• International journal of advanced smart convergence
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• 제7권3호
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• pp.23-36
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• 2018

In wireless communication, efficient spectrum usage is an issue that has been an attractive research area for many technologies. Recently new technologies innovations allow compact radios to transmit with power efficient communication over very long distances. For example, Low-Power Wide Area Networks (LPWANs) are an attractive emerging platform to connect the Internet-of-Things (IoT). Especially, LoRa is one of LPWAN technologies and considered as an infrastructure solution for IoT. End-devices use LoRa protocol across a single wireless hop to communicate to gateway(s) connected to the internet which acts as a bridge and relays message between these LoRa end-devices to a central network server. The use of the (ISM) spectrum sharing for such long-range networking motivates us to implement spectrum sensing testbed for cognitive radio network based on LoRa and GNU radio. In cognitive radio (CR), secondary users (SUs) are able to sense and use this information to opportunistically access the licensed spectrum band in absence of the primary users (PUs). In general, PUs have not been very receptive of the idea of opportunistic spectrum sharing. That is, CR will harmfully interfere with operations of PUs. Subsequently, there is a need for experimenting with different techniques in a real system. In this paper, we implemented spectrum sensing for cognitive radio networks based on LoRa and GNU Radio, and further analyzed corresponding performances of the implemented systems. The implementation is done using Microchip LoRa evolution kits, USRPs, and GNU radio.

• 한국환경생태학회지
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• 제21권1호
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• pp.13-21
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• 2007

본 연구는 국립공원 탐방로 시설물 설치와 유지관리 개선 방안 마련을 위한 기초 연구로서 소백산국립공원 희방사$\sim$연화봉 구간 탐방로를 이용한 탐방객과 전문가의 보행시설에 대한 평가를 목적으로 실시하였다. 이를 위해 대상지를 방문하고 귀가하는 탐방객(125명)과 전문가 패널(12명)을 대상으로 응답자 직접기입 방식을 적용하여 설문조사를 실시하였다. 연구결과 연구대상지 보행시설물 6개 유형에 대한 탐방객과 전문가의 감응성 차이가 분명하게 나타났으며 돌깔기와 목재데크는 3개 속성 모두 비교적 우수한 시설물로 평가되었다. 철교량과 철계단의 경우 자원보전 효과는 있으나 주변과의 경관조화성이 떨어져 특히 개선이 요구되는 시설로 평가되었다.

• 한국CDE학회논문집
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• 제19권4호
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• pp.347-355
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• 2014

IFC converters and viewers, applicable in the construction field, are being actively developed while, in the civil engineering field, IFC schemata are being developed. To prove the IFC schema grammatically, the existing ISO 10303 30s' pre-processors and post-processors may be used. However, to visually prove the IFC model, the existing commercial 3D modeling software should be converted into the IFC schema of civil engineering field, and a viewer is needed to view it. Thus, this study developed a IFC converter and viewer prototype system to apply BIM in the road field. To express the road line, LandXML was analyzed, and IFC suitable for expressing shapes in the road field was designed. Also, an IFC suitable for bridges with focus on representative bridge structures such as abuts, piers and decks was designed. Further, a converter was developed using AutoCAD's Civil3D and Revit's 3rdp party tools, and software was also developed designed to combine each converted IFC model into one IFC. In addition, a viewer designed to view IFC in the road field was developed to prove the converted IFC. Eight major verification and examination items were selected and used in testing the converted model, and it was confirmed that the viewer normally viewed the IFC schema in the road field. The proposed IFC converter is expected to be used as a visual IFC verification tool in the road field.

