• Structural Engineering and Mechanics
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• v.37 no.6
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• pp.671-684
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• 2011

Deciding on an optimal sensor placement (OSP) is a common problem encountered in many engineering applications and is also a critical issue in the construction and implementation of an effective structural health monitoring (SHM) system. The present study focuses with techniques for selecting optimal sensor locations in a sensor network designed to monitor the health condition of Dalian World Trade Building which is the tallest in the northeast of China. Since the number of degree-of-freedom (DOF) of the building structure is too large, multi-modes should be selected to describe the dynamic behavior of a structural system with sufficient accuracy to allow its health state to be determined effectively. However, it's difficult to accurately distinguish the translational and rotational modes for the flexible structures with closely spaced modes by the modal participation mass ratios. In this paper, a new method of the OSP that computing the mode shape matrix in the weak axis of structure by the simplified multi-DOF system was presented based on the equivalent rigidity parameter identification method. The initial sensor assignment was obtained by the QR-factorization of the structural mode shape matrix. Taking the maximum off-diagonal element of the modal assurance criterion (MAC) matrix as a target function, one more sensor was added each time until the maximum off-diagonal element of the MAC reaches the threshold. Considering the economic factors, the final plan of sensor placement was determined. The numerical example demonstrated the feasibility and effectiveness of the proposed scheme.

• Journal of the Korea Safety Management & Science
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• v.14 no.2
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• pp.1-9
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• 2012

As contemporary building construction type is getting higher and deeper, construction equipment usage is getting more, and related fatal accidents are on an increasing trend. Because of this, a method was drawn which could grasp the present state of construction equipment management and manage safety of the equipment more easily for accident prevention by choosing 2 kinds of Construction equipment which cause safety accident frequently among the equipment mainly used in construction site. This study suggested a method about construction equipment safety management using "smart phone" base which could be used in safety management for construction equipment by whomever in construction site. After attachment of QR code included safety checklist, It became possible that site managers could check more efficiently by scanning with their smart phone when they inspect equipment. Moreover, by the construction interested who didn't know what and how they have to inspect could point out unsafe condition in the early stage of equipment entering or take unsafe one out of the site by using new smart phone safety checking system is installed, it became possible that critical accident caused by construction equipment was prevented in advance.

• Proceedings of the Safety Management and Science Conference
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• 2012.04a
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• pp.43-59
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• 2012

As contemporary building construction type is getting higher and deeper,construction equipment usage is getting more, and related fatal accidents are on an increasing trend. In these days, due to the deteriorating construction business circumstance, job finding problem of equipment operator, and dumping contract, equipment lease suppliers are putin jeopardy. In high-rise building construction, especially tower crane, mobile elevated work platform and other High place operation cars among construction equipment cause many critical accidents because of drop supply of construction biding bringing out dumping contract could cause unsafe and poor construction management. Because of this, a method was drawn which could grasp the present state of construction equipment management and manage safety of the equipment more easily for accident prevention by choosing 2 kinds of Construction equipment which cause safety accident frequently among the equipment mainly used in construction site. This study suggested a method about construction equipment safety management using "smart phone" base which could be used in safety management for construction equipment by whomever in construction site. After attachment of QR code included safety checklist, It became possible that site managers could check more efficiently by scanning with their smart phone when they inspect equipment. Moreover, by the construction interested who didn't know what and how they have to inspect could point out unsafe condition in the early stage of equipment entering or take unsafe one out of the site by using new smart phone safety checking system is installed, it became possible that critical accident caused by construction equipment was prevented in advance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.135-140
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• 2013

With the advent of smart phones recently, users have experienced a new way of communicating using a smart phone without the constraints of time and space. As a result, users are ubiquitous around the user's own resources and a variety of natural interaction that was required. In particular, the interaction between the user and the content in the virtual reality and augmented reality, otherwise your content or service in the real world and the virtual direct and intuitive interaction can be. In this paper, we use Augmented Reality smart-phone sitting in the subway system that allows people to know the arrival station is designed to offer.

• Human Ecology Research
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• v.54 no.3
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• pp.333-349
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• 2016

This study develops and evaluates a game-based lesson plan applied to the 'Food Culture' unit of a high school Home Economics class. We developed, implemented, and evaluated lesson plans for seven periods that contained 'the Korean food table setting card,' 'the world's food culture card,' and the procedure for cards games according to the Analysis, Design, Development, Implementation, and Evaluation (ADDIE) model. 'The Korean food table setting card' consisted of 'the Korean food table setting order card' to easily understand 10 types of Korean traditional daily meals based on pictures and 'the Korean food table setting food card' to easily understand Korean traditional food based on 104 kinds of food picture and quick response (QR) code. 'The world's food culture card' consisted of 'the world's food culture quiz card' to help learners easily understand influential food culture formation factors, features of food culture, typical foods from 16 countries, and 'the world's traditional food card' to help learners easily understand typical foods from 16 countries through 63 kinds of pictures. Respective 'game guides' were also developed. High school students who studied the game-based Home Economics classes and who participated in the 'Food Culture' unit, could easily and enjoyably learn the food culture of Korea (and other countries), actively participate in learning activities, and understood the content of food culture. In addition, they evaluated that the game-based instruction was easy to remember with minimal memorizing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.2072-2079
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• 1998

In this paper, we propose a new decorrelating detector called pseudo-inverse-filtering type decorrelating detector for asynchronous CDMA channels. We first show that the matched filtering and decorrelating operations of the existing decorrelating detectors can be replaced with the pseudo-inverse filtering operations in synchronous channels, and using this fact we show that the decorrelating detector has the largest SNR among the linear detectors that can eliminate MAI. Then we introduce asynchronous pseudo-inverse filtering type decorrelating detector by extending this result for asynchronous channels, and discuss implementation methods of the proposed decorrelating detectors. Since the proposed scheme employs a decentralized structure for updating coefficients, it has the flexibility to add/remove users. Finally we analyze the performance of the proposed decorrelating detector in terms of the bit error rate, and examine its performance improvements over the conventional detectors through computer simulations.

