• The Journal of the Korea Contents Association
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• v.7 no.12
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• pp.273-282
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• 2007

The Domain Name System (DNS) is the core system for managing Internet address resources, providing the most fundamental naming service. Currently, the DNS is classified into a tree structure. In this structure, it is difficult to normally access to the lower DNS, when there is an error in the upper DNS. Such a risk still remains even when a supplementary DNS is operated. However, due to the merit of the DNS enabling fast searches, it is impracticable to abandon the current tree structure. To efficiently correspond to DNS errors, this study suggests a method where the merit of the current tree structure is kept, while a temporary operation of the local DNS is available when errors occur by adding a horizontal and independent DNS structure.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.539-542
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• 2006

본 논문은 IPv6 환경에서 보다 안전한 DNS 구성에 대해 제안한다. DNS 서버는 도메인 네임을 해당하는 IP 주소로 맵핑하여 주는 시스템으로 IPv6 환경에서는 늘어나는 IP 주소의 길이로 인해 직접적인 사용이 힘들고, 현재 거의 모든 인터넷 응용 서비스들이 DNS를 이용하고 있다는 점에서 앞으로 그 중요성은 더욱 높아질 전망이다. 현재 사용되고 있는 DNS 서버의 구성은 1차, 2차 서버를 통해 1차 서버의 장애 발생 시 그 역할을 2차 DNS가 수행하는 방식이다. 그러나 이는 DNS 서버가 속해 있는 네트워크를 대상으로 하는 공격이나 장애에 대응하기 어렵고, DNS 서버의 이용자 또한 서비스의 연속성을 보장받기 어렵다. 이를 해결하기 위해 본 논문은 Anycast 전송 기술을 DNS 서버에 적용하여 재구성함으로써 장애 발생 시에도 안정적으로 도메인 네임 서비스를 사용자에게 제공할 수 있는 방안을 제시하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.1
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• pp.90-100
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• 2013

Active-Standby Duplication Techniques are conventionally used for fault-tolerant systems. But in this paper we researched on the Active-Active Duplication Techniques for Fault-tolerant DNS System. Our Active-Active Duplication made the 1st DNS periodically copied to the 2nd DNS and maintained the same status by using Rsync and Crontab. Even though the 1st or the 2nd DNS stops due to some critical errors, the remaining DNS can take over and provide continuous services.

• Journal of The Korean Society of Emergency Medicine
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• v.29 no.5
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• pp.519-528
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• 2018

Objective: Delayed neuropsychiatric sequelae (DNS) following carbon monoxide (CO) poisoning, which may result from a demyelinating leukoencephalopathy, is a disease with a poor prognosis. This study examined the factors affecting the long-term prognosis of DNS and the efficacy of hyperbaric oxygen therapy (HBOT) in patients with DNS. Methods: This retrospective study included 84 patients with DNS following CO poisoning from January 2013 to June 2016. HBOT was given to 24 patients. The patients were divided into an improvement group and non-improvement group based on their clinical condition on a telephone interview at intervals between 3 months and 3 years after the onset of DNS. The improvement group was defined as having Cerebral Performance Category (CPC) scores in their daily life that improve to 1 or 2 grade. Results: Of the 594 patients, DNS were found in 18.2%, and 70.2% (59 of 84) of the patients with DNS improved. The prognostic factors for the improvement of DNS were an age of 45 years or less (odds ratio [OR], 12.068; 95% confidence interval [CI], 2.393-60.858; P<0.005), CPC score of 1 or 2 group at the time of DNS onset (OR, 12.361; 95% CI, 3.161-48.330; P<0.005), and a lucid interval longer than 20 days (OR, 5.164; 95% CI, 1.393-19.141; P<0.01). HBOT was not associated with the improvement of DNS in CO poisoning (OR, 0.467; 95% CI, 0.172-1.269; P>0.1). Conclusion: Patients aged less than 45 years, low grade CPC score of 1 and 2, and lucid interval longer than 20 days are more likely to have a good prognosis. On the other hand, HBOT failed to produce a benefit for DNS patients.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.07a
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• pp.89-90
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• 2023

본 논문에서는 HAProxy를 이용하여 웹 서버를 제어하는 모델을 제안한다. 인터넷이 다양한 분야로 확대됨과 다양한 디바이스의 활용으로 이용자 및 이용 시간, 이용 빈도가 증가하고 있다. 서버를 운영하는 과정에서 서비스 중간에 서버를 제외하고 투입해야 하는 상황들이 발생하고 있다. 이에 본 논문에서는 DNS에서 서버 IP를 투입 및 제외를 통해 이뤄지고 있는데, DNS 서버를 직접 운영하고 있지 않을 경우 처리시간이 증가한다는 불편한 점을 DNS 서버와 웹 서버 사이에 HAProxy 서버를 추가하여 웹 서비스 운영을 유연하게 처리하여 장애 등의 상황에서 빠르게 대처하여 웹 서비스를 사용하는 사용자의 불편함을 감소시킬 수 있을 것으로 기대할 수 있다.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.115-122
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• 2002

This paper presents a new web cluster scheme based on dispatcher which does not depend on operating system for server and can examine server's status interactively. Two principal functions are proposed for new web cluster technique. The one is self-controlled load distribution and the other is transaction fail-safe. Self-controlled load distribution function checks response time and status of servers periodically, then it decides where the traffic goes to guarantee rapid response for every query. Transaction fail-safe function can recover lost queries including broken transaction immediately from server errors. Proposed new web cluster scheme is implemented by C language on Unix operating system and compared with legacy web cluster products. On the comparison with broadcast based web cluster, proposed new web cluster results higher performance as more traffic comes. And on the comparison with a round-robin DNS based web cluster, it results similar performance at the case of traffic processing. But when the situation of one server crashed, proposed web cluster processed traffics more reliably without lost queries. So, new web cluster scheme Proposed on this dissertation can give alternative plan about highly increasing traffics and server load due to heavy traffics to build more reliable and utilized services.

• Journal of the Korea Society of Computer and Information
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• v.10 no.5 s.37
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• pp.151-160
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• 2005

High availability and business continuity in the mission critical enterprise environment have been a matter of primary concern. It is desirable to implement replicated servers, duplicated devices and disaster recovery sites so that these issues are accomplished. When that happens, web browser's users may be accessed web server through a specific Uniform Resource Locator. A critical issue arises if web browser's users recklessly change the URL and access into other site. In this case, data integrity between duplicated sites may not be guaranteed. In this paper, we introduce the method of integrating the technologies of user authentication, certificate authority and business continuity and Propose the design and implementation of intelligent service access management.

• The Transactions of the Korea Information Processing Society
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• v.5 no.7
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• pp.1855-1862
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• 1998

An Internet user obtains an IP address from DNS to access the host. But, Korean users must use English word order Domain that is not convenient for them. All existing systems have the reverse of the Korean word order and that is the obstacle to the spreading of Internet. So, the necessity of a Korean name system that well suited for Korean Internet user is increasing. In order to operate the proposed Korean Domain System with existing Domain Name Systems, we build a Korean to English transformation rule and Korean Domain Name composition rule. Also, we designed a STHOP for Korean word order processing. In a STROP, a SLDF transform a Korean SLD into English SLD, and a NFDNG makes this as an English word order. By using Korean Domain Name System proposed here, users could understand the embedded meaning of Domain Name with ease, and reluctance of Domain registration caused by similarity of organization names would be solved, Consequently. it could devote to the popularization of the Internet.