• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.7
• /
• pp.1032-1037
• /
• 2002

In this paper, derived monocycle pulse that application is possible within permission frequency band (3.1 ~ 10.6GHz) that establish in FCC. Also, PPM modulated TH IR system simulator is designed in AWGN environment. It is analyzed monocycle pulse specific property and system performance using simulator. Also, analyzed BER performances of IR system in multiple access interference environment using proposed parameters. According to result, application of possible pulse duration$(t_n)$ is very limited by 0.04~0.0326 ns in permission frequency range that establish in FCC. In the case of same pulse signal power, we could know that system performance changes by $N_s$ regardless of pulse duration. IR system that need high speed transmission more than 50 Mbps in multiple access interference environment could know that very serious performance decrease by multiple access Interference happens.

• Proceedings of the Safety Management and Science Conference
• /
• 2011.04a
• /
• pp.243-250
• /
• 2011

In this study, we examine the changes of the freight transport business penetration system and its classification through the theoretical study. By searching case studies of related systems in developed countries, this thesis derives problem and suggests improvement.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.1860-1871
• /
• 2011

Presently, The Regular Block System(Automatic, Interlocking block system) is usually used during the operation of block section. However, In case that the regular block system fails because of the failure of the fixed signals and block equipment or in case of the unexpected emergent situation which should drive on the single-track due to the accidents in the double-track section or the repair work of the one-track, the Substitute Block System to make use of the driving permission license(mapping ticket, mapping paper) is used. In case of the operation of the opposite line and the temporary one-track, the safety gets worse and the SBS may cause the fatal accidents such as a head-on & a rear-end collision. Also, the unmanned railroad stations has recently increased owing to the effective operation of the stations, for it is difficult to execute the SBS in their absence. As a result, the increase of the operation time made the train delayed. Being on the rise of these problems, in this study, we analyzed the problems and difficulties of the SBS on the single line which is lacking stability and safety and on the sections combined between maned and unmaned railroad stations. And we proposed the method to improve the existing drive permission license used for 50 years into the brand-new one with state-of-the art technology and scientific way. In the era of the 21th century, Carrying out the new SBS equipped with stability and safety, we will contribute to the effective operation of trains and the satisfaction of our customers in the future.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.16 no.3
• /
• pp.164-179
• /
• 2013

Ulaanbaatar city, the capital of Mongolia and the center of Mongolian economy, increasingly needs to have a long-term urban planning and a system to impose a tax on land effectively as insufficient development of land and the moving of nomad into urban areas increases during its rapid growth. Therefore, Mongolian government has to prepare a land management system which provides the infrastructure to improve work efficiency and service quality by integrating digitalized data about land and main facilities and sharing data between related departments. This research analyzed the environment to operate the existing land management system and working environment and redesigned database. Furthermore, it integrated all the existing systems, configured service network, and made working environment for land registration, land permission, land payment management to be processed online. With this, it provides the foundation to improve quality of people's life through the preparation of long term urban planning, clean tax administration of real estate, and reconsideration of efficiency about urban infrastructure investment.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.9 no.2
• /
• pp.83-92
• /
• 1999

Cryptography techniques can prevent eavesdroppers from maliciously intercepting or modifying sensitive information. however misuses of encryption may cause other problems First if the encryption key is lost or damaged even an authorized access to the original data will be denied. Second criminals can prevent authorized law enforcement officers from examining the necessary information by using the strong encrypted data can provide solutions for the situations. In this paper we propose a new key escrow system based on the ElGamal cryptosystem. Our system provide time-bound eavesdropping under court authorized permission protect from trustee's cheating and prevent user's shadow public key generation.

• Bulletin of the Korean Mathematical Society
• /
• v.53 no.4
• /
• pp.1051-1069
• /
• 2016

Combining the concept of self-certified public key and message recovery, Li-Zhang-Zhu (LZZ) gives the proxy signature scheme with message recovery using self-certified public key. The security of the proposed scheme is based on the discrete logarithm problem (DLP) and one-way hash function (OWHF). Their scheme accomplishes the tasks of public key verification, proxy signature verification, and message recovery in a logically single step. In addition, their scheme satisfies all properties of strong proxy signature and does not use secure channel in the communication between the original signer and the proxy signer. In this paper, it is shown that in their signature scheme a malicious signer can cheat the system authority (SA), by obtaining a proxy signature key without the permission of the original signer. At the same time malicious original signer can also cheat the SA, he can also obtain a proxy signature key without the permission of the proxy signer. An improved signature scheme is being proposed, which involves the remedial measures to get rid of security flaws of the LZZ et al.'s. The security and performance analysis shows that the proposed signature scheme is maintaining higher level of security, with little bit of computational complexity.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.5 no.2
• /
• pp.289-296
• /
• 2015

Java is an interpreted language that can run on a variety of platforms, also Java has a number of useful features for network. Due to theses features of Java language, Java is used in various fields. In this paper, we will talk about how the malware that threaten the Java Security Manager of the Java Virtual Machine is using the vulnerability of the Java Virtual Machine. And for corresponding measures, this paper suggest vulnerability analysis method of Java system class by using Java Call Graph and Java Access Permission Checking Tree. By suggesting that, we want to lay groundwork for preventing Java security threats in advance.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.11
• /
• pp.3011-3019
• /
• 1999

Denial of service is about knocking off services, without permission for example through crashing the whole system. This kind of attacks are easy to launch and it is hard to protect a system against them. The basic problem is that Unix assumes that users on the system or on other systems will be well behaved. This paper analyses system-based inside denial of services attack(DoS) and system metric for performance of each machine provided. And formalize the conclusions results in ways that clearly expose the performance impact of those observations. So, we present new approach. It is detecting DoS attack using performance signature for system and program behavior. We present new approach. It is detecting DoS attack using performance signature for system and program behavior. We believe that metric will be to guide to automated development of a program to detect the attack. As a results, we propose the AIDPS(Architecture for Intrusion Detection using Performance Signature) model to detect DoS attack using performance signature.

• The Journal of the Korean dental association
• /
• v.49 no.9
• /
• pp.511-518
• /
• 2011

Policy of for-profit hospitals permission has provoked debate on how to enhance health care system and medical service industry. The government says that for-profit hospitals could help improve the quality of medical care and develop medical tourism. On the other hand, Medical care related NGO insist that for-profit hospitals will not fix the existing medical problems in Korea, only create new ones. Recently, a type of for-profit hospitals emerged in dentistry and caused much trouble. Accordingly, We try to carefully look at for-profit hospitals related policy and debate.

• Proceedings of the KIEE Conference
• /
• 2006.07a
• /
• pp.541-542
• /
• 2006

The dispersed generation is recently increased introduction for the energy supply rationalization and effective management of power system. But the dispersed generation causes to the various trouble that isn't occurred in the past, for example, the two way systems have an effect on the mistake action of protection equipment and the power quality. In this paper, we research the influence on the harmonic when the dispersed generation is interconnected with distribution system. To achievement, we construct the interconnecting dispersed generation and distribution system which is applied to the permission of harmonic emission. After that, we simulate about the harmonic of distribution system interconnection dispersed generation by the PSCAD/EMTDC analyzing transient state of the power system.