• 한국정보처리학회논문지
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• 제3권5호
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• pp.1198-1206
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• 1996

본 논문에서는 무궁화 위성을 통하여 구축하게 될 DAMA-SCPC Ground Systen-200 (DGS-200) 방식을 이용한 위성 통신망의 중앙제어국에서 수행되는 통신망 관리기능을 제시한다. 그리고 효율적인 통신망 운용 관리를 위하여 통신망 구성 요소를 계층 구조 적으로 분류하여, 나무 구조를 갖는 그래픽 객체 구성 요소들을 제시한다. 그리고 이 논문에서는 실시간 통신망 관리 시스템을 구현하기 위한 그래픽 객체 표현 방법을 제시하고 클라이언트/서버로 구성된 실시간 통신망 관리 알고리즘을 제안한다. 제시된 방법들은 컴퓨터 시뮬레이션을 통하여 제안한 알고리즘의 성능을 확인하였다.

• 한국통신학회논문지
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• 제31권5C호
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• pp.540-547
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• 2006

본 논문에서는 900 MHz RFID 표준 프로토콜 중 하나인 ISO/IEC 18000-6 type B 프로토콜의 충돌방지 알고리즘의 성능을 분석하고, 이에 대한 성능 향상 방법을 제안한다. 제안된 방법은 ISO/IEC 18000-6 type B 프로토콜의 충돌방지 알고리즘에서 명령 전송 횟수 및 전송 데이터의 양을 줄임으로써 태그 인식 속도를 개선한다. 시뮬레이션 결과를 통해 제안된 방법이 리더 인식 영역 내의 태그 개수와 관계없이 태그 인식 속도를 기존 방법에 비해 21.7% 향상시킬 수 있음을 보인다.

• 제어로봇시스템학회논문지
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• 제20권9호
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• pp.957-963
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• 2014

This paper proposes a predictive control for an efficient human following robot using Kinect sensor. Especially, this research is focused on detecting of foot-end-point and foot-vector instead of human body which can be occluded easily by the obstacles. Recognition of the foot-end-point by the Kinect sensor is reliable since the two feet images can be utilized, which increases the detection possibility of the human motion. Depth image features and a decision tree have been utilized to estimate the foot end-point precisely. A tracking point average algorithm is also adopted in this research to estimate the location of foot accurately. Using the continuous locations of foot, the human motion trajectory is estimated to guide the mobile robot along a smooth path to the human. It is verified through the experiments that detecting foot-end-point is more reliable and efficient than detecting the human body. Finally, the tracking performance of the mobile robot is demonstrated with a human motion along an 'L' shape course.

• ETRI Journal
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• 제22권3호
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• pp.41-51
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• 2000

An important use of data warehousing is to provide temporal views over the history of source data. It is significant that nearly all data warehouses are dependent on relational database technology, yet relational databases provide little or no real support for temporal data. Therefore, in is difficult to obtain accurate information for time-varying data. In this paper, we are going to design a temporal data warehouse to support time-varying data efficiently. For this purpose, we present a method to support temporal query by combining a temporal query process layer with the relational database which is used as a source database in an existing data warehouse. We introduce the Temporal Aggregate Tree Strategy (TATS), and suggest its algorithm for the way to aggregate the time-varying data that is changed by the time when the temporal view is created. In addition, The TATS and the materialized view creation method of the existing data warehouse have been evaluated. As a result, the TATS reduces the size of the fact table and it shows a good performance for the comparison factor in case of processing the query for time-varying data.

• 천문학회보
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• 제37권1호
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• pp.39.2-39.2
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• 2012

We present our study on a comparison of dark matter halo merger history from the runs using different numerical simulation codes. To analyze the uncertainty caused by the use of different N-body calculation methods, we compare the results from two cosmological hydrodynamic simulation codes GADGET-2 and RAMSES, which use a TreePM algorithm and the Adaptive Mesh Refinement(AMR) technique respectively. We perform cosmological dark matter-only simulations with the same parameter set and initial condition for both. The dark matter halo mass functions from two simulation runs correspond well with each other, except for lower mass haloes. The discrepancy on the low-mass haloes in turn causes a notable difference in halo merger rate, especially for the case of extremely minor merger. The result from GADGET-2 predicts that most haloes undergo more number of mergers with small haloes than that from RAMSES, independent of halo mass and environment. However, in the context of the study on galaxy evolution, such extreme minor mergers generally do not have strong effects on galaxy properties such as morphology or star formation history. Hence, we suggest that this uncertainty could be quantitatively negligible, and the results from two simulations are reliable even with only minor difference in merger history.

