• KSCE Journal of Civil and Environmental Engineering Research
• /
• 제43권1호
• /
• pp.99-107
• /
• 2023

Recently, the rate of death and safety accidents at construction sites is the highest among all kinds of industries. In order to apply artificial intelligence technology to construction sites, it is essential to secure a dataset which can be used as a basic training data. In this paper, a number of image data were collected through actual construction site, for which major construction equipment objects mainly operated in civil engineering sites were defined. The optimal training dataset construction was completed by annotation process of about 90,000 image dataset. Reliability of the dataset was verified with the mAP of over 90 % in use of YOLO, a representative model in the field of object detection. The construction equipment training dataset built in this study has been released which is currently available on the public data portal of the Ministry of Public Administration and Security. This dataset is expected to be freely used for any application of object detection technology on construction sites especially in the field of construction safety in the future.

• Journal of the Korea Society of Computer and Information
• /
• 제25권1호
• /
• pp.117-124
• /
• 2020

In this paper, we proposed a plan to maintain comfortable indoor air quality in nursing homes by suggesting ways to reduce items temporarily exceeding the reference values through real-time concentration variation analysis of indoor air quality. Five items including PM10, CO₂, CO, VOC, and Radon are measured at nursing homes in spring (April) and autumn (September) was carried out and all of the measured items were analyzed to satisfy the criteria set by the Indoor Air Quality Control Act. As a result of the analysis of the real-time concentration change, the concentration of CO₂ was close to the reference value based on the number of occupants in the sick room. Due to the disinfectant (alcohol) used to disinfect and the auxiliary tools (adhesive) used in the operation of the program such as making and coloring, it was analyzed to temporarily exceed the standard value in the hall. In conclusion, it is possible to provide pleasant indoor air quality and contribute to securing the nursing home's competitiveness if periodic ventilation, natural disinfectant and eco-friendly product are used in consideration of the thermal environment.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• 제37권1호
• /
• pp.19-29
• /
• 2000

Because the previous simulation tool for attitude control of satellite was designed for the modeling of rigid body and PD controller, the attitude error can be made more than the limitation value for keeping for communication link, and then the communication link can be lost at moving of satellite. So, for rapid attitude restoration and design of stable and modernized controller, the modelling of rigid body and flexible body structure for moving GEO and LEO satellites were performed. Also the minimum time controller is designed for the rapid restoration of attitude error at communication broken and to minimize the disconnection period from ground communication system during the satellite stationkeeping. The linear regulator is designed using the space state vector that is better than accuracy and stability of PD controller. Firstly the simulation was performed for comparison of the rigid and stability of PD controller. Firstly the simulation was performed for comparison of the rigid and flexible models using PD controller and the case of the pitch angle changing by ground command, and the case of the periodic north-south stationkeeping are performed for the analysis of response characteristics of each controller when the attitude is changed. As a result, the flexible body model represents more sililar results of real situation than the rigid body model. The minimum time controller can restore 7 times rapidly than PD controller for its lost attitude. The linear regulator has several merits for capability of adaptation against the external disturbance, stability and response time. In future, we can check the estimated results using this satellite model and controller for real operation. Futhermore the development of new controller and training can be supported.

• Journal of the Korean Institute of Gas
• /
• 제5권2호
• /
• pp.30-35
• /
• 2001

Presently, working gas pipelines are being subjected to the influence of construction vibration. Especially on subway and road construction, gas pipelines are being influenced to construction vibration caused by use of construction equipment, passage of a large-sized vehicle and blasting. Buried gas pipelines are subjected to the influence of vibration caused by blast in the vicinity of pipeline, exposed gas pipelines are subjected to the influence of vehicle vibration. Therefore, in the study, it is developed to vibration prediction program of gas pipeline by analyzing measured construction vibration. This program is able to predict vibration of gas pipeline according to field conditions by using the results of structural finite element analysis and empirical equation by reliability analysis. And, this program contains the database of construction vibration. Additionally, this program is able to compute estimated blast vibration equation using measured blast vibration data in the field and to form graph of allowable charging gunpowder per delayed-action with the change of blast velocity. Therefore, field workers are able to predict construction vibration around gas pipeline and estimate safety of gas pipeline.

