• 한국정보통신학회논문지
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• 제8권5호
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• pp.1004-1009
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• 2004

컴퓨터 시스템에서의 시각 메커니즘은 기본적이고 필수적인 요소로써 현재 시각의 유지 및 프로세스 점유 시간, 디스크 I/O 등, 시스템의 각종 성능 평가를 위한 척도이다. 분산 시스템에서 응용프로세스들은 시스템 내 여러 노드에서 동시에 수행되며 정확한 결과를 얻기 위해서는 노드 간 시각 동기가 이루어져야 한다. 현재 통신망이 보편적 요소가 되면서 분산 환경 구성 및 네트워크 기반 운용이 일반화됨에 따라 시각 동기는 필수 사항이 되었다. 네트워크 시각 서버는 시스템의 지역 클럭을 표준 참조 시각원에 동기시킴으로써 정확하고 정밀한 시각을 획득, 유지하고 표준 시각 동기 프로토콜을 통해 시각 정보를 네트워크에 분배한다. 본 논문은 네트워크 시각 동기를 위한 시각 서버의 설계 및 구현에 대해 제시한다. 시스템은 표준 참조 시각원으로 GPS (Global Positioning System)를 사용하며 NTP (Network Time Protocol)를 통해 표준시 (UTC: Universal Time Coordinated)를 제공한다.

• 한국콘텐츠학회논문지
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• 제12권12호
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• pp.447-458
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• 2012

본 연구는 특화거리조성을 통한 도시재생 및 지역 활성화 특화전략을 위한 기초연구로서 부산시의 대표적인 특화거리의 하나인 '보수동 책방골목'을 대상으로 특화거리의 조성내용, 조성주체, 조성과정의 측면에서 분석하였다. 이와 더불어 국외사례고찰의 대상으로 서점을 통한 특화거리 조성의 대표적인 국외사례인 '헤이 온 와이' 책 마을과 '간다 고서점 거리'를 선정하여 보수동 책방골목과 비교분석하여 시사점을 도출하였다. 국내외 사례의 분석을 통한 시사점은 다음과 같다. 첫째, 특화거리의 내용적 측면에 있어서는 책과 관련된 관광 및 출판 산업 등과의 연계를 통한 지역의 활성화와 지역정체성을 기반으로 하는 하드웨어 및 소프트웨어의 개발이 필요하다. 둘째, 특화거리를 조성하고 운영 관리하는 주체는 주민과 상인이 주도가 되고 공공은 이를 지원하는 역할을 하는 '주민 상인주도+공공지원'의 형태가 필요하다. 셋째, 특화거리의 하드웨어 및 소프트웨어의 조성과 운영 및 관리의 전 과정에 있어서 주민 및 상인을 중심으로 한 커뮤니티의 적극적이고 활발한 참여와 지속적인 노력이 필요하다.

• 한국정보시스템학회지:정보시스템연구
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• 제26권3호
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• pp.247-271
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• 2017

Purpose This study aims to propose a framework for safety in domestic walking tourism, which defines the scope and type of safety information for tourists. Also, the framework provides a systematic classification for safety information in walking tourism. As the importance of safety in walking tourism due to the frequent occurrence of crimes and unexpected accidents increases, it is necessary to provide tourists with safety information on walking courses rapidly and systematically. However, most administrators (e.g., local governments) have mainly focused on providing tour information on walking courses through Internet websites or mobile apps, overlooking the safety issue. Besides, there is a lack of understanding of safety not only in walking tourism but also in the whole tourism industry. Design/methodology/approach This study proposes the framework that covers all possible safety-related information in walking tourism. Furthermore, to validate its availability, this study analyzes eight major platforms which offer tour information to tourists by applying the framework. Findings The major findings of this study are as follows. First, all platforms considered in this study do not provide any information on tourism safety, focusing on the provision of tour information. Second, three platforms currently provide an SOS function which means post-safety information. That is, no safety information is provided to prevent safety issues in advance. Finally, despite the increase of social concerns, all platforms do not provide safety information on public order and diseases in the social disaster classification as well as environmental pollution in the natural disaster classification. The details and implications of the findings are presented.

