obesity treatment system.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.79-79
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• 2010

저온용 무연 솔더의 대표 조성으로 고려되고 있는 Sn-58Bi(융점: $138^{\circ}C$) 공정(eutectic) 조성은 우수한 강도에도 불구하고 연성(ductility) 측면에서의 문제점이 지속적으로 보고되고 있다. 따라서 이 합금계의 연성을 최대로 개선시킬 수 있으면서도 실제 상용화가 가능한 합금 조성의 개발 연구가 요청된다. 본 연구에서는 Sn-Bi 2원계 조성에서 최대의 연성을 나타내는 것으로 보고된 Sn-40Bi 조성에 미량의 합금원소를 첨가함으로써 최대의 연성을 확보하는 한편, 그 연성 특성이 변형속도에 어느 정도 민감한지를 인장 실험을 통해 결정하고자 하였다. 합금원소로는 0.1~0.5 wt%의 Ag, Mn, In, Cu를 선택하였으며, 인장 시편을 제조하여 $10^{-2}$, $10^{-3}$, $10^{-4}\;s^{-1}$의 3종류로 변형속도를 변형시켜가며 응력-변형 곡선(stress-strain curve)을 측정하였고, 조성별, 변형속도별로 최대인장강도(ultimate tensile stress, UTS) 및 연신율 결과들을 정리하였다. 합금원소를 첨가한 조성의 경우는 모든 시험 조건에서 Sn-40Bi보다 우수한 연신률을 나타내는 것으로 측정되었으나, $10^{-2}\;s^{-1}$의 빠른 변형속도에서는 그 향상 정도가 상대적으로 감소하는 경향이 관찰되었다. 특히 Sn-40Bi-0.5Ag 조성의 경우 느린 변형속도에서 특히 눈에 띄는 연신률 값을 나타내며, 모든 변형속도 조건에서 가장 우수한 연성을 나타내었다. 한편 Sn-40Bi-0.1Cu 조성의 경우 변형속도에 따른 연신률의 변화 정도, 즉, 변형속도에 따른 연신률의 민감도가 매우 커 $10^{-4}\;s^{-1}$ 속도에서는 Sn-40Bi-0.5Ag에 버금가는 연신률 값이 측정되었으나, $10^{-2}\;s^{-1}$ 속도에서는 가장 나쁜 연신률 특성을 보여주었다. Sn-40Bi-0.2Mn 조성은 최고의 연신률 향상 특성을 나타내지는 않았으나, In을 첨가한 경우보다는 대체적으로 우수한 연성을 나타내었다. 이상의 각 합금별 연성 특성은 인장시험 전의 미세조직 관찰 결과와 인장시험 후 파면부의 조직변화 관찰 결과로부터 해석되었다. 그 결과 석출상의 형성 여부, 인장 시험 중 재결정 조직의 형성 여부, 라멜라(lamellar) 조직의 분율과 라멜라 간격(lamellar spacing)의 정도 또는 $\beta$-Sn과 라멜라 조직 사이의 결정립계와 라멜라 조직 내 결정립계에서의 슬라이딩 모드(sliding mode) 변형 정도, 석출상의 크기와 분포 정도 등이 연신률 및 변형속도 민감도와 같은 연성 특성에 가장 큰 영향을 미치는 인자인 것으로 분석되었다.

• The korean journal of orthodontics
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• v.34 no.6 s.107
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• pp.473-480
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• 2004

The aim of this study was to establish normative data on the tooth size and arch parameters of Koreans with normal occlusion, This study employed the dental casts of 296 (male: 179; female 117) normal occlusion samples, who were selected from 15,836 adults through a community dental health survey. The mesiodistal diameters of teeth, arch width, and arch length were measured by digital electronic calipers(accurate to 0.01 mm) and Bolton's indices as well as intermaxillary arch width ratios were calculated. In order to ensure reliability, intra- and inter-examiner error were evaluated. Although our dimensional data showed overt differences between genders, the indices and intermaxillary ratios evaluated were the same. The resultant data obtained were compared with the previous data to reveal whether any changes have occurred over the time. The clinical implication of the present findings was also discussed. This biometric study seemed to provide a clinically applicable diagnostic criteria for an individual malocclusion patient.

• Journal of KIISE:Databases
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• v.32 no.3
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• pp.263-275
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• 2005

In a large DNA database, indexing techniques are widely used for rapid approximate sequence searching. However, most indexing techniques require a space larger than original databases, and also suffer from difficulties in seamless integration with DBMS. In this paper, we suggest a space-efficient and disk-based indexing and query processing algorithm for approximate DNA sequence searching, specially exact match queries, wildcard match queries, and k-mismatch queries. Our indexing method places a sliding window at every possible location of a DNA sequence and extracts its signature by considering the occurrence frequency of each nucleotide. It then stores a set of signatures using a multi-dimensional index, such as R*-tree. Especially, by assigning a weight to each position of a window, it prevents signatures from being concentrated around a few spots in index space. Our query processing algorithm converts a query sequence into a multi-dimensional rectangle and searches the index for the signatures overlapped with the rectangle. The experiments with real biological data sets revealed that the proposed method is at least three times, twice, and several orders of magnitude faster than the suffix-tree-based method in exact match, wildcard match, and k- mismatch, respectively.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.07a
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• pp.195-201
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• 2002