• 한국방재학회:학술대회논문집
• /
• 한국방재학회 2011년도 정기 학술발표대회
• /
• pp.31-31
• /
• 2011

1990년 이후 공산체계인 구소련과 동구권이 몰락하고 세계적으로 탈냉전의 변화와 우리의 민주정부 수립 후 햇빛정책 등에도 불구하고 북한은 적화통일을 포기하지 않고 작년 11월에 연평도에 포격을 가하여 민간인과, 군이 2명이 사망하는 사건이 발생 하였다. 또한 북한의 공격은 과거의 포탄공격뿐만 아니라 미사일이나 화생방과 같은 생화학물질 탑재 가능한 공격이 예상된다. 이에 대비 정부에서는 고정시설의 화생방 방호는 일단유사시에 국민의 생명과 재산을 보호하는데 필수요소로서 집단보호개념에 도입하고 있으며, 현재 각 중요 대피시설 및 지자체의 기존 대피시설을 개인방호, 탐지, 제독, 운용절차를 포함한 실태파악 및 재래식 탄을 포함한 통합적인 조치를 마련하고 있다. 작년 2010년 11월 연평도에서의 북한 포격이후 우리는 서해5도나 접경지역 주민과 그리고 근접거리의 서울시민들이 안전하게 포격으로부터 피난 할 수 있는 민방위대피소에 대한 문제점이 대두되고 대책방안을 요구하고 있다. 소방방재청 기준에 따르면 직격(直擊) 핵폭탄을 제외한 화생방, 재래식 무기 공격에 견딜 수 있는 시설은 '1등급 대피시설'인데 서울에는 한 곳도 없다. 고층건물의 지하 2층 이하나 지하철, 터널 같은 2등급 대피시설도 폭격은 견딜 수 있지만 화생방 공격에는 취약하다. 지하상가 등 건축물의 지하층, 지하차도나 보도는 그보다 더 취약한 3등급이며 단독 주택의 지하층처럼 방호 효과가 떨어지는 곳이 4등급이다. 2등급으로 분류된 대피소의 경우 분류만 되어 있을 뿐 장기간 대피시 시민들이 사용 할 수 있는 거주공간이 아닌 임시 대피로서의 역할만 하고 있다. 본 연구에서는 민방위 기본법에 따라 지하에 $3.3m^2$ 당 4명 이상이 대피할 수 있는 규모의 공간을 갖추기만 하면 대피시설로 볼 수 있는 현 문제점과 1등급에서 4등급으로 나뉘어져있는 민방위 대피소와 대피소가 있지만 피난공간으로서의 역할과 구조적으로 안전한가에 대한 국내외 실태 분석을 통하여 분석한 결과 우리는 서해5도 대피시설의 반 이상이 무용지물이고 접경지 또한 피난시에 피난장으로서의 대피소가 난방이나, 구급품과 식구 시설 등이 구비가 되어 있지 않고 대피시설로 지정한곳이 간판이나 안내시설이 없다. 외국의 경우 스위스는 연방정부의 관리책임으로 전쟁이나 핵 확산에 따른 화생방 업무 전담팀을 두고 있으며, 방독면은 개인 방호물자로서 전국민 100% 보유하고, 각가정이나 건축, 시설물의 경우 화생방 표준 대피시설 설치관련 규정 마련 시행하고 있다. 대피시설은 화생방 방호가 가능한 지휘부용 대피시설과 일반 주민대피용 시설을 구분하여 설치운영하고 있으며, 전국에 650만개를 설치하고 있다. 결론은 대피시설이 북한 공경시 피난시설로의 활용방안을 모색 등급구분에 따른 현실적용 수정과 기존 대피소 보강과 재선별이 필요하고, 신축시 설계 표준설계안 그리고 기존의 대피소에 대한 보수, 보강방법 가이드라인과 장기간 거주에 대한 설비구축 등과 국민 대홍보등을 제안하였다.

• Clean Technology
• /
• 제23권4호
• /
• pp.345-356
• /
• 2017

The composting is a biological process that converts organic matter into useful resources such as fertilizers. It is a continuous transition of microbial communities to adapt changes in organic matter and environmental conditions (carbonation rate, temperature, humidity, oxygen supply, pH, etc.). Most of the composting plants are located in the proximity of the residential areas. It is a general scenario where government authorities receive complaints from the local residents due to release of odor from the composting, and has become a social problem in Korea. Identification of dominant microorganisms, understanding change in microbial communities and augmentation of specific microorganism for composting is vital to enhance the efficiency of composting, quality of the compost produced, and reduction of odor. In this paper, we suggest the optimum operation conditions and methods for compost depot to reduce odor generation. The selection of the appropriate microorganisms and their rapid increase in population are effective to promote composting. The optimal growth conditions of bacteria such as aeration (oxygen), temperature, and humidity were standardized to maximize composting through microbial degradation. The use of porous minerals and moisture control has significantly improved odor removal. Recent technologies to reduce odor from the composting environment and improved composting processes are also presented.