• Steel and Composite Structures
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• 제19권5호
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• pp.1115-1144
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• 2015

Current climate conditions along with advances in technology make further design and verification methods for structural strength and reliability of wind turbine towers imperative. Along with the growing interest for "green" energy, the wind energy sector has been developed tremendously the past decades. To this end, the improvement of wind turbine towers in terms of structural detailing and performance result in more efficient, durable and robust structures that facilitate their wider application, thus leading to energy harvesting increase. The wind tower industry is set to expand to greater heights than before and tapered steel towers with a circular cross-section are widely used as more capable of carrying heavier loads. The present study focuses on the improvement of the structural response of steel wind turbine towers, by means of internal stiffening. A thorough investigation of the contribution of stiffening rings to the overall structural behavior of the tower is being carried out. These stiffening rings are placed along the tower height to reduce local buckling phenomena, thus increasing the buckling strength of steel wind energy towers and leading the structure to a behavior closer to the one provided by the beam theory. Additionally to ring stiffeners, vertical stiffening schemes are studied to eliminate the presence of short wavelength buckles due to bending. For the purposes of this research, finite element analysis is applied in order to describe and predict in an accurate way the structural response of a model tower stiffened by internal stiffeners. Moreover, a parametric study is being performed in order to investigate the effect of the stiffeners' number to the functionality of the aforementioned stiffening systems and the improved structural behavior of the overall wind converter.

• Nuclear Engineering and Technology
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• 제47권6호
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• pp.729-737
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• 2015

Wireless communication technologies, especially smartphones, have become increasingly common. Wireless technology is widely used in general industry and this trend is also expected to grow with the development of wireless technology. However, wireless technology is not currently applied in any domestic operating nuclear power plants (NPPs) because of the highest priority of the safety policy. Wireless technology is required in operating NPPs, however, in order to improve the emergency responses and work efficiency of the operators and maintenance personnel during its operation. The wired telephone network in domestic NPPs can be simply connected to a wireless local area network to use wireless devices. This design change can improve the ability of the operators and personnel to respond to an emergency situation by using important equipment for a safe shutdown. IEEE 802.11 smartphones (Wi-Fi standard), Internet Protocol (IP) phones, personal digital assistant (PDA) for field work, notebooks used with web cameras, and remote site monitoring tablet PCs for on-site testing may be considered as wireless devices that can be used in domestic operating NPPs. Despite its advantages, wireless technology has only been used during the overhaul period in Korean NPPs due to the electromagnetic influence of sensitive equipment and cyber security problems. This paper presents the electromagnetic verification results from major sensitive equipment after using wireless devices in domestic operating NPPs. It also provides a solution for electromagnetic interference/radio frequency interference (EMI/RFI) from portable and fixed wireless devices with a Wi-Fi communication environment within domestic NPPs.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.279-284
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• 2009

Traditionally, so-called "industrial waste gases", such ad exhaust from boilers at industrial installations and a large quantity of soot discharged from power station, before their release into the atmosphere, have been on occasion subjected to an air cleaning process to remove fine particles that may pollute the atmosphere (such as mist and dust containing various powdery or oily substances and moisture from industrial waste gases). The release of industrial waste gases containing these particles directly into the atmosphere poses a serious threat to the earth environment; and recovery of these noxious substances is required by law in some countries and local governments. in urban areas, air pollution from automobile exhaust and others creates a serious condition. Some homes are equipped with and use indoor air purifiers. In many of the kitchens of restaurants, smoke generated during cooking and otherwise contaminated air are cleansed by air purifiers before being released outside or recycled inside. For the dust collecting devices to recover the fine particles contained in contaminated air, the cause for air pollution and how to purify air, many types based on various principles are known. Specifically, classified based on theories of particle collection, filtration, gravity, inertia, centrifugation, electricity, and cleaning types are cited as available processes. Among them, an appropriate type is selected according to the size or type of fine particles to be collected and conditions for installation. For the efficiency of dust collection, a filtration system (by using bag filters and others) and electric system are particularly outstanding and are therefore used widely in various areas of industry. In this research, rotary type high performance oil mist and smoke collecting system with self auto cleaning device equipped with the cleaning fluid spraying section is investigated.

• 여성건강간호학회지
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• 제25권1호
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• pp.112-123
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• 2019

Purpose: The objective of this study was to investigate the prevalence of antenatal depression in pregnant women and its influencing factors. Methods: With a cross-sectional survey design, a total of 396 pregnant women were recruited from a local obstetrics and gynecology clinic. Measurements included antenatal depression, perceived stress, predictors of depression during pregnancy, and demographic and obstetric characteristics. Results: Mean antenatal depression score was 8.20 (standard deviation=4.95) out of 30, falling into its normal range. However, the prevalence of antenatal depression was 35.9% when cut-point of 9/10 was used. The prevalence of antenatal depression among women in the first trimester was 31.4%. It was slightly increased to 34.9% in the second trimester but significantly increased to 40.5% in the third trimester. In multiple logistic regression analysis, experiencing prenatal anxiety (odds ratio [OR], 4.16), having no job (OR, 2.90), lower self-esteem (OR, 1.62), and higher perceived stress (OR, 1.32) were significant factors influencing antenatal depression. Conclusion: Negative feeling such as feeling anxious, lower self-esteem, and higher perceived stress during pregnancy are key factors affecting antenatal depression. Thus, antenatal nursing intervention focusing on pregnant women's feeling upon their job status is necessary to improve their antenatal psychological well-being.

