• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1294-1300
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• 2010

In an environment where all nodes move, the sensor node receives anchor node's position information within communication radius and modifies the received anchor node's position information by one's traveled distance and direction in saving in one's memory, where if there at least 3, one's position is determined by performing localization through trilateration. The proposed localization mechanisms have been simulated in the Matlab. In an environment where certain distance is maintained and nodes move towards the same direction, the probability for the sensor node to meet at least 3 anchor nodes with absolute coordinates within 1 hub range is remote. Even if the sensor node has estimated its position with at least 3 beacon information, the angle ${\theta}$ error of accelerator and digital compass will continuously apply by the passage of time in enlarging the error tolerance and its estimated position not being relied. Dead reckoning technology is used as a supplementary position tracking navigation technology in places where GPS doesn't operate, where one's position can be estimated by knowing the distance and direction the node has traveled with acceleration sensor and digital compass. The localization algorithm to be explained is a localization technique that uses Dead reckoning where all nodes are loaded with omnidirectional antenna, and assumes that one's traveling distance and direction can be known with accelerator and digital compass. The simulation results show that our scheme performed better than other mechanisms (e.g. MCL, DV-distance).

• Journal of the Korea Institute of Building Construction
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• v.21 no.1
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• pp.11-19
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• 2021

The aim of the research is providing a fundamental data on quality and constructability of direct tile setting method depending on various cement to sand ratio for tiling dry cement mortar. A large number of tile setting failures reported is related with the cement mortar and its construction for tiling. Because of different materials of tiles, the properties of tiling dry cement mortar, an adhesive for tiling, can influence on quality and constructability of tiling differently. Practically, the easiest way of controlling the properties of the tiling dry cement mortar is to control the proportion of cement and sand. Hence, in this research, sand to cement ratio (S/C) was controlled. Since there is no standarized method on evaluating performance of dry cement mortar for tiling, a several sensory evaluation methods were suggested and executed. According to the experiments conducted in this research, the adhesive performance of cement mortar for tiles can be different depending on the sides such as tile and substrate. Additionally, depending on S/C, finishability, initial adhesive performance, and tile shifting resistance can be changed for ceramic tile. Therefore, under the conditions of this research, about 5 of S/C can be recommended for appropriate performace of tiling dry cement mortar.

• Journal of the Korean Society of Food Culture
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• v.3 no.1
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• pp.7-16
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• 1988

An epigraph is an inscription mainly on a metal or stone monument, but some cases on bones or tortoise carapaces, ceramics, and coins. The '茶' inscriptions in 251 epigraphs in Korea are on 16 monuments, one tile, and one ceramic. By kingdom 5 belongs to shilla and 13 to Korea. The first '茶' inscription in on the Changsung-Tap of Borimsa Temple in Changhung-Kun, Chullanam-Do, which was established in 884 A.D. Religiously most of them are related to Buddism. Tea was most valued among valuables like gold, perlume, beads, etc. and so bestowed by kings. The study of epigraphs shows that our tea culture had most prospered diring the Kingdoms of Shilla and Korea.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.782-783
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• 2011

국내의 전력수요는 지속적으로 성장 하고 있으며, 더불어 전력산업도 대용량화, 고밀도화하고 있고 전력계통의 규모가 커짐에 따라 고장전류도 증가하고 있기 때문에 이로 인한 사회적 경제적 파급도 점차 증대되고 있다. 또한 최근에는 친환경 및 고신뢰도의 전력계통을 갖추도록 사회적 요구가 증가하고 있다. 이에 정부와 한국전력공사는 친환경적인 초전도 케이블과 초전도 한류기라는 신기술을 전력계통에 적용하여 운전함으로써 녹색기술의 사회적 요구에 부응하고, 미래 전력산업을 선도하고자, 국내최초로 초전도 전력기기 실계통 적용을 위하여 이천 변전소 초전도 시범사업을 정부지원으로 한국전력이 주관하고 제작업체가 참여하는 방법으로 추진하고 있다. 성공적인 초전도 전력기기의 실계통 적용을 위해서는 초전도 전력기기에 대한 실계통 운영시스템이 반드시 필요한데, 본 논문에서는 이천변전소에서 설치 운영될 22.9kV 초전도케이블과 22.9kV 초전도한류기의 실계통 병입과 관련하여 국내전력계통에서 운영하고 있는 SCADA 시스템과 호환할 수 있도록 계통운영자 관점에서 설계한 국내최초 초전도기기 실계통 운영모니터링시스템을 소개하고자 한다.

