• Journal of Korea Society of Digital Industry and Information Management
• /
• v.6 no.4
• /
• pp.95-105
• /
• 2010

DNS(Domain Name System) is a huge distributed database that converts host name to IP address. We are expecting the importance of DNS is more increased because many Internet application services appear according to the continuous increase of Internet users and nearly all the Internet application services use DNS. To prevent the interruption of DNS service, DNS server is configured with primary DNS server and a secondary DNS server which takes the place of primary DNS server in case of the service interruption. But this scheme is difficult for providing DNS service constantly in case of DDoS attack, which brings about much network load or network problems in DNS server group. Therefore, This paper proposed the scheme to locally distribute load of DNS server, and the use of address system to group the distributed DNS servers. Also, it proposed the authentication scheme of the correspondent server in case the server is changed in DNS server group having grouping address. In this paper, it is shown that the prosed scheme guarantees the improved service reliability with maintaining the present service performance through the evaluation. Through this, we can expect the high improved DNS service can be provided in the Internet environment in the future.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.207-210
• /
• 2001

Electrical equipment for railway is always experiencing wear and degradation by mechanical, electrical and environmental stress in service and the fault or the accident of high voltage main circuit directly causes operation interruption. Particularly propulsion drive of high speed switching inverter takes the form of specific degradation mechanism such as fast rising transient surge, reflective overvoltage and harmonic stress, and it is known that it threatens the long life and the reliability of electrical equipment. In this paper, statistics of fault and accident on main electrical equipment for railway are presented and also insulation degradation mechanism, which governs end life of electrical device, is analyzed. Finally the method of fault respondence and reliability improvement on the main electrical equipments will be reviewed in order to prevent operation interruption.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.1
• /
• pp.124-129
• /
• 2005

Reliability of electric power supply by power system becomes major issue as the electric power industry is recently being regulated. Also a change of environmental condition related to power supply reliability should be considered in the view of power supplier since the competition between energy-industries is strengthen. In other words, because customers may choose other energy source instead of electric power due to an expensive energy charge, enhancing recklessly the reliability of power supply might not be an essential strategy. So to effectively cope with this problem, it is necessary to perceive the reaction of customers against power supply reliability and interruption cost. This paper evaluates the annual interruption costs of customers by regional groups in Korea using a macro approach to cope with these internal and external environment. That is, the each ratio of customer's interruption costs to price of electric power charge is evaluated for public, service, agricultural, fishery, mining, manufactural, and residential consumption by every cities and provinces.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.10B
• /
• pp.866-879
• /
• 2004

This paper presents a pricing model for maximizing a service provider's profit, taking into account consumers' quality-of-service dependent willingness to pay, in integrated voice/data mobile services. For the voice and the data services, time-sensitive pricing and volume-sensitive pricing mechanism will be applied, respectively, as in the case of Korea's mobile service market. Assuming that consumers are very sensitive to call interruption during handoff moments, the model presented here considers reserving guard channels exclusively for handoff traffic, in the process of frequency channels allocation, as well as guaranteeing consumers quality of service regarding call interruption rate. Ultimately, this model proposes a means to guarantee the quality of service in the short term, through pricing strategies as well as channel allocation policies, and the simulation results show that without expanding system resources, there exists a trade-off between profit and quality-of-service guarantee.

• 한국HCI학회:학술대회논문집
• /
• 2006.02b
• /
• pp.233-239
• /
• 2006

차세대 디지털 방송 기술인 DMB(Digital Multimedia Broadcasting) 지상파서비스가 세계최초로 우리나라에서 시작되었다. 현재 DMB 서비스는 디지털 기기의 다양한 기능들과 더불어 '디지털 컨버전스'를 주도하고 있고, 새 기술을 통한 서비스는 디지털 기기에 대한 사용자의 경험을 한층 풍부하게 해주고 있다. 또한 이러한 제품들은 다양한 기능에 대해서 멀티태스킹을 지원하기 때문에, 사용성, 조작방법 등 여러 측면에서 과거의 제품들과 상당히 많은 차이를 보여준다. 본 논문은 다양한 기능이 통합되고, 멀티태스킹이 되는 제품을 설계하는데 있어 감각양식(Modality) 측면에서 사용자들에게 더 나은 경험을 제공할 수 있도록 하는 방법을 제안한다. 지금까지 모달리티와 인터럽션(Interruption)에 대한 연구는 다중 자원 이론(Multiple resource theory)을 바탕으로 연속적인 과업(Task)를 수행함에 있어서 과업의 감각양식이 충돌할 경우, 사용자에게 인지적인 부담을 준다는 측면에서 이루어져 왔다. 그러나, 본 논문에서는 태스크를 수행함에 있어 멀티태스킹의 지원 여부에 따라서 과업의 감각양식이 다양한 순서를 가지고 사용자에게 인터럽션을 일으킬 때, 사용자의 태스크 수행 능력이나 사용자 만족도에 어떻게 영향을 주는지 알아보고자 한다.

