• Proceedings of the Safety Management and Science Conference
• /
• 2002.05a
• /
• pp.263-268
• /
• 2002

국내 공항에서 보유하고 있는 제한된 주기장에 대한 이용률과 주기되어 있는 항공기의 탑승에 소요되는 시간 및 도보거리는 공항의 운영 및 승객의 편리성 평가에 주요한 척도가 되고 있으며, 공항의 주요 운영 목표는 합리적인 항공기 주기장 배정을 통한 주기장 이용률의 최대화 및 터미널 이용 승객의 편리성 증대라 할 수 있다. 이에 본 연구에서는 대상 공항의 시설배치, 터미널 구조, 공항의 이용 승객 등을 고려하여 사용 가능한 주기장의 이용률의 최대화하고 터미널에서의 여객 이동거리를 최소화하는 주기장 배정 알고리즘의 개발과 그 결과를 국내 공항에 적용시키는 것을 그 목적으로 한다. 이를 위하여 기존의 GAP 정식화 모델을 최적화 소프트웨어인 LINGO를 활용하여 다중 시간 주기를 갖는 복잡한 문제를 단일 시간주기를 갖는 문제로 변환하기 위한 접근 방법을 제시함으로써 기존의 OR 접근 방법이 가지는 최적해 산출을 위한 긴 소요시간의 문제를 해결하고 실제 공항에 적용하여 실시간 의사결정을 위한 배정 결과를 제공하였다. 본 연구를 통하여 현재 발견적 기법에만 의존하여 수행되는 주기장 배정결과를 최적화 알고리즘을 통하여 산출함으로써 공항의 주요한 운영 목표인 항공사 및 여객의 시간 비용을 최소화할 수 있다. 또한 기상 악천후로 인한 항공기의 이착륙 지연이 발생할 경우 복잡한 문제를 배정 알고리즘에 의해 신속히 해결함으로써 공항 운영의 효율성뿐만 아니라 공항 안전에도 기여할 수 있을 것이다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.11a
• /
• pp.463-466
• /
• 2008

The weapon systems with a liquid propulsion engine have been used for various purposes and demands of the liquid fuel with variety of properties for its operational purposes and environment. The cyclic hydrocarbons including norbornane or dicyclopentane structures have many applications to the guided weapon systems due to the high density and high energy characteristics, also efforts have been given in many fields. In this study, the cyclic hydrocarbons that we designed and fabricated were investigated to obtain tendency on the structures.

• Journal of the Korean Society of Industry Convergence
• /
• v.23 no.6_2
• /
• pp.989-998
• /
• 2020

Recently, demands for large-capacity electronic loads are increasing in various industries such as a reliability test for the performance of a DC power supply device or a dummy-load for improving the stability of an independent microgrid to be actively built in the future. The electronic load required in these various fields requires an operation such as a continuously variable resistance load while minimizing the switching harmonic component generated in the electric load current in order to reduce the influence of interference from the load peripheral device. Electronic loads require a system that minimizes switching current ripple for load control. Therefore, in this paper, we propose a three-level module converter structure to reduce the current ripple of an electronic load, and a multilevel interleaved power converter topology to reduce the current ripple. The validity of the proposed electronic load, 3-level 6 interleaver converter, was verified by simulation and experiment. In addition, the user's convenience was provided by applying the emotional command curve interface method.

• Korean Journal of Microbiology
• /
• v.49 no.2
• /
• pp.146-149
• /
• 2013

Bacteria of genus Vibrio are Gram-negative, curved, halophilic, nonspore-forming bacteria, autochthonous inhabitans of the marine and estuarine environments. Some of the Vibrio species such as V. parahaemolyticus, V. vulnificus, and V. cholerae are associated with human disease. Each year many people have been suffering from food-borne disease caused by the ingestion of seafood. In this study, we have monitored antibiotic resistance of this microorganism in 6 coastal areas of West Sea by sampling shellfish monthly. Vibrio spp. were detected from 23.3% of 120 samples analyzed using TCBS agar plates as well as API 20E kit. Among 16 antibiotics tested, resistance to vancomycin and ampicillin was observed in 82.1% of the isolates, and Vibrio spp. resistant to rifampin (71.4%) and cephalothin (53.6%) were also high. Most of the isolates were sensitive to chloramphenicol (92.9%), sulfamethoxazole/trimethoprim (92.9%), and tetracycline (96.4%). About 71.4% of the isolates showed multiple drug resistance toward 3 antibiotics including vancomycin and ampicillin.

• The KIPS Transactions:PartA
• /
• v.10A no.6
• /
• pp.643-650
• /
• 2003

This paper presents a new submesh allocation scheme for mesh-connected multicomputer systems. The key idea in the proposed allocation scheme is to reduce the submesh search time using classified free submesh lists (CFSL). This scheme reduces the submesh search time by classifying independent free submeshes according to their types (square, horizontal rectangle, vertical rectangle) and searching the best-fit submesh from the classified free submesh list. When no suitable submesh is found, the search can be continued by using the expansion index (El), which is stored as an attribute of each submesh, is used to form a larger submesh. Through simulation, we show that the proposed strategy improves the performance compared to previous strategies with respect to submesh search time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 1999.11a
• /
• pp.101-105
• /
• 1999

Electronic Toll Collection(ETC) System makes the telecommunication possible between the Beacon and the On Board Unit(OBU) in vehicle at the highway. In this paper, the propagation path of microwave is modelled and the induced voltage of receiving antenna is analyzed numerically according to multi-path fading effort. In this modelling, we consider the weather condition, polarization and antenna radiation pattern. Also, we suggest the diversity technique in order to re duce the fading effect. In the result, the lading effort is reduced significantly in case of the vertical polarization at the rain condition. The circular polarization is the most desirable in this application. The antenna which has the high directivity, is also desirable. Using the space diversity technique at the Beaten, the fading effect is reduced as the distance increases between the Beacon and OBU. These results are presented at the graphs whose axes are related to the magnitude of received voltage(dB) and the distance of the beacon and a vehicle.