• Geomechanics and Engineering
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• 제17권4호
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• pp.367-374
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• 2019

This study concluded the results of a research on the features of cement based permeation grout, based on some important grout parameters, such as the rheological properties (yield stress and viscosity), coefficient of permeability to grout ($k_G$) and the inject ability of cement grout (N and $N_c$ assessment), which govern the performance of cement based permeation grouting in porous media. Due to the limited knowledge of these important grout parameters and other influencing factors (filtration pressure, rate and time of injection and the grout volume) used in the field work, the application of cement based permeation grouting is still largely a trial and error process in the current practice, especially in the local construction industry. It is seen possible to use simple formulas in order to select the injection parameters and to evaluate their inter-relationship, as well as to optimize injection spacing and times with respect to injection source dimensions and in-situ permeability. The validity of spherical and cylindrical flow model was not verified by any past research works covered in the literature review. Therefore, a theoretical investigation including grout flow models and significant grout parameters for the design of permeation grouting was conducted in this study. This two grout flow models were applied for three grout mixes prepared for w/c=0.75, w/c=1.00 and w/c=1.25 in this study. The relations between injection times, radius, pump pressure and flow rate for both flow models were investigated and the results were presented. Furthermore, in order to investigate these two flow model, some rheological properties of the grout mixes, particle size distribution of the cement used in this study and some geotechnical properties of the sand used in this work were defined and presented.

• 한국정보통신학회논문지
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• 제23권10호
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• pp.1305-1310
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• 2019

현대의 농업은 자원위주의 농업에서 과학기술 위주의 농업으로 변하고 있다. 과학기술이 융합된 농업은 새로운 신성장 동력으로 인식하고 있으며, 지능적인 스마트팜을 구축하기 위하여 정부 및 지방자치단체, 연구소, 산업계가 협력하여 스마트팜에 필요한 각종 장치를 개발하여 보급하고 있다. 최근에는 클라우드 플랫폼을 구축하여 보다 지능적인 농업환경을 구축하는 연구가 진행되고 있다. 본 논문에서는 도시의 건물 옥상을 활용하여 여가시간의 활용과 농업활동을 체험할 수 있는 도심형 에너지 자립 스마트팜 구축방안을 제시한다. 또한, IT 기술을 활용하여 스마트팜의 다양한 데이터를 원격지 서버에서 데이터를 관리하고 스마트팜 내부 환경을 제어할 수 있는 HMI 모듈을 개발하여 자동 또는 반자동으로 스마트팜을 관리하도록 한다. 서비스 모델은 모바일 기반으로 스마트팜의 내부 환경을 관리할 수 있는 모델을 제시한다.

• 터널과지하공간
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• 제33권1호
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• pp.10-28
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• 2023

고준위방사성폐기물 처분장의 장기 안정성을 확보하기 위해서 암반 불연속면의 장기적인 전단 거동을 분석하고 그 안정성을 평가해야 한다. 암반 불연속면의 장기 전단 거동은 크리프 모델, RSF 모델로 모사될 수 있고, 전단 크리프 시험, 속도 단계 시험, 슬라이드-홀드-슬라이드 시험을 통해 모델에 필요한 파라미터를 결정하거나 여러 조건에서 전단 거동을 분석하는 실험을 수행할 수 있다. 기존 연구에 따르면 전단 실험을 위하여 직접전단시험기, 삼축압축시험기, 이축전단시험기가 주로 이용되었으며 현지 암반의 열-수리-역학적인 조건을 재현하기 위해 다양하게 개선된 장비가 이용되었고 그에 따라 다양한 양상의 전단 거동이 관찰되었다. 그러므로 국내 고준위방사성폐기물 처분장을 설계하기 위해서 처분장 부지의 암종, 열-수리-역학적 조건, 광물의 변성, 그리고 전단 저항의 회복 등을 고려하여 암반 불연속면의 장기 거동을 검토해야 한다.