• Journal of Korean Society of Water and Wastewater
• /
• v.27 no.1
• /
• pp.129-138
• /
• 2013

Water interruption is often caused by a rupture in the branch-like singular pipeline. This will cause critical complaints from household and may decrease public service quality. As an alternative of singular pipeline, additional parallel pipeline could be installed for sustainable water supply. This system is called double pipeline system and able to be utilized for water transmission line between treatment plant and distribution reservoir. Construction of double pipeline was thought to increase capital cost, which can be an issue to waterworks authorities. Reducing capital cost was possible by means of installing connectors between two parallel pipelines because of reduced diameter of each pipe. To obtain optimal design condition for connectors, it was necessary to compare water pressure according to accident location, to investigate flow according to connection pipe spacing, connection pipe diameter, and aging of pipe. Reliable and economical connection layouts were determined based on these results. The cost estimation for each design condition was carried out. Cost was approximately reduced by 20 ~ 30 % compared to the double pipeline without connections. In addition to this, connection between double pipelines could expect extra benefits for maintenance since the pipe could be repaired and rehabilitated without interruption.

• Journal of the Ergonomics Society of Korea
• /
• v.26 no.3
• /
• pp.67-80
• /
• 2007

Digital convergence, defined as the creative fusion of once-independent technologies and service, is getting more attention recently. Interruptions among internal functions happen frequently in digital convergence products because many functions that were in separate products are merged into a single product. Multi-tasking and multi-modality are two distinctive features of interruption in digital convergence products, but their impacts to the user have not been investigated yet. This study conducted a controlled experiment to investigate the impacts of multi-tasking and multi-modality on the subjective satisfaction and objective performance of digital convergent products. The study results indicate that multi-tasking and multi-modality have substantial effects individually as well as together. The paper ends with practical and theoretical implications of study results as well as research limits and future research.

• ETRI Journal
• /
• v.43 no.3
• /
• pp.447-458
• /
• 2021

The quality of experience (QoE) of video streaming is degraded by playback interruptions, which can be mitigated by the playout buffers of end users. To analyze the impact of playout buffer dynamics on the QoE of wireless adaptive hypertext transfer protocol (HTTP) progressive video, we model the playout buffer as a G/D/1 queue with an arbitrary packet arrival rate and deterministic service time. Because all video packets within a block must be available in the playout buffer before that block is decoded, playback interruption can occur even when the playout buffer is non-empty. We analyze the queue length evolution of the playout buffer using diffusion approximation. Closed-form expressions for user-perceived video quality are derived in terms of the buffering delay, playback duration, and interruption probability for an infinite buffer size, the packet loss probability and re-buffering probability for a finite buffer size. Simulation results verify our theoretical analysis and reveal that the impact of playout buffer dynamics on QoE is content dependent, which can contribute to the design of QoE-driven wireless adaptive HTTP progressive video management.

• Journal of Korean Society of Water and Wastewater
• /
• v.31 no.6
• /
• pp.511-519
• /
• 2017

Multi-regional water supply system, which installed for supplying multiple water demands, is characterized by large-sized, long-distance, tree-type layout. This system is vulnerable to long-standing service interruption when a pipe breaks is occurred. In this study, a numerical method is proposed to calculate drainage time that directly affects time of service interruption. To begin with, governing equations are formulated to embed the delayed drainage effect by the friction loss, and to resolve complicated connection of pipelines, which are derived from the continuity and energy equations. The nonlinear hydraulic equations are solved by using explicit time integration method and the Newton-Raphson method. The developed model is verified by comparing the result with analytical solution. Furthermore, the model's applicability is validated by the examples of pipelines in serial, in parallel, and complex layout. Finally, the model is utilized to suggest an appropriate actions to reduce the deviation of draining time in the C transmission line of the B multi-regional water supply system.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.19 no.3
• /
• pp.141-149
• /
• 2024

This paper proposes a configuration automation technique to minimize service interruption time in the event of a corporate network access layer switch failure. The automation is achieved without the need for a separate external system, as the network setting information is stored in a container inside the switch, enabling rapid recovery without requiring separate storage. This approach ensures the continuity of network services and demonstrates the efficiency of configuration automation. The proposed technique improves corporate network stability by providing a quick response in the event of a failure.