• Journal of the Korean Geotechnical Society
• /
• v.22 no.5
• /
• pp.47-57
• /
• 2006

The shear wave velocity is related with the stiffness of granular skeleton and mass density. The shear stiffness of the granular skeleton remains unaffected by the presence of the fluid. Bender elements are convenient shear wave transducers for instrumenting soil cells due to optimal soil-transducer coupling. This study addresses the principles of the shear wave, the design and implementation of bender elements including electromagnetic coupling prevention, directivity, resonant frequency, detection of first arrival, and near field effects. It is shown that electromagnetic coupling effects can be minimized using parallel-type bender elements. Thus, the in-plane S-wave directivity is quasi-circular. The resonant frequency of bender element installations depends on the geometry of the bender element, the anchor efficiency and the soil stiffness. One of the most cumbersome parts in the bender element test is near field effects, which affect the selection of arrival time. The selection of the first arrival within the near field Is effectively solved by the multiple reflection technique and signal matching technique. Bender elements, which requires several considerations, may be effective tools for the subsurface characterization by using S-wave.

• Korean Security Journal
• /
• no.47
• /
• pp.61-84
• /
• 2016

The objective of this study is to closely examine the relationship between intrinsic extrinsic job satisfaction and organizational citizenship behavior and closely examine a moderation effect that job characteristic variable has, focusing on workers in private security guard industry. In order to attain the above-mentioned objectives, a purposive sampling method was used as sampling method. Data on 207 people were used for analysis. A frequency analysis, correlation analysis, reliability analysis, structural equation model analysis, multiple group analysis of the collected data was made by utilizing SPSS 21.0 and AMOS 22.0. The results of study can be summarized as follows. First, it was shown that intrinsic satisfaction, sub-factor of intrinsic extrinsic job satisfaction, had a positive (+) effect on altruism. Second, it was shown that intrinsic satisfaction had a positive (+) effect on conscientiousness. Third, it was shown that intrinsic satisfaction had a positive (+) effect on participation. Fourth, it was shown that extrinsic satisfaction didn't have significant effect on altruism. Fifth, it was shown that extrinsic satisfaction didn't have significant effect on conscientiousness. Sixth, it was shown that extrinsic satisfaction didn't have significant effect on participation. Seventh, it was shown that skill variety had a moderation effect on the relationship which intrinsic satisfaction had with altruism and participation. Eighth, it was shown that task identify had a moderation effect on the relationship which intrinsic satisfaction had with altruism and participation. Ninth, it was shown that task significance had a moderation effect on the relationship which intrinsic satisfaction had with altruism, conscientiousness and participation.

• Journal of the Korean Society of Radiology
• /
• v.14 no.4
• /
• pp.345-351
• /
• 2020

In this study, a dose assessment was conducted on the exposure dose of thyroid, breast and sexual gland using a personal dosimeter in multiple CT examinations currently being conducted in health examinations. The dose assessment was measured by attaching TLD and EPD to the locations of the thyroid, breast and sexual gland during CT examinations of Brain, Brain + C-S, Brain + Low lung, Brain + L-S among CT items. The generated dose of equipment, CTDI_vol and DLP, was measured. The study found that effective doses were rated 41.7% higher for thyroid TLD in Brain + C-S CT examinations than for the general public, 156% higher for EPD, 10% for breast EPD in Brain + Low Lung CT examinations, 124.4% higher for reproductive TLD and 339.8% higher for Brain + L-S CT examinations. The CTDI_vol and DLP analysis results showed that C-S CTDI_vol values were higher than the diagnostic reference levels at 0.6%, Low Lung CTDI_vol values at 5.7%, DLP values at 11.8% and L-S CTDIvol values at 1.2%. In order to reduce the exposure dose of patients, indiscriminate examination is reduced and dose limit setting is needed in health examination.

• Smart Media Journal
• /
• v.12 no.2
• /
• pp.27-35
• /
• 2023

Currently, online user authentication is perform using joint certificates issued by accredited certification authorities and simple certificates issued by private agency. In such a PKI(Public Key Infrastructure) system, various cryptographic technologies are used, and in particular, digital signatures are used as a core technology. The digital signature scheme is equally used in DID(Decentralized Identity), which is attracting attention to replace the existing centralized system. As such, the digital signature-based user authentication used in current online services is also applied in the metaverse, which is attracting attention as the next-generation online world. Metaverse, a compound word of "meta," which means virtual and transcendent, and "universe," means a virtual world that includes the existing online world. Due to various developments of the metaverse, it is expted that new authentication technologies including biometric authentication will be used, but existing authentication technologies are still being used. Therefore, in this study, we study digital signature scheme that can be efficiently used for user authentication in the developing metaverse. In particular, we experimentally analyze the effectiveness of ECDSA, which is currently used as a standard for digital signatures, and Schnorr signatures, which can quickly verify a large amount of signatures.