• The KIPS Transactions:PartC
• /
• v.12C no.4 s.100
• /
• pp.597-602
• /
• 2005

In this study, file size for measurement and the service system's billing data were submitted to a comparative analysis by performing a verification test on the billing system of three major mobile communication services providers, based on the wireless Internet service packet. As shown in the result of the verification test, there were some differences in the billing data due to transmission overhead, according to the network quality that is affected by the wireless environment of mobile operators. Consequently, the packet analysis system was proposed as a means of applying consistent packet billing to all service providers being compared. If the packet analysis system is added to supplement the current billing system various user requirements can be met. Billing by Packet among mobile operators and differentiated billing based on the content value are available, since the packet data can be extracted through protocol analysis by service, and it can be classified by content tape through traffic data analysis. Furthermore, customer's needs can be satisfied who request more information on the detailed usage, and more flexible and diverse billing policies can be supported like application of charging conditions to the non-charging packet handling. All these services are expected to contribute to the popularization of the wireless Internet service, since user complaints about the service charge could be reduced.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.23 no.7
• /
• pp.164-171
• /
• 2019

Focusing on the bridge facilities, which occupy the largest proportion among SOC public facilities in Korea, it is possible to reduce the cost compared to existing wired measurement systems or wireless measurement systems developed by domestic telecommunications companies, and to increase the technical perfection to be applied to many bridges. We developed a wireless measurement system for bridges. Using LoRa, one of the unlicensed LPWAN technologies, we have developed an optimized MEMS-based LoRa smart sensor node considering the domestic ISM band and the existing wired sensor LoRa DAQ sensor node that can communicate with the LoRa network. Application server was developed for the test bed performance verification and efficient management of the developed sensor node.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.3
• /
• pp.57-67
• /
• 2021

A thorough administration of the arterial road network requires a continuous supply of updated and accurate information about the traffic that travels on the roads. One of the ways to effectively obtain the traffic volume and weight distribution of heavy vehicles is the BWIM technique, which is actively being studied. Unlike previous studies, this study was performed to develop a simplified Bridge Weigh-In-Motion (BWIM) algorithm that can easily estimate the axle spacing and weight of a traveling vehicle by utilizing the structural characteristics of the bridge. A short span RC T-beam bridge with no crossbeam installed was selected for the study, and then the strain response characteristics of bridge deck and girder was checked through preliminary field test. Based on the preliminary field test results, a simplified BWIM algorithm suitable for the bridge to be studied was derived. The validity and accuracy of the BWIM algorithm derived in this study were verified through field test. As a result of the verification test, the proposed BWIM algorithm can estimate the axle spacing and gross weight of the travelling vehicles with the average percent error of less than 3%.

• Korean Security Journal
• /
• no.42
• /
• pp.7-36
• /
• 2015

This study aims at analyzing difference of social Security network, Community unity and local government trust according to socio-demographical features, exploring the relation of social Security network, Community unity and local government trust according to socio-demographical features, presenting results between each variable as a model and verifying the property of mutual ones. This study sampled general citizens in Gwangju for about 15 days Aug. 15 through Aug. 30, 2014, distributed total 450 copies using cluster random sampling, gathered 438 persons, 412 persons of whom were used for analysis. This study verified the validity and credibility of the questionnaire through an experts' meeting, preliminary test, factor analysis and credibility analysis. The credibility of questionnaire was ${\alpha}=.809{\sim}{\alpha}=.890$. The inout data were analyzed by study purpose using SPSSWIN 18.0, as statistical techniques, factor analysis, credibility analysis, correlation analysis, independent sample t verification, ANOVA, multi-regression analysis, path analysis etc. were used. the findings obtained through the above study methods are as follows. First, building a social Security network has an effect on Community institution. That is, the more activated a, the higher awareness on institution. the more activated street CCTV facilities, anti-crime design, local government Security education, the higher the stability. Second, building a social Security network has an effect on trust of local government. That is, the activated local autonomous anti-crime activity, anti-crime design. local government's Security education, police public oder service, the more increased trust of policy, service management, busines performance. Third, Community unity has an effect on trust of local government. That is, the better Community institution is achieved, the higher trust of policy. Also the stabler Community institution, the higher trust of business performance. Fourth, building a social Security network has a direct or indirect effect on Community unity and local government trust. That is, social Security network has a direct effect on trust of local government, but it has a higher effect through Community unity of parameter. Such results showed that Community unity in Gwangju Region is an important factor, which means it is an important variable mediating building a social Security network and trust of local government. To win trust of local residents, we need to prepare for various cultural events and active communication space and build a social Security network for uniting them.