• 대한지리학회지
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• 제42권2호
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• pp.295-313
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• 2007

지리학은 오랫동안 자연과학과 인문과학을 연결하는 역할을 수행해왔기에 학문 간의 통합적 시각으로서의 특징을 갖는다고 할 수 있다. 본 연구는 이러한 지리학의 통합학문으로서의 역할에 기초하여 환경교육에 접근하는 통합교육과정의 효과를 먼저 고찰하고자 한다. 이를 바탕으로, "에잇틴마일 크릭의 환경 연구"라는 제목으로 8학년을 위한 일곱 차례의 90분간 수업을 위한 수업 안을 구성하였다. GIS는 자녀교육을 보다 학습자 중심의 교육으로, 보다 적극적인 학습이 이루어지게 하고, 또한 우리가 살고 있는 삶을 중심으로 하여 실생활과 밀접한 학습이 가능하도록 하는 중요한 역할을 감당할 것으로 기대되며, 이를 통해 지리학을 중심으로 하는 다학문간의 통합적 시각을 강화하고 활성화할 것이다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.117-129
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• 2009

This paper studied the safety management network system of infrastructure which constructed smart sensors, closed-circuit television(CCTV) and monitoring system. This safety management of infrastructure applied to bridge, cut slop and tunnel, embankment etc. The system applied to technologies of standardization guidelines, data acquirement technologies, data analysis and judgment technologies, system integration setup technology, and IT technologies. It was constructed safety management network system of various infrastructure to improve efficient management and operation for many infrastructure. Integrated safety management network system of infrastructure consisted of the real-time structural health monitoring system of each infrastructure, integrated control center, measured data transmission using i of tet web-based, collecting data using sf ver, early alarm system which the dangerous event of infrastructure occurred. Integrated control center consisted of conference room, control room to manage and analysis the data, server room to present the measured data and to collect the raw data. Early alarm system proposed realization of warning and response within 5 minute or less through development of sensor-based progress report and propagation automation system using the media such as MMS, VMS, EMS, FMS, SMS and web services of report and propagation. Based on this, the most effective u-Infrastructure Safety Management System is expected to be stably established at a less cost, thus making people's life more comfortable. Information obtained from such systems could be useful for maintenance or structural safety evaluation of existing structures, rapid evaluation of conditions of damaged structures after an earthquake, estimation of residual life of structures, repair and retrofitting of structures, maintenance, management or rehabilitation of historical structures.

• 대한전자공학회논문지
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• 제27권11호
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• pp.62-68
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• 1990

표준 Si 공정기술을 이용하여 칩의 크기가 $1.7{\times}1.7{mm^2}$인 소형 압저항형 Si 압력센서를 제작하고 그 동작 특성을 평가하였다. 제작된 센서는 크기 $1.0{\times}1.0{mm^2}$, 두께 $20{\mu}m$의 n형 Si 다이아프램상에 4개의 붕소 확산저항이 브릿지 형태로 연결된 칩 구조를 가지며 최종적으로 게이지압을 측장할 수 있도록 상온 상압하에서 패키징하였다. 이 센서의 동작특성은 상온에서 압력감도 $14.2{\mu}V/V{\cdot}mmHg$ 정격 압력범위 0~760mmHg, 최대 비선형성 $1.0{\%}$ FS로 평가되었다.

• Journal of Information Technology Applications and Management
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• 제12권2호
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• pp.79-106
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• 2005

This study, by adopting case study methodology, is focused on examining the present state and analyzing the cause of the digital divide, and suggesting policies for bridging the divide, specifically in view of SMEs. We have taken cases of manufacturing companies, visiting and interviewing 18 SMEs in 10 APEC member economies which show sharp difference in usage of ICT. In order to analyze the digital gap among SMEs, we used 5 variables that are composed of computer hardware, computer software, Internet, readiness of ICT, and performance of ICT adoption, while categorizing the cases into low and high tier based on the national ICT index. From a computer hardware perspective, the high tier (0.66) has almost double the number of PC’s per employee, compared with the low tiers (0.34). This gap can be explained by financial availability of low income and high tariff in the developing economies. In the computer software perspective, the SMEs in the low tier had some restrictive use of computer applications such as financial and accounting management and document management, while those in the high tier enjoyed more diversity in the use of applications such as inventory management, sales management, financial and accounting management, procurement management, CRM, and ERP. In view of the readiness of ICT, the difference in ICT infrastructure and financial status between the low and high tier was far wider than any other variables. As a result of ICT adoption, SMEs benefited in view of learning and growth, internal business processes, customer service, and financial affairs. To effectively bridge the digital divide between the low and high tier, actions such as setting up a secondary market of used computers among cooperating developed and developing countries, developing and diffusing good business applications, and building speedy, low-cost telecommunication infrastructures should be taken.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.41-46
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• 2006