• Journal of the Korea Society of Computer and Information
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• v.17 no.6
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• pp.119-130
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• 2012

In this paper, we propose ubiquitous tree management system based on GIS and smart-phone using the object-oriented design modeling to maximize the efficiency of tree management. For this, proposed system is implemented in the form of client/server (C/S). The spot tree management system as the client is based on the mobile(PDA, Smart-Phone), whereas the tree management system based on PC as the server makes use of GIS. Also, Web service method instead of CDMA used in exist studies is used for tree data communication among C/S. And problems of existing studies, that is excessive maintenance costs, accessibility shortage of variety users, connectivity shortage of geographic information system will be settled through the convergence of the proposed system development methods, GIS system, smart devices. Therefore, we verify proposed system by using the systemic unit test and qualitative assessment respectively and prove to be more excellent than the existing system based on the mobile, in terms of systemic effectiveness and extendability.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.6
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• pp.539-546
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• 1999

A new integrated single-stage zero current switched(ZCS) quasi resonant convertedQRC) for the IX)wer f factor correction(PFCl converter is introduced in this paper. The power factor correction can be achieved by t the discontinuous conduction mod$\varepsilon$(DCM) operation of an input current. The proposed converter has the c characteristics of the good IX)wer factor, 10씨 line current harmonics, and tight output regulation. Furthern10re, t the ringing effect due to the output capacitance of the main switch can be eliminated by use of‘ active clamp c circuit. Therefore, the proIX)sed converter is expecttc'(] to be suitable for a compact power converter with a t tightly regulated output voltage requiring a switching frequency of more than several hundrtc'(]s kHz.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.443-443
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• 2012

최근 지구 온난화 및 기후변화로 인하여 국지적 집중호우에 의한 농지 침수 및 유실 피해가 점차 증가 추세에 있으며 가뭄에 의한 물 부족 현상도 심화되고 있다. 이와 같은 홍수 및 가뭄 피해에 대비하기 위하여 농업용 저수지와 수문 그리고 농수로와 같은 농업수리시설물이 신축 운영되고 있으나 이들 시설물은 비교적 규모가 작은 대신에 그 수가 매우 많고 또한 지역적으로 널리 산재해 있기 때문에 관리자가 이들을 효율적으로 운영하고 관리하는데 한계가 있다는 특징이 있다. 더욱이 이들 시설물은 물과 항상 접하는 철근 콘크리트 구조물로 이루어져 있어서 시간이 경과함에 따라 균열발생과 철근부식과 같은 노후화 현상이 뚜렷하게 진전되어 정기적 안전점검이 필요한 실정이다. 이에 따라 농업수리시설을 보다 체계적으로 관리하고 농업용수를 보다 효율적으로 확보 운영하기 위하여 물관리 자동화 사업이 추진되어 많은 개선이 이루어졌으나 아직까지 현장업무가 관리자의 수작업에 의존하고 있으며 농촌 용수의 정확한 정보가 제때에 제공되지 못하는 등 농업수리시설에 대한 다양한 요구를 충족시키지 못하고 있다. 따라서, 농촌수자원의 효율적 관리를 위하여 농업수리시설 가운데 하나인 농수로의 수위 및 유량 정보를 자동으로 측정하며 농업수리시설물의 상태 정보를 입력하고 관리할 수 있는 모바일 App을 개발하였다. 안드로이드 OS 기반의 스마트폰을 활용하였으며 여기에는 시설물 고유정보가 포함된 QR코드 및 Active 태그를 통하여 시설물의 상태정보를 원격에 있는 서버 컴퓨터로 전송할 수 있는 원거리 무선통신 모듈이 구비되어 있다. 특히, 농업수리시설물 관리 어플리케이션은 현장관리자가 기존에 수기방식으로 시설물을 관리해 오던 것을 휴대단말 상에서 보다 효율적으로 관리를 함으로써 시설물 유지관리 업무의 효율성을 향상시키는 특징이 있다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.2
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• pp.117-126
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• 2019

Legacy study for detecting arrhythmia have mostly used nonlinear method to increase classification accuracy. Most methods are complex to process and manipulate data and have difficulties in classifying various arrhythmias. Therefore it is necessary to classify various arrhythmia based on short-term data. In this study, we propose a feature extraction based on auto regressive modeling and an premature contraction arrhythmia classification method using SVM., For this purpose, the R-wave is detected in the ECG signal from which noise has been removed, QRS and RR interval segment is modelled. Also, we classified Normal, PVC, PAC through SVM in realtime by extracting four optimal segment length and AR order. The detection and classification rate of R wave and PVC is evaluated through MIT-BIH arrhythmia database. The performance results indicate the average of 99.77% in R wave detection and 99.23%, 97.28%, 96.62% in Normal, PVC, PAC classification.