• Journal of Korea Water Resources Association
• /
• 제38권10호
• /
• pp.811-824
• /
• 2005

The ADCP is an instrument based on Doppler effect, which measures discharge of a river in a short time while crossing it. In this study we aim to make a comparison of the discharge results from a moving-vessel ADCP with those measured by velocity-area method at the same cross-section, and to investigate the characteristics of velocity and discharge data using ADCP. Bathymetry measured by ADCP almost coincides with that by direct depth measurements. Because velocity data from ADCP are essentially instantaneous, individual velocity profiles obtained by ADCP are rather different from time-averaged velocity profiles. But spatially averaged velocity profiles of the individual ADCP data near the comparable verticals have similar vertical velocity pattern with the time-averaged ones. The average velocity profile from repeatedly crossed data is also similar with the time-averaged one. In case of the velocity distribution, individual and spatially averaged data for the sub-width of mid-section method Have good agreement with those by velocity-area method. Discharge data determined by averaging several ADCP measurement transects have $0.1\%{\~}9.3\%$ of difference with those from velocity-area method, and as the number of measurement increases, the relative difference to the velocity-area method decreases.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• 제21권12호
• /
• pp.1380-1393
• /
• 2010

This paper presents a design, fabrication and the test results of planar active electronically scanned array(AESA) radar prototype for airborne fighter applications using transmit/receive(T/R) module hybrid technology. LIG Nex1 developed a AESA radar prototype to obtain key technologies for airborne fighter's radar. The AESA radar prototype consists of a radiating array, T/R modules, a RF manifold, distributed power supplies, beam controllers, compact receivers with ADC(Analog-to-Digital Converter), a liquid-cooling unit, and an appropriate structure. The AESA antenna has a 590 mm-diameter, active-element area capable of containing 536 T/R modules. Each module is located to provide a triangle grid with $14.7\;mm{\times}19.5\;mm$ spacing among T/R modules. The array dissipates 1,554 watts, with a DC input of 2,310 watts when operated at the maximum transmit duty factor. The AESA radar prototype was tested on near-field chamber and the results become equal in expected beam pattern, providing the accurate and flexible control of antenna beam steering and beam shaping.

• Korean Journal of Food Science and Technology
• /
• 제29권6호
• /
• pp.1222-1227
• /
• 1997

Effects of the physical properties of solvent system such as pH and polarity change by salt addition in solvent system were investigated by using high speed countercurrent chromatography apparatus (Model CCC-1000, Pharm-Tech Research Corp. USA). The changes of pH and interfacial tension in solvent system of high speed countercurrent chromatography did not significantly affect on retention of stationary phase, but induced remarkable changes in the partition coefficient of ginkgo flavonoids, kaempferol, quercetin and isorhamnetin. The partition coefficients of ginkgo flavonoid standard increase with an increased pH of solvent system and quercetin sharply increased at pH 10.0. Retention of stationary phase decreases with an increased concentration of KCl in butanol of solvent system. Interfacial tension between two phase in solvent system of hexane increases with an increased concentration of KCl. The polarity of solvent system significantly changes the partition coefficients of ginkgo flavonoid.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• 제50권3호
• /
• pp.203-214
• /
• 2022

As the global demand for small satellites weighing less than 500 kg increases, the development and operation of dedicated small launch vehicles increase significantly. The responsiveness of a launch vehicle that puts a small satellite into a target orbit at the desired time is attracting attention. As a result, interest in the air launch is increasing in the rapid establishment of a constellation. As the demand for small satellites in south Korea increases, this study performed analyses on the applicability of an air launch vehicle using a large civil aircraft considering the geographical environment. In terms of responsiveness, mission response times were compared and analyzed for air launch vehicles and ground small and large vehicles. In addition, an air vehicle and a small ground vehicle were quantitatively compared and analyzed for the orbital insertion performance. As a result of the analysis, the air launch vehicle has limited responsiveness in Korea regarding rapid satellite constellation establishment. However, it can be an effective alternative for low inclination angle orbit insertion with the benefit of a fast turnaround time. Furthermore, the performance of the orbital injection is close to that of the ground small launch vehicle, and the high efficiency in terms of the required propellant mass is possible, so air launch can be an effective launch means for putting small satellites into orbit in Korea.