This paper describes a marine watch system on a ship, which is aided by an image processing method. The system detects other ships through a navigational image sequence to prevent oversights, and it measures their bearings to maintain their movements. The proposed method is described, the detection techniques and measurement of bearings techniques are derived, and the results have been reported. The image is divided into small regions on the basis of the brightness value and then labeled. Each region is considered as a template. A template is assumed to be a ship. Then, the template is compared with frames in the original image after a selected time. A moving vector of the regions is calculated using an Excel table. Ships are detected using the characteristics of the moving vector. The video camera captures 30 frames per second. We segmented one frame into approximately 5000 regions; from these, approximately 100 regions are presumed to be ships and considered to be templates. Each template was compared with frames captured at 0.33 s or 0.66 s. In order to improve the accuracy, this interval was changed on the basis of the magnification of the video camera. Ships’ bearings also need to be determined. The proposed method can measure the ships’ bearings on the basis of three parameters: (1) the course of the own ship, (2) arrangement between the camera and hull, and (3) coordinates of the ships detected from the image. The course of the own ship can be obtained by using a gyrocompass. The camera axis is calibrated along a particular direction using a stable position on a bridge. The field of view of the video camera is measured from the size of a known structure on the hull in the image. Thus, ships’ bearings can be calculated using these parameters.

• 한국실내디자인학회논문집
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• 제21권5호
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• pp.372-380
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• 2012

This study investigates the examples of memorials in which participants can communicate and interact. Memorials as an urban public space provide various information and experiences to the visitors. The purpose of this study is to investigate the types of participants' experience and the characteristics of memorial space. The 9 examples of the memorials are selected and analyzed by the experience type of participants. This study summarizes the characteristics of spatial representation of memorials as follow; first, the interactions and communications of participants are main considerations in designing memorials. This study defines three types of participants' experience in memorials as educational, emotional and daily urban experiences. Second, the memorial space providing educational experience has narrative characteristics which are explanatory, representational, hierarchical and figurative. Memorials represent historical events and individuals in figurative ways. Participants in memorials learn the event, mourn for the dead and cure the grief through walking the guided route. Third, the memorial space providing emotional experience is indeterminate and open-ended characteristics which are contemplative, symbolic, and abstractive. While participants try to find the way to walk through and understand the meaning of the abstract forms by themselves, they interface the event and the victims in private and individual ways. Fourth, the memorial space providing daily urban experience is the familiar urban facilities embedded remembrance such as memorial square, bridge and fountain. Symbolism of memorials and effectiveness of urban facilities are engaged into the memorial design. They have functional, participatory, interactive and recreational characteristics. People experience the memorials involuntarily and casually during their daily lives. The memorials with urban facilities can be related to the present and the future of the city as well as the past of the city.

• 한국항해항만학회지
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• 제33권1호
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• pp.35-41
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• 2009

워터젯이 탑재된 RIB(Rigid Inflatable Boat)형태의 무인수상선을 인한 경유점 추적 제어 알고리즘을 설계하였고, 성능 검증을 위해 실해역 시험을 수행하였다. 본 연구에서 사용된 RIB형 무인수상선의 경유점 추적제어를 위해서는 방향제어를 위해 버킷각을 제어하여야 한다. 우선, 육상 관제소에 미리 입력된 경유점들의 위경도 등의 위치정보들을 바탕으로, 목표 방향각을 실시간 계산한다. 그리고, 무인수상선에 탑재된 마그네틱 콤파스 등의 센서로부터 받은 선수각 및 선수각속도의 값과 PD 제어기법을 이용하여, 버킷각 명령을 실시간 계산한다. 본 연구에서는, 바람 등의 외력으로 인한 표류각을 보정하기 위해 일정속도 이상에서는 실침로(Course Of Ground, COG)를 사용하였다. 또한, 설계된 경유점 추적 제어 알고리즘을 검증하기 위해 부산 광안대교 근처 해역에서 육상관제소를 설치하고, 실선 시험을 수행하였다. 본 논문에서는, 설계된 무인 경유점 추적 제어 알고리즘의 시험결과를, 유인으로 제어한 결과 및 상용추적제어기로 제어한 결과들과 비교 분석하였다.