• Journal of electromagnetic engineering and science
• /
• v.4 no.2
• /
• pp.51-55
• /
• 2004

With the progress of the electronics industry and radio communication technology, certain problems, such as electromagnetic interference(EMI), have arisen due to the increased use of electromagnetic(EM) waves. International organizations such as CISPR, FCC, and ANSI have provided the standards for the EM wave environment and for the countermeasure of the electromagnetic compatibility(EMC). EM wave absorbers are used for constructing an anechoic chamber to test and measure EMI and electromagnetic susceptibility(EMS). In this paper, we have designed an one-body EM(electromagnetic) wave ferrite absorber, based on the equivalent material constants method for both normally and obliquely incident waves, whose absorption abilities are superior to that of the conventional ones. The fabricated absorber has a thickness of 27.68 mm and shows an absorption ability over 20 ㏈ in the frequency from 30 MHz to 6 ㎓.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2004.05a
• /
• pp.370-373
• /
• 2004

The inside and outside of the country utilities considered that they focused energy and economic aspect for short-term in new environment change of restructure. but it need service reliability preservation and improvement countermeasure, that is no to use existent estimation method for reliability preservation. therefore, analyze the equipment failure rate for suitable reliability preservation through equipment failure rate analysis of power distribution r system and evaluated equipment that is composing power distribution system by the failure rate. This paper estimated failure causes and the TVFR(Time Varying Failure Rate) for main equipment that is composing power distribution system using Weibull distribution.

• Proceedings of the KAIS Fall Conference
• /
• 2006.11a
• /
• pp.176-179
• /
• 2006

We are using COS to purpose blocking the excess current and to protect the transformer. But the fuse of COS is melt due to the overload if the excess current flows and it destroy an air severing relations to clear as strong arc happens. Such phenomenon induces an impact ambient noise and it gives the circumstance area resident or pedestrian the fear. Thus, We are the actual circumstances which an ambient noise countermeasure establishment have desired urgently. In this study, we grasp the characteristic of an impact ambient noise which a COS fuse happens the melting and study the method to reduce an impact ambient noise.

• 한국방재학회:학술대회논문집
• /
• 2008.02a
• /
• pp.661-664
• /
• 2008

U-Eco City is promoted nation-wide by development of recent IT technology, method of effective countermeasure disasters, which real-time wire/wireless communication network, and 3D-Web GIS shall be connected that massive database, intelligent service be perceived. U&V-City is the four-dimensional future city that actualizes an intelligent daily ubiquitous computing service by embodying 3D-Virtual City, the reproduction of real world U-City while using Digital map, satellite image, VRML(Virtual Reality Modeling Language), which are presentation tool to describe city components and by efficiently catch and cope about nature and human disasters while employing EAI(External Authoring Interface) that provides HTML&JAVA, and interface for efficient removal/process of massive information/service and also by employing GPS/LBS/Navigation in support of the world-wide orientation concept, and RTLS(Real Time Location System).

• Journal of KSNVE
• /
• v.10 no.1
• /
• pp.107-116
• /
• 2000

The gear whine noise caused by tooth profile, elastic deformation, machining error, wear is directly correlated with the transmission error of mating gear. It is very important to build up the synthesized countermeasure by the modeling of the excitation forces and analyzing the vibratory characteristics. The mathematical models on the elements of vehicle transmission which is composed of helical gears, bearings, shafts and cases are developed. The elements are assembled by the substructure synthesis method. The cases of transmission are modeled by ANSYS. The system model of vehicle transmission is also verified by the experiments.

• Journal of the Korean Society of Industry Convergence
• /
• v.21 no.6
• /
• pp.317-327
• /
• 2018

The perception of earthquake in Korea has changed due to the earthquake that occurred in Gyeongju and Pohang, and the earthquake has become an important factor in infrastructure management. Damage to infrastructures in the event of an earthquake is extensive. In particular, damage to infrastructures that perform public function used to spread to the whole area. From the point of view of earthquake disaster prevention, it is very important for the public to define what infrastructures are important management targets and to prepare a countermeasure. In this study, we propose a method to evaluate the importance of infrastructure to effectively manage infrastructures for earthquakes. For this purpose, important factors for the railway bridges, power generation and electric power facilities, and apartment complexes are suggested. AHP analysis is conducted to suggest priorities. In addition, the evaluation criteria for infrastructure importance are presented.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.12
• /
• pp.1577-1586
• /
• 2018

The emergence of the Smart Grid is an integrated solution for the next generation power system that combines IT technology in the power system to create optimal energy utilization and various services. However, these convergence technologies (power systems and information communications) are not only improving the related technologies but also producing various problems especially exposure to cyber risk. In particular, the intelligent power grid has security vulnerabilities through real-time information sharing among various organically linked systems, and it is more complicated than the cyber risk problem in the existing IT field and is directly connected to national disaster accidents. Therefore, in order to construct and operate a more stable smart grid, this paper analyzes the system of power system control system in Korea, and proposes a cyber security element definition and a countermeasure establishment method of power monitoring & control systems based on security standards of smart grid (No. SPS-SGSF-121-1-1).

• Journal of Korea Multimedia Society
• /
• v.21 no.12
• /
• pp.1448-1458
• /
• 2018

Vehicular Ad-Hoc Networks (VANETs) have become one of the active areas of research, standardization, and development because they have tremendous potentials to improve vehicle and road safety, traffic efficiency, and convenience as well as comfort to both drivers and passengers. However, message trustfulness is a challenge because the propagation of false message by malicious vehicles induces unreliable and ineffectiveness of VANETs, Therefore, we need a reliable reputation method to ensure message trustfulness. In this paper, we consider a vulnerability against the Sybil attack of the previous reputation systems based on blockchain and suggest a new reputation system which resists against Sybil attack on the previous system. We propose an initial authentication process as a countermeasure against a Sybil attack and provide a reliable reputation with a cooperative message delivery to cope with message omission. In addition, we use Homomorphic Commitment to protect the privacy breaches in VANETs environment.

• Journal of the Korea Society of Computer and Information
• /
• v.24 no.4
• /
• pp.65-71
• /
• 2019

IAs smart device penetration rate is more than 90%, mobile transaction ratio using smart device is increasing. Smart contracts are used in various areas of real life including smart trading. By applying smart contracts to the platform for smart transactions through block-chain technology, the threat of hacking or forgery can be reduced. However, various threats to devices in smart transactions can pose a threat to the use of block chain Etherium, an important element in privilege and personal information management. Smart contract used in block chain Ethereum includes important information or transaction details of users. Therefore, in case of an attack of privilege elevation, it is very likely to exploit transaction details or forge or tamper with personal information inquiry. In this paper, we propose a detection and countermeasure method for privilege escalation attack, which is especially important for block chain for secure smart transaction using block chain Ethereum. When comparing the results of this study with the results of similar applications and researches, we showed about 12~13% improvement in performance and suggested the future countermeasures through packet analysis.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.6
• /
• pp.29-35
• /
• 2005

This paper presents the basic quench protection idea for the HTS(High-Temperature Superconducting) cable. In Korea power system, the transfer capability of transmission line is limited by the voltage stability, HTS cable could be one of the countermeasure to enhance the transfer limit with its higher current capacity and lower impedance[1]. However, the quench characteristic makes not only HTS cable to loss its superconductivity, but also change the impedance of the transmission line and power system operating condition dramatically. This pheonominum threats HTS cable safety as well as power system security, therefore a proper protection scheme and security control counterplan have to be established before HTS cable implementation. In this paper, the quench characteristics of HTS cable for the fault current based on heat balance equation was established and a proper protection method regarding conventional protection system was suggested.