• Journal of KIISE:Databases
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• v.36 no.3
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• pp.198-214
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• 2009

Trajectories of RFID tags can be modeled as a line, denoted by tag interval, captured by an RFID reader and indexed in a three-dimensional domain, with the axes being the tag identifier (TID), the location identifier (LID), and the time (TIME). Distribution of tag intervals in the domain space is an important factor for efficient processing of a query for tracing tags and is changed according to arranging coordinates of each domain. Particularly, the arrangement of LIDs in the domain has an effect on the performance of queries retrieving the traces of tags as times goes by because it provides the location information of tags. Therefore, it is necessary to determine the optimal ordering of LIDs in order to perform queries efficiently for retrieving tag intervals from the index. To do this, we propose LID proximity for reordering previously assigned LIDs to new LIDs and define the LID proximity function for storing tag intervals accessed together closely in index nodes when a query is processed. To determine the sequence of LIDs in the domain, we also propose a reordering scheme of LIDs based on LID proximity. Our experiments show that the proposed reordering scheme considerably improves the performance of Queries for tracing tag locations comparing with the previous method of assigning LIDs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.447-454
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• 2011

Power-line interference(PLI) can distort certain regions in analysing the ECG signal. In particular, the regions such as P and R wave that are important element in diagnosing with arrhythmia is expressed as different type of noise according to the case whether power-line frequency is multiples of sampling frequency and or not. Noise characteristics is also divided into linearity and non-linearity. In this paper, adaptive subtraction method for removing variable PLI of ECG signal is proposed. We classify the multiple relationship between power line and sampling frequency as Multiple and Non-multiple. PLI of Linear segment is extracted through moving average filter, PLI of non-linear segment is extracted through the interference component that is extracted in the linear segment and stored in the temporary buffer. The performance of P wave and R wave detection is evaluated by using 119 data record of MIT-BIH arrhythmia database. The achieved scores indicate P wave detection rate of 97.91%, R wave detection rate of 96.66% and P wave detection rate of 99.01%, R wave detection rate of 97.93% accuracy respectively for Notch filter and proposed subtraction method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.3807-3818
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• 2015

The objective of this study is to develop an on-line system for improving undergraduate students' competency development. After drawing elements necessary for the competency development such as assessment and planning, competency development, analysis of competency assessment, portfolio, analysis of job ability and community, based on the literature research related to competency and the analysis of the existing system, the direction of the system design was set up. The system was developed by using Microsoft Windows operating system in Windows server, ORACLE ver.10 as its database management system, and JSP and JAVA as its programing language. Reviewing errors and improvements of the system, it was modified and complemented. In order to examine the content functional utilization of the final competency development system, the utilization was verified. The competency development system for undergraduate students can be used as on-line space filled with the internalization of knowledge, self-directed competency development, convenience of record management and interactions between students-professors-alumna, owing to its functions such as boosting competency activities, cultivating career-pioneering ability and introspecting. When it is rare to find researches on the competency development system for undergraduate students, it is expected to be helpful to the development of competency education and the career education for undergraduate students as a new alternative for the competency development.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.58-60
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• 2004