입고ㆍ예냉ㆍ출고까지 전 공정을 자동화하고 진공압력을 작물의 품온에 따라 능동적으로 제어할 수 있고 진공챔버내에 콜드트랩을 설치하여 냉각효율을 향상시킨 진공예냉장치를 개발하여 고랭지 배추와 느타리버섯, 상추를 대상으로 예냉성능을 평가하고 예냉이 이들 작물에 미치는 영향을 분석하였다. 가. 새로 개발된 진공식 예냉장치는 공급컨베이어, 좌우 자동 슬라이딩 문, 이송컨베이어, 진공챔버, 진공펌프 콜드트랩, 냉동기로 구성되어 있다. 팔레트를 공급컨베이어에 올려놓고 작동을 시작하면, 입구문이 열리고 팔레트가 진공챔버내로 이송되면, 진공펌프에 의해 진공챔버내의 압력을 떨어뜨리고, 콜드트랩과 냉동기가 작동되어 예냉이 시작된다. 예냉이 완료되면 출구문이 열리고 이송컨베이어가 역회전하여 밖으로 배출되도록 되어있다. 나. 제작된 예냉장치의 예냉성능을 평가하기 위하여 느타리버섯, 고랭지 배추, 상추를 대상으로 냉각속도, 냉각균일도, 예냉후 저장중 품질변화시험을 실시하였다. 다. 시험결과 냉각소요시간은 느타리버섯의 경우 초기품온 15.2$^{\circ}C$에서 $1.5^{\circ}C$까지 냉각시키는데 24분, 고랭지배추는 13.5$^{\circ}C$에서 3.7$^{\circ}C$까지 냉각시키는데 18분, 상추는 13.4$^{\circ}C$에서 2.$0^{\circ}C$까지 냉각시키는데 24분 소요되었다. 평균냉각속도는 느타리버섯이 34.3$^{\circ}C$/h, 고랭지배추 32.6$^{\circ}C$/h, 상추 28.5$^{\circ}C$/h로 나타났다. 라. 또한 각층간의 냉각균일도를 알아보기 위하여 포장상자내에서 표면 품온과 내부품온변화를 조사한 결과 차이가 거의 없어 균일한 냉각이 가능하였다.생기 양단의 온도차는 높게 나타났고, 재생기 양단의 압력 차는 낮게 나타났다. 재생기 축열재로서 철망-철선을 사용할 경우 철선-철망 ø1.2-150이 전열 표면적은 작으나 재생기 양단의 온도차가 가장 큰 것으로 나타났으며 재생기 양단의 압력 차는 가장 낮게 나타나 공시 철망- 철선 혼합 축열재중 가장 우수함을 알 수 있다. 4. 철망사이에 철선을 삽입한 축열재의 경우, 철망사이에 삽입한 철선의 직경이 큰 것이 철선의 직경이 작은 것보다 재생기의 양단의 온도차가 높게 나타났고 재생기 양단의 압력차는 작게 나타났다. 그러므로 철망사이에 철선을 삽입한 것 중 성능이 우수한 것은 150-ø2. 0-150으로 나타났다. 5. 실험한 재생기 축열재들 중에서 성능이 우수한 것들을 비교한 결과, 복합 철선 ø1.2-1 50이 가장 성능이 좋은 것으로 나타났다.적외선.열풍 복합건조방법이 높게 나타나 이것은 곡물 표면에 원적외선 방사에의한 복사열이 전달되어 열장해를 받았기 때문으로 판단되며, 금후 더 연구하여 적정 열풍온도 및 방사체 크기를 구명해야 할 것이다.으로 보여진다 따라서 옻나무 유래 F는 포유동물의 생식기능에 중요하게 작용하는 것으로 사료된다.된다.정량 분석한 결과이다. 시편의 조성은 33.6 at% U, 66.4 at% O의 결과를 얻었다. 산화물 핵연료의 표면 관찰 및 정량 분석 시험시 시편 표면을 전도성 물질로 증착시키지 않고, Silver Paint 에 시편을 접착하는 방법으로도 만족한 시험 결과를 얻을 수 있었다.째, 회복기 중에 일어나는 입자들의 유입은 자기폭풍의 지속시간을 연장시키는 경향을 보이며 큰 자기폭풍일수록 현저했다. 주상에서 관측된 이러한 특성은 서브스톰 확장기 활동이 자기폭풍의 발달과 밀접한 관계가 있음을 시사한다.se that were all low in two aspects, named "the Nonsignificant group". And th

• Journal of KIISE:Databases
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• v.34 no.5
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• pp.409-419
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• 2007

Database community focuses on the similar music retrieval systems for music database when a humming query is given. One of the approaches is converting the midi data to time series, building their indices and performing the similarity search on them. Queries based on humming can be transformed to time series by using the known pitch detection algorithms. The recently suggested algorithm, scaled and warped matching, is based on dynamic time warping and uniform scaling. This paper proposes Humming BIRD(Humming Based sImilaR mini music retrieval system) using sliding window and center-aligned scaled and warped matching. Center-aligned scaled and warped matching is a mixed distance measure of center-aligned uniform scaling and time warping. The newly proposed measure gives tighter lower bound than previous ones which results in reduced search space. The empirical results show the superiority of this algorithm comparing the pruning power while it returns the same results.

• Management & Information Systems Review
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• v.33 no.1
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• pp.45-63
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• 2014

A trading system is a computer trading program that automatically submits trades to an exchange. Mechanical a trading system to execute trade is spreading in the stock market. However, a trading system to trade a single asset might occur instability of the profit because payoff of this system is determined a asset movement. Therefore, it is necessary to develop a trading system that is trade two assets such as a pair trading that is to sell overvalued assets and buy the undervalued ones. The aim of this study is to propose a relative value based trading system designed to yield stable and profitable profits regardless of market conditions. In fact, we propose a procedure for building a trading system that is based on the rough set analysis of indicators derived from a price ratio between two assets. KOSPI 200 index futures and S&P 500 index futures are used as a data for evaluation of the proposed trading system. We intend to examine the usefulness of this model through an empirical study.