• The Journal of the Korea Contents Association
• /
• v.14 no.6
• /
• pp.108-118
• /
• 2014

The purpose of this study is to develop a relationship of measuring method for the social security network and verify its validity and reliability and apply it to investigate the due to security life satisfaction. This study is based by setting general residents of Seoul in 2013 and using the stratified cluster random sampling method to analyze a total amount of 203 examples. The measuring methods for the social security network was developed through document research, conceptual definition and drafting the survey, experts' conference, preliminary inspection and original examination, verification of the validity and reliability of the survey. An experts' conference took pace to verify the validity of the survey, and 6 factors were extracted through exploratory factor analysis crime prevention design, street CCTV facilities, volunteer neighborhood patrol, local government security education, police public peace service, private security service. The conclusion are the following. Collected data was analyzed based on the aim of this study using SPSSWIN 18.0, and practice frequency analysis, F test, factor analysis, reliability analysis, correlation analysis, multiple regression analysis. First, the validity of the social security network measurement is very high. Thus, the factors constituting the social security network were found to be crime prevention design, street CCTV facilities, volunteer neighborhood patrol, local government security education, police public peace services, and private security services, and the crime prevention design factor was found to be most explanatory. Second, the reliability of the social security network measurement is very high. Thus, the correlation between the questions and the sector, the questions and the social security net was very high, and the internal consistency showed a Cronbach's${\alpha}$ value of over 0.865. Third, the establishment of a social security network had the biggest effect on people in their forties. Thus, when the crime prevention design, street CCTV facilities, local government security education, police public peace services are systematically established, the social anxiety of citizens was reduced.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.7
• /
• pp.902-909
• /
• 2023

This study evaluated the performance test of a small-sized LTE-Maritime(LTE-M) transceiver that was developed and promoted to expand the use of intelligent maritime traf ic information services led by the Ministry of Oceans and Fisheries with the aim of supporting the prevention of maritime accidents. Accoriding to statistics, approximately 30% of all marine accidents in Korean water occur with ships weighing less than 3 tons. Therefore, the blind spots of maritime safety must be supplemented through the development of small-sized transceivers. The small transceiver may be used in fishing boats that are active near coastal waters and in water leisure equipment near the coastline. Therefore, verifying whether sufficient performance and stable communication quality are provided is necessary, considering the environment of their real usage. In this study, we reviewed the communication quality goals of the LTE-M network and the performance requirements of small-sized transceivers suggested by the Ministry of Oceans and Fisheries, and proposed a test plan to appropriately evaluate the performance of small-sized transceivers. The validity of the proposed test method was verified for six real-sea areas with a high frequency of marine accidents. Consequently, the downlink and uplink transmission speeds of the small-sized LTE-M transceiver showed performances of 9 Mbps or more and 3 Mbps or more, respectively. In addition, using the coverage analysis system, coverage of more than 95% and 100% were confirmed in the intensive management zone (0-30 km) and interesting zone (30-50 km), respectively. The performance evaluation method and test results proposed in this paper are expected to be used as reference materials for verifying the performance of transceivers, contributing to the spread of government-promoted e-navigation services and small-sized transceivers.

• Journal of the Korean Electrochemical Society
• /
• v.14 no.4
• /
• pp.253-260
• /
• 2011

In this study, computational simulation was performed for thermal management of modules consisting of 10 batteries. Simplified structure and equivalent thermal resistance network was applied to maintain the thermal properties. Verification test of the mesh were in progress to ensure the reliability of 2.6 mm in the narrow gap between the battery, resulting in at least three divided mesh between the shape of the grid was required. Type of air from rear of the module, type of air from top of the module and type of air from bottom of the module were applied and effective cooling methods are discussed based on the location of fan and air intake of the modules. Maximum temperature and temperature differences of modules that directly affect the performance of the module were compared, and also behavior of the fluid was confirmed by comparing the air flow. The best maximum temperature is shown type of air from bottom of the module to $40.27^{\circ}C$ and type of air from top of the module shows smallest temperature difference $0.73^{\circ}C$.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2017.04a
• /
• pp.166-166
• /
• 2017