웹의 확산과 더불어 웹 페이지 검색의 성능 즉, 빠른 응답시간과 확장성(scalability)은 각 웹 사이트의 절대적 평가 기준이 되었다. 웹 옹용은 일반적으로 불특정 다수를 대상으로 하기 때문에 확장성 또한 주요 성능의 척도가 된다. 이와 같은 웹 사이트 성능을 담보하기 위한 대표적 요소기술이 웹 캐슁이다. 본 논문은 웹 상에서 XML 데이터베이스 기반의 웹 응용(XML database-backed web application)을 위한 응용서버의 XML 캐쉬를 이용하여 주어진 XML 질의를 변환, 처리하는 기법과 구현에 관한 것으로 XPath의 경로표현식 중 가장 중요한 세 가지 기능인 조건을 명시하는 필터 연산자, 부모-자식 관계를 나타내는 경로 연산자(/), 그리고 조상-후손 관계를 나타내는 경로 연산자(//)를 연구 범위로 하였다. [2]에서는 조상-후손 관계를 나타내는 경로 연산자(//)가 없는 경우에 경로표현식으로 주어진 XML 질의를 캐쉬를 이용하여 변환, 처리하는 알고리즘을 제시하였는데 본 논문에서는 [2]의 알고리즘을 확장하여 경로 연간자(//)가 지원되도록 하였다. 조상-후손 경로 연산자(//)로는 정규경로 표현식(regular path expression)을 나타낼 수 있는데 이는 스키마가 불확실한 반구조적 데이터인 XML 데이터에 대한 질의 표현에 유용하다. 제시된 알고리즘에서는 DTD를 이용하여 경로 정보를 얻어 처리함으로써 주어진 질의를 캐쉬와 하부 XML 소스에 대한 질의로 변환하였다. 이 알고리즘을 바탕으로 관계 DBMS를 이용하여 구현된 시스템으로 실제 웹 상에서 성능 실험을 수행하였다. 성능 실험 결과 정규 경로 표현식을 포함하는 XML 질의에 대해서도 웹에서 캐쉬를 이용한 처리가 효율적임을 확인하였다.키는데 목적이 있다.RED에 비해 향상된 성능을 보여주었다.웍스 네트워크상의 다양한 디바이스들간의 네트워크 다양화와 분산화 기능을 얻을 수 있었고, 기존의 고가의 해외 솔루션인 Echelon사의 LonMaker 소프트웨어를 사용하지 않고도 국내의 순수 솔루션인 리눅스 기반의 LonWare 3.0 다중 바인딩 기능을 통해 저 비용으로 홈 네트워크 구성 관리 서버 시스템 개발에 대한 비용을 줄일 수 있다. 기대된다.e 함량이 대체로 높게 나타났다. 점미가 수가용성분에서 goucose대비 용출함량이 고르게 나타나는 경향을 보였고 흑미는 알칼리가용분에서 glucose가 상당량(0.68%) 포함되고 있음을 보여주었고 arabinose(0.68%), xylose(0.05%)도 다른 종류에 비해서 다량 함유한 것으로 나타났다. 흑미는 총식이섬유 함량이 높고 pectic substances, hemicellulose, uronic acid 함량이 높아서 콜레스테롤 저하 등의 효과가 기대되며 고섬유식품으로서 조리 특성 연구가 필요한 것으로 사료된다.리하였다. 얻어진 소견(所見)은 다음과 같았다. 1. 모년령(母年齡), 임신회수(姙娠回數), 임신기간(姙娠其間), 출산시체중등(出産時體重等)의 제요인(諸要因)은 주산기사망(周産基死亡)에 대(對)하여 통계적(統計的)으로 유의(有意)한 영향을 미치고 있어 $25{\sim}29$세(歲)의 연령군에서, 2번째 임신과 2번째의 출산에서 그리고 만삭의 임신 기간에, 출산시체중(出産時體重) $3.50{\sim}3.99kg$사이의 아이에서 그 주산기사망률(周産基死亡率)이 각각 가장 낮았다. 2. 사산(死産)과 초생아사망(初生兒死亡)을 구분(區分)하여 고려해 볼때 사산(死産)은 모성(母性)의 임신력(

• Korean Journal of Psychosomatic Medicine
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• v.30 no.1
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• pp.7-15
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• 2022

Objectives : The purpose of this study is to identify the effect of office workers' stress level and stress vulnerability on heart rate variability (HRV), confirm the significance of objective stress indicators obtained through subjective stress and heart rate variability devices, and examine their effectiveness as an integrated stress measurement tool in community mental health projects. Methods : From June to July in 2020, 929 workers participated in the stress management and mental health promotion project carried out by K hospital, and their recorded database was used for study analysis with their agreements. Multiple linear regression analysis was performed to find out the effects of general stress level, and stress vulnerability on heart rate variability. Results : All general characteristics were found to have a significant effect on SDNN (ln), RMSSD (ln), LF (ln), and HF (ln), but work experience did not significantly affect RMSSD (ln). Stress level and stress vulnerability did not significantly affect heart rate variability, but stress perception, a sub-factor of stress level, was found to have a significant effect on RMSSD (ln) (β=0.118, p=0.023). Conclusions : In this study, stress perception, a sub-factor of stress level, was found to be a factor affecting RMSSD (ln). This indicates an association with the activity of parasympathetic nerves in stressful situations, and more follow-up studies are needed to use it as a direct indicator of chronic stress and integrated stress in the community mental health field.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3B
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• pp.301-310
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• 2006

Typically, we needs enormous national budget for the flood control project and so the project usually has big influence on the national economy. Therefore, the reliable estimation of flood damage is the key issue for the economic analysis of the flood control project. This study aims to provide a GIS based technique for distributed flood damage estimation. We consider two aspects of engineering and economic sides, which are the inundation analysis and MD-FDA (Multi-Dimensional Flood Damage Analysis), for the flood damage assessment. We propose the analysis framework and data processing using GIS for assessing flood damages. The proposed methodology is applied to the flood control channel project for flood disaster prevention in Mokgamcheon/Dorimcheon streams and this study presents the detailed GIS database and the assessment results of flood damages. This study may have the worth in improving practical usability of MD-FDA and also providing research direction for combining economic side with the engineering aspect. Also this distributed technique will help decision-making in evaluating the feasibility of flood damage reduction programs for structural and nonstructural measures.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.1
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• pp.39-58
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• 2024

Tunnel Boring Machines (TBM) use multiple disc cutters to excavate tunnels through rock. These cutters wear out due to continuous contact and friction with the rock, leading to decreased cutting efficiency and reduced excavation performance. The rock's abrasivity significantly affects cutter wear, with highly abrasive rocks causing more wear and reducing the cutter's lifespan. The Cerchar Abrasivity Index (CAI) is a key indicator for assessing rock abrasivity, essential for predicting disc cutter life and performance. This study aims to develop a new method for effectively estimating CAI using rock strength, petrological characteristics, linear regression, and machine learning. A database including CAI, uniaxial compressive strength, Brazilian tensile strength, and equivalent quartz content was created, with additional derived variables. Variables for multiple linear regression were selected considering statistical significance and multicollinearity, while machine learning model inputs were chosen based on variable importance. Among the machine learning prediction models, the Gradient Boosting model showed the highest predictive performance. Finally, the predictive performance of the multiple linear regression analysis and the Gradient Boosting model derived in this study were compared with the CAI prediction models of previous studies to validate the results of this research.