• The Korean Journal of Emergency Medical Services
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• v.21 no.3
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• pp.7-16
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• 2017

Purpose: The purpose of the study was to investigate the effects of laryngeal mask airway (LMA) insertion from different positions, using different methods, on the quality of the insertion, for identifying a more convenient and effective insertion method. Methods: In a model ambulance, 30 paramedic students performed the LMA insertion procedure, in four different settings, combinations of the rescuer's position (at the head end of the patient, at the side of the patient), and insertion technique (index finger insertion, thumb insertion), in a randomized order. Quality of insertion index and convenience of use were measured. Results: The quality of insertion index (tidal volume, gastric insufflation, airway pressure, airway sealing pressure, midline positions, insertion success grade, and insertion time) were not significantly different among four different settings. However LMA insertion from the anterior (head) end, using the index finger method compared to the thumb method was found to be significantly more convenient. Conclusion: We recommend using the more convenient and familiar LMA insertion method, between index finger insertion and thumb insertion, regardless of rescuer's position.

• Journal of Mushroom
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• v.11 no.1
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• pp.21-23
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• 2013

We aim at providing consumers and farmers with various parts of mushrooms through development of new mushroom cultivation. For the mass artificial cultivation, we elucidated suitable environment conditions of Neolentinus lepideus. The results were summarized as follows. For the efficient cultivation of N. lepideus, temperature of mycelial growth and development of the fruit body were suitable $20{\sim}23^{\circ}C$ and $20^{\circ}C$, respectively.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.1
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• pp.49-55
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• 2017

This study proposes a new approach to Control and trajectory generation of a 8 DOF human robot arm with computational complexity and singularity problem. To deal with such problems, analytical methods for a redundant robot arm have been researched to enhance the performance of research, we propose an analytical kinematics algorithm for a 8 DOF bipped dual robot arm. Using this algorithm, it is possible to generate a trajectory passing through the singular points and intuitively move the elbow without regarding to the end-effector pose. Performance of the proposed algorithm was verified by simulation test with various conditions. It has been verified that the trajectory planning using this algorithm.

• Journal of Korean Society of Steel Construction
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• v.26 no.5
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• pp.375-383
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• 2014

In Seoul, total 166 places of foot-bridges were constructed but a study on correlation between resonance occurrence status by gait vibration and natural frequency by each span and that between span based on structural system and natural frequency is very unsatisfactory in reality. Consequently in this study, time series wave form, power spectrum and natural frequency were analyzed based on resonance occurrence by targeting 65 places of foot-bridges being constructed in Seoul through convenient and simple portable vibration meter.

• Progress in Superconductivity and Cryogenics
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• v.7 no.1
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• pp.37-41
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• 2005

This paper describes the construction scheme of new distribution system using HTS(High Temperature Superconducting) power equipments such as cable, transformer and FCL(fault current limiter). At present, one of the most serious problems in distribution power system, especially for metropolitan complex city, is to obtain the ROW for cable line routes, space for downtown substations and satisfy the environmental protection caused by NIMBY phenomena. Unfortunately, it is expected that this situation will get more and more worse. As the HTS technology to apply in power system Is developed, HTS cable utilizing mass-capacity characteristic can be a useful countermeasure to overcome this problem. This paper describes the application methodology of 22.9kV HTS cable with low-voltage, mass-capacity characteristics replacing the 154kV conventional cable. By applying 22.9kV HTS cable, the HTS transformer with higher capacity for the reduction of space and transformer numbers of downtown substation is necessary. Also, if the leakage Impedance of HTS transformer is same as or lower than that of conventional transformer, the fault current of 22.9kV bus will increase because the HTS transformer capacity is larger than that of the conventional transformer. This means the parallel application of HTS-FCL to reduce the fault current in addition to the HTS cable and transformer can be necessary. With the basic construction scheme of new distribution system, this paper describes the future study points to realize this new distribution system using HTS equipments.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.4
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• pp.394-402
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• 2000

This paper proposes a bifurcation theory method applied for voltage stability analysis and shows the improvement of voltage stability by attaching the FACTS devices in the power system. A power system is generally expressed by a set of equations of highly nonlinear dynamical system which includes system parameters(real or reactive power). Sometimes variation of parameters in the system may result in complication behaviors which give rise to system instability. The addition of FACTS increases the range of voltage stability in the power system. The effect of FACTS which improves voltage stability are illustrated in the case studies by delaying of Unstable Hopf Bifurcation and Saddle Node Bifurcation.