모돈의 건강 상태를 정량 지수화 하기 위한 연구를 수행 중이다. 지제이상, 섭식 불량, 수면 패턴 등의 운동 특성 분석을 위하여 복수의 초음파 센서를 이용하였다. 시계열 계측 신호를 분석하여 정량 지수화를 수행하는 과정에서 주파수 도메인 분석을 시도하였다. 이 과정에서 주파수 도메인의 분해능에 따른 편차 극복을 위한 비선형 모델링을 수행하였다. 또한 인접한 시계열 데이터 구간 간의 상관성 분석이 가능하면 대용량 데이터의 실시간 처리로 인한 지연 시간 극복 및 기대되는 예후에 대한 조기 진단이 가능할 것이다. 본 연구에서는 구글에서 제공하는 Tensorflow와 NVIDIA에서 제공하는 CUDA 엔진을 동시 적용한 심층 학습 시스템을 이용하였다. 전 처리를 위하여 주파수 분해능 (2분, 3분, 5분, 7분, 11분, 13분, 17분, 19분)에 따른 데이터 집합을 1단계로 두고, 상위 10 순위 안에 드는 파워 스펙트럼 밀도의 크기를 2단계로 하여, 총 2~10개의 입력 노드를 순차적으로 선정하였고, 동일한 방식으로 인접한 시계열의 파워 스펙터럼 밀도를 순위를 변화시켜 지정하였다. 대표적인 심층학습 모델인 Softmax regression with a multilayer convolutional network를 이용하여 Recursive feature selection 경우의 수를 $8{\times}9{\times}9$로 총 648 가지 선정하고, Epoch는 10,000회로 지정하였다. Calibration 모델링의 경우 Cost function이 10% 이하인 경우 해당 경우의 학습을 중단하였으며, 모델 간 상호 교차 검증을 수행하기 위하여 $_8C_2{\times}_8C_2{\times}_8C_2$ 경우의 수에 대한 Verification test를 수행하였다. Calibration 과정 상 모든 경우에 대하여 10% 이하의 Cost function 값을 보였으나, 검증 테스트 과정에서 모든 경우에 대하여 $r^2$ < 0.5 인 결정 계수 값이 나타났다. 단적으로 심층학습 모델의 과도한 적합(Over fitting) 방식의 한계를 보인 것이라 판단할 수 있다. 적합한 Feature selection 및 심층 학습 모델에 대한 지속적이고 추가적인 고려를 통해 과도적합을 해소함과 동시에 실효적이고 활용 가능한 Classification을 위한 입, 출력 노드 단의 전후 Indexing, Quantization에 대한 고려가 필요할 것이다. 이를 통해 모돈 생체 정보 정량화를 위한 지능형 현장 진단 기술 연구를 지속할 것이다.

• The Journal of the Korea Contents Association
• /
• v.17 no.10
• /
• pp.1-8
• /
• 2017

As the recent advancement of military equipment has been accelerated, it is becoming more important to act as an inspection device that verifies the performance of equipment in real time. Most of the inspection equipments were developed on the Windows OS based system. considering development convenience and development period. However, sice the data communication between these models occurs asynchronously, there is a problem that it is difficult to guarantee real-time performance of the window-based inspection equiment. To solve these problems, we use real-time commercial solutions to guarantee the real-time performance of Windows-based inspection equipment. In this paper, we propose a method of designing and implementing the inspection equipment software based on Real-Time implanted Kernel-Multi Processor (RTiK-MP) operating in Windows environment. In addition, real-time performance data accuracy was measured through a high-speed communication tool and interlocking test to verify the performance of the inspection device based on the real-time porting kernel.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.46 no.5
• /
• pp.44-51
• /
• 2009

In this paper, an air conditioner peak power control system using electric power line communication has been developed. The air conditioner power control system using RS-485 communication method is hard to install on the existing buildings due to difficulty in cabling, and the system using wireless communication methods has a weak point of not being able to be used in close space, while the developed system has its own advantages of overcoming the above mentioned obstacles. In addition, the system is extended to support not only single-phase electricity system but also three-phase four-wire electricity system, and therefore can be installed anywhere in the domestic environment. The system also has enhanced the ease of deployment, operational stability and economical efficiency by compact circuit design. Considering the current state requiring the energy sayings, the system would greatly contribute to the widespread use of the air conditioner power control system. The superiority in the performance and stability of the system has been proved by the design verification of each component such as remote air conditioner controller, electric power line gateway and so on, and the field test of the whole system.