• 한국생산제조학회지
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• 제21권5호
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• pp.720-725
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• 2012

Sodium hypochlorite is used worldwide as a water disinfectant and in bleaching agent. Sodium hypochlorite applied to water initially undergoes hydrolysis to form free chlorine consisting of hypochlorous acid(HOCl) and hypochlorite ion($OCl^-$). For free chlorine determination, an electrochemical method is simple due to the electroactivity of free chlorine; it measures current and is free of most reagents. Amperometric free chlorine sensor has been developed with gold (Au)-based electrode. The 3-electrode free chlorine sensor whose working and counter electrodes were Pt exhibited excellent response to HClO at +400mV vs. Ag/AgCl/sat. KCl. In addition, the use of a pH error correction algorithm provided a reliable measurement of residual free chlorine in water sample without any pretreatment in the normal pH range(pH 6~8) of municipal water supply. The free chlorine sensor installed in on-line monitoring system could be used to continually monitor the level of residual free chlorine in real samples.

• 정보기술응용연구
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• 제3권2호
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• pp.1-24
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• 2001

본 연구는 R사의 대고객 만족도 향상을 위하여 고객관계관리(customer relationship management, CRM)를 수행하기 위한 목적으로 추진되었다. 연구의 주안점은 연구관리 데이터베이스로부터 연구관련 변수들의 패턴 및 상호작용을 고려하여 연구계약기관을 기관별 연 구과제의 연구유형 및 연구비에 대한 분석을 통하여 고객유형별로 분류함으로써 향후 대고객관리의 방향을 설정하기 위한 목적으로 시도되었다. 본 연구에서 의사결정나무 알고리듬을 이용하여 자료를 분석한 결과, 17개의 입력변수 중 내외부 계약기관을 분류하는 데 있어서 중요한 변수로는 연구기간, 제경비, 기술개발비의 3개 변수로 나타났다. 연구결과, R사의 고객은 6개월 이상의 연구기간, 3,000만원 이상의 제경비, 그리고 6,075만원의 기술개발비를 기준으로 연구계약기관이 분류되며, 이 연구관련 변수를 이용하여 대고객과의 연구주제 설정, 연구예산 수립 등의 고객관리방안을 수립할 수 있을 것이다.

• 전기전자학회논문지
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• 제11권4호
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• pp.322-330
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• 2007

Recent advances in wireless networks and low-cost, low-power design have led to active research in large-scale networks of small, wireless, low power sensors and actuators, In large-scale networks, lots of timing-synchronization protocols already exist (such as NTP, GPS), In ad-hoc networks, especially wireless sensor networks, it is hard to synchronize all nodes in networks because it has no infrastructure. In addition, sensor nodes have low-power CPU (it cannot perform the complex computation), low batteries, and even they have to have active and inactive section by periods. Therefore, new approach to time synchronization is needed for wireless sensor networks, In this paper, I propose Energy-Efficient Time Synchronization (EETS) protocol providing network-wide time synchronization in wireless sensor networks, The algorithm is organized two phase, In first phase, I make a hierarchical tree with sensor nodes by broadcasting "Level Discovery" packet. In second phase, I synchronize them by exchanging time stamp packets, And I also consider send time, access time and propagation time. I have shown the performance of EETS comparing Timing-sync Protocol for Sensor Networks (TPSN) and Reference Broadcast Synchronization (RBS) about energy efficiency and time synchronization accuracy using NESLsim.

• 제어로봇시스템학회논문지
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• 제21권10호
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• pp.958-964
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• 2015

In this paper, an object recognition method based on the depth information from the RGB-D camera, Xtion, is proposed for an indoor mobile robot. First, the RANdom SAmple Consensus (RANSAC) algorithm is applied to the point cloud obtained from the RGB-D camera to detect and remove the floor points. Next, the removed point cloud is classified by the k-means clustering method as each object's point cloud, and the normal vector of each point is obtained by using the k-d tree search. The obtained normal vectors are classified by the trained multi-layer perceptron as 18 classes and used as features for object recognition. To distinguish an object from another object, the similarity between them is measured by using Levenshtein distance. To verify the effectiveness and feasibility of the proposed object recognition method, the experiments are carried out with several similar boxes.

• 한국작물학회지
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• 제54권3호
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• pp.332-338
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• 2009

Rapid extension of genomic database leads to the remarkable advance of functional genomics. This study proposes a novel methodology of functional analysis using 5-methyltrytophan (5 MT) mutant together with their 2-DE analysis and public microarray database. A total of 24 proteins was changed in 5 MT mutant and four remarkably different expressed proteins were identified. Among them, three spots were converted to Affymetrix probe. A total of 155 microarray samples from Gene Expression Omnibus (GEO) in NCBI was retrieved and followed by constructing gene co-expression networks over a broad range of biological issues through Self-Organising Tree Algorithm. Three co-expressing gene clusters were retrieved and each functional categorization with differential expression pattern was exhibited from 5 MT resistance mutant rice. It was indicated new co-expression networks in the mutant. This study suggests that on investigating possibility which correspond 2-DE to microarray database with their full potential.