• Journal of Korea Spatial Information System Society
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• v.6 no.1 s.11
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• pp.73-85
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• 2004

Recently, as the growth of the wireless Internet, PDA and HPC, the focus of research and development related with GIS(Geographic Information System) has been changed to the Real-Time Mobile GIS to service LBS. To offer LBS efficiently, there must be the Real-Time GIS platform that can deal with dynamic status of moving objects and a location index which can deal with the characteristics of location data. Location data can use the same data type(e.g., point) of GIS, but the management of location data is very different. Therefore, in this paper, we studied the Real-Time Mobile GIS using the HBR-tree to manage mass of location data efficiently. The Real-Time Mobile GIS which is developed in this paper consists of the HBR-tree and the Real-Time GIS Platform HBR-tree. we proposed in this paper, is a combined index type of the R-tree and the spatial hash Although location data are updated frequently, update operations are done within the same hash table in the HBR-tree, so it costs less than other tree-based indexes Since the HBR-tree uses the same search mechanism of the R-tree, it is possible to search location data quickly. The Real-Time GIS platform consists of a Real-Time GIS engine that is extended from a main memory database system. a middleware which can transfer spatial, aspatial data to clients and receive location data from clients, and a mobile client which operates on the mobile devices. Especially, this paper described the performance evaluation conducted with practical tests if the HBR-tree and the Real-Time GIS engine respectively.

• Korean Journal of Clinical Pharmacy
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• v.16 no.2
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• pp.86-91
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• 2006

There are 3 different hypotheses on how statins may affect bones, through promoting bone formation, inhibiting bone resorption or through anti-inflammatory effect. In the 3 cross-sectional studies above, one showed increase BMD at hip and spine, one showed increase BMD only at mid-forearm and one showed that the risk reduction in fractures is not explained by the changes in BMD however, all 3 studies showed a decrease in risk of fracture associated with statins. In the 2 prospective cohort studies, one showed the use of statins was not associated with BMD at any skeletal site or decreasing the risk of fracture, and the other showed statins except pravastatin decreased in risk of vertebrate fracture but not affecting lumbar spine BMD. All of case-control studies indicated reduction in fracture risk but did not provide any data regarding BMD. 2 of the randomized, controlled studies showed no significant reduction in fracture risk as well as statins' effects on BMD. Finally, one longitudinal study showed statin use reduced fracture risk and increased BMD. Among the conflicting results shown above, even when statin use was shown to increase BMD, it does not seem to account for the reduction in fracture risk. There may be different ways that statins affect bone other than those hypotheses proposed above. Many studies seem to agree that pravastatin does not have any effect on bone. Some studies suggested that the reason statins did not achieve clinically significant increases in BMD in some studies, is due to the low affinity of statins on bone; statins are designed to act in the liver therefore their effective concentration in extrahepatic tissue is low. The limitations to those studies discussed above. Many studies did not account for the change of lifestyle while subjects' were on statins. Increases in weight bearing exercise and changes in diet might affect BMD and thus reduce risk of fractures. Mental alertness and vision acuity might prevent falls from occurring; many statin-users in the studies were young so the risk of fractures from falls would be decreased. Almost all of the studies failed exclude patients with neurological problems. During study periods, many subjects may have been started on drugs for diseases that usually occur with aging which could cause drowsiness and lead to falls. The sample sizes used in some of the trials were small and the duration of treatment and follow up might not have been long enough to see clinically relevant results.

• Journal of Korea Spatial Information System Society
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• v.5 no.1 s.9
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• pp.49-63
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• 2003

Recently, two international standard organizations, ISO and OGC, have done the work of standardization for GIS. Current standardization work for providing interoperability among GIS DB focuses on the design of open interfaces. But, this work has not considered procedures and methods for designing GIS DB. Eventually, GIS DB has its own model. When we share the data by open interface among heterogeneous GIS DB, differences between models result in the loss of information. Our aim in this paper is to revise the design guidelines for geographic information databases in order to make consistent spatial data models, logical structures, and semantic structure of populated geographical databases. In details, we propose standard guidelines which convert ISO abstract schema into relation model, object-relation model, object-centered model, and geometry-centered model. Furthermore, we provide sample models for applying these guidelines in commercial GIS S/Ws. Building GIS DB based on design guidelines proposed in the paper has the following advantages: the interoperability among databases, the standardization of schema definitions, and the catalogue of GIS databases through.