• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.444-444
• /
• 2008

For the polymer tandem cell, simple and advantaged solution-based method to electron transport intermediate layer is presented which are composed $TiO_2$ nanoparticles. Device were based on a regioregular Poly(3-hexylthiophene)(P3HT) and [6,6]-phenyl $C_{61}$ butyric acid methyl ester($PC_{60}BM$) blend as a donor and acceptor bulk-heterojunction. For the middle electrode interlayer, the $TiO_2$ nanoparticles were well dispersed in ethanol solution and formed thin layer on the P3HT:PCBM charge separation layer by spin coating. The layer serves as the electron transport layer and divides the polymer tandem solar cell. The open-circuit voltage (Voc) for the polymer tandem solar cells was closed to the sum of those of individual cells.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
• /
• 2010.06a
• /
• pp.175-179
• /
• 2010

This study was to evaluate of installation location and management problem for a closed circuit television according to the present situation and installation environment when the CCTV doesn't take a location, surrounding environment, mechanical function in the campus. This methodology used network analysis, mechanical characterization and Streetlight illuminance. As a result, we confirmed in Kyung-Buk National University that was problem of unrelated location of walk pattern in students, a short of illuminance location, only 25 CCTV can be used to crime prevention of student in the night but, the other one is need to some improvement under 44 CCTV.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.1560-1565
• /
• 2007

A surveillance system is used many industrial places, and public places to monitor the present situation. Most of the existing surveillance system is composed of the monitors and a lot of cameras that are installed each place to be monitored. The system is usually using the CCTV, closed circuit television, system that is a passive surveillance system. Urban transit operation corporations use the passive surveillance system to monitor the situation of the passengers, and the status of the important facilities. However the officers or operators cannot monitor all of the situation or status constantly, and cannot respond to emergency. In this paper, we propose a sensor network-based intelligent surveillance system to solve these problems. The proposed system is composed of a lot of intelligent sensors that can determine the present status and integrated processor units to detect more precisely events using the information from the sensors. The sensors and the integrated processor are connected by communication network. The proposed system can be installed and used without a lot of change of the existing facilities such as the enormous communication bandwidth increase.

• Journal of Korean Society of Water and Wastewater
• /
• v.29 no.6
• /
• pp.693-702
• /
• 2015

The objective of this study is to investigate and evaluate that a roadside tree root intrudes sewer network systems. Two approaches were performed to assess the characteristics of tree root intrusion. First, the characteristics of tree roots that had invaded sewers were directly observed by means of closed-circuit television inspection robot. Second, the intrusion proportions of tree root into rain gutters in the sampling area were investigated. As tree species of low intrusion proportions, the results indicated that Ginkgo biloba Linn. and Acer buergerianum Miq. were 1.7% and 4.3%. On the other hand, tree species of high intrusion proportions were Metasequoia glyptostroboides Hu et Cheng, Ulmus davidiana var. japonica Nakai and Zelkova serrata Makino as 22.2%, 20.4%, and 17.6% respectively. In particular, sewers and gutters around Zelkova species should be the focus of maintenance work because of the high proportion of these trees on roadsides.

• Convergence Security Journal
• /
• v.15 no.1
• /
• pp.83-89
• /
• 2015

In the wide area surveillance system including many CCTVs, application for remote realtime monitoring is designed and implemented. The applications using Xcode provide secure administrator interface from headquarters. Through the efficient and intuitive interface, it delivers real-time context reports and inference results. For the user convenience, it includes push alarm of events, SNS, Media streaming service for real-time monitoring uses Wirecast and Wowza media server. Wowza stream engine provides URL accommodating development specification. Mobile devices can receive real-time stream data. Performance evaluation in the processing is provided.

• Progress in Superconductivity and Cryogenics
• /
• v.6 no.2
• /
• pp.29-34
• /
• 2004

The linear type flux pump aims to compensate a little bit decremental persistent current of the HTS magnet in NMR and MRI spectrometers. The flux pump mainly consists of DC bias coil, 3-phase AC coil and Nb foil. The persistent current in closed superconductive circuit can be easily adjusted by the 3-phase AC current, its frequency and the DC bias current. In the experiment, it has been investigated that the flux pump can effectively charge the current in the load coil of 543 mH for various frequencies in 18 minutes under the DC bias of 10 A and the AC of 5 $A_{rms}$. The maximum magnitudes of pumping current and load magnet voltage are 0.72 A/min and 20 ㎷, respectively. Based on simulation results by the FEM are proved to nearly agree with experimental ones.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1027-1028
• /
• 2008

Most of the urban transit operation company in Korea have a passive surveillance system to monitor the status of the passengers and facilities in the urban transit service area. The surveillance system is based on CCTV, closed circuit television, and several sensors, such as a fire sensor. However, this system has some limitations to prevent and cope with the emergency quickly. So the urban transit operation companies have plans to be change their surveillance system to be active. The active surveillance system has an intelligent function to detect the event predefined by managers automatically. To construct the active surveillance system, there are a standard concept design and a function analysis. In this paper, we propose the classification of the functions of the active surveillance system for urban transit. We divide the functions into five parts, ordinary monitoring, safety monitoring, environment monitoring, administration support, and record management. And we describe the systems related to the every functions to clarify the classified functions.

• Journal of Power Electronics
• /
• v.16 no.2
• /
• pp.572-583
• /
• 2016

In view of the speed control characteristics of induction traction motors and the problems of direct torque control (DTC) algorithms in current applications, this paper presents a DTC algorithm characterized by a symmetrical polygon flux control and a closed loop power control in the constant-torque base speed region and constant-power field-weakening region of induction traction motors. This algorithm only needs to add a stator flux control algorithm to the traditional DTC structures. This has the benefit of simplicity, while maintaining the features of traditional algorithms such as a rapid dynamic response, uncomplicated control circuit, reduced dependence on motor parameters, etc. In addition, it obtains a smoother flux trajectory that is conducive to improvement of the harmonic elimination capability, the switching frequency utilization as well as the torque and power performance in the field-weakening region. The effectiveness and feasibility of this DTC algorithm are demonstrated by both theoretical analysis and experimental results.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.49 no.7
• /
• pp.359-364
• /
• 2000

This paper is introducing a newly developed spark-gap switch with dual trigger system, into which the current from the voltage source is injected along with the test sequence during the synthetic testing of high voltage circuit-breaker. The currently-used spark gap switch is narrow in operating range due to the use of the method of triggering energy being injected by single way. As a result, the frequent happening of misoperation has greatly reduced the test quality and test efficiency and has required the cost of maintenance excessively. In this study, accordingly, in order to basically remove these problems, another triggering system is installed to the opposite direction on the existing triggering system; attaching the same time and the same rising time of pulse wave as on the existing system, so that at a comparatively trigger gap distance from the main electrode(the gap can be operated at 60% of self-break voltage, while at 80% in the current system), the main electrode has been enabled to be closed by the development of spark gap switch with dual trigger system.

• Korean Security Journal
• /
• no.51
• /
• pp.199-219
• /
• 2017

This research examined the degree to which open-street closed-circuit television (CCTV) systems reduced crime in the vicinity of elementary schools. Information including crime dates, locations, and types around nine elementary schools in the city of Chuncheon in South Korea where the cameras had been installed was gathered and assessed. By employing the Poisson regression with "month" as the unit of analysis and controlling for the days in each month, the average monthly temperatures, and crime trends, the research results show that the CCTV installations had an impact on the reduction of total crime and serious crime. However, the same reduction effect was not observed for disorder crime. Therefore, the results of this study suggest that the employing CCTV is an effective way to control overall crime rates, especially serious crime.