• Proceedings of the KSR Conference
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• 2006.11b
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• pp.838-843
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• 2006

In our modern society, such electric facilities as lighting, elevators, water supplies, drainages, waste water treatments and landscape lighting are being more enlarged, diversified and technology-intensive owing to outstanding technological development, while they require reliable and safe electricity. On the other hand, as more electric energy is consumed with more complicated systems operated, any accident from a personal electric system is likely to have wider spreading effects. In particular, the electric receivers and transformers installed for such public facilities as subway stations require highest safety, reliability and economy, but such requirements tend to be less considered than such financial requirements as budget conditions, much less their safety and reliability. In such a circumstance, this study was aimed at suggesting some standards for safe, reliable and economic subway electric systems in terms of their scale, location and uses. Specifically, this study put forwards the ways to optimize and standardize the electric systems including receivers and transformers for subway stations in order to make them safer, more reliable and economic.

• Journal of Information Display
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• v.6 no.4
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• pp.35-39
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• 2005

In this paper, we investigate the oxide cathodes for the development of reliable electron sources. Poisoning in oxide cathodes is one of the serious problems in achieving reliable electron emission. In particular, early poisoning induces poor life performance as will be demonstrated herein. The survivability of electron emission sources is significantly improved by high doping of high-speed activator. The robust oxide cathodes with 0.17 % Mg operating at about 1,050 K are expected to work for very long times (>100,000 hours). We suggest that this key idea will contribute to solving the basic problems in oxide cathodes such as poisoning or ion bombardment for high power or high frequency applications of electron sources.

• KIEAE Journal
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• v.12 no.3
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• pp.69-75
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• 2012

Developing reliable measures of the environment is important to increase our understanding of the environmental effects on walking among seniors. As a preliminary study for developing an instrument for measuring walkability of seniors' environment, the purpose of this study are to identify important assessment indicators associated with seniors' walking and to test their reliability using inter-rater and intra-rater reliability methods. A set of assessment indicators was identified through literature review, and field studies by trained raters were conducted in three senior centers located in Seongnam area in order to test reliability of the audit tool. The results indicated high percent agreement for most indicators and overall 91.6% and 86.1% of items assessed had good or medium inter-rater and intra-rater reliability, respectively. The reliable assessment indicators would provide reliable data for use in community-based audits of built environment in relation to walking among older adults. The findings showed that the indicators of aesthetics had lower reliability compare to safety, convenience, and access. Rater training with various images would improve rater agreement while reduce rater bias.

• Journal of Communications and Networks
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• v.18 no.2
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• pp.246-260
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• 2016

A major challenge achieving scalable access control for a large number of subscribers in a public broadcast is to distribute key update messages reliably to all stateless receivers. However, in a public broadcast, the rekeying messages can be dropped or compromised during transmission over an insecure broadcast channel, or transmitted to receivers while they were off-line. In this study, we propose a novel group key management scheme. It features a mechanism to allow legitimate receivers to recover the current group key, even if they lose key update messages for long-term sessions. The scheme uses short hint messages and member computation. Performance analysis shows that the proposed scheme has the advantages of scalability and efficient rekeying compared to previous reliable group key distribution schemes. The proposed key management scheme targets a conditional access system in a media broadcast in which there is no feedback channel from receivers to the broadcasting station.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2741-2743
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• 2001

The railway signaling systems are computerized vital equipments for safety guarantee of train running. And also it is important to prepare the reliable communication link between signalling equipments. In this paper the review of signalling communication protocol used at current railway signalling is presented and basic line for reliable protocol structure is represented. And also the direction for our further study on these is discussed.

• Journal of the Korean Home Economics Association
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• v.38 no.4
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• pp.115-128
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• 2000

This study was conducted to examine the relation between parental social support and disciplinary practices for fathers and mothers of young children. Two hundred-twenty mothers and two hundred-twenty fathers completed measures of parental social support and child disciplinary practices. The analyses were conducted separately for the group of fathers and the group of mothers. Descriptive analysis, Cronbach'$\alpha$ correlations and t-tests were used to examine research Questions. The resets of this study were as follows: 1. Social supports of the provisions of guidance, reliable alliance, and attachment were higher for mothers than for fathers. On the other hand, social support of the reassurance of worth was higher for lathers then for mothers. 2. Social supports of the provisions of guidance and reliable alliance were higher for fathers of sons than for fathers of daughters. 3. Social supports of the reliable alliance and social integration were higher for fathers of higher income than for fathers of lower income. 4. For both fathers and mothers, the higher they perceived their social supports, the more they used effective parental disciplinary practices.

• 전기의세계
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• v.28 no.7
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• pp.60-66
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• 1979

In this paper we deal with a hardware redundency, using the replications of an original module to enhance the reliability of the system in view of static and dynamic redundancy. As results of the study the following facts have been proved that (1) if the mission time is small (T .neq. 0.5), the effect of spare modules cannot be expected significantly, (2) for the small mission time (0.1 .neq. T .neq. 0.3) the SPR system is more reliable than the other redundant systems. In addition to above facts, it is also proved that for the large mission time (T=1), the dynamic redundant system is more reliable than the static redundant system, and that the SR system is more reliable than the HR system in the dynamic redundant system.

• Journal of Communications and Networks
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• v.11 no.3
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• pp.306-317
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• 2009

We consider the problem of architecting a reliable content delivery system across an overlay network using TCP connections as the transport primitive. We first argue that natural designs based on store-and-forward principles that tightly couple TCP connections at intermediate end-systems impose fundamental performance limitations, such as dragging down all transfer rates in the system to the rate of the slowest receiver. In contrast, the ROMA architecture we propose incorporates the use of loosely coupled TCP connections together with fast forward error correction techniques to deliver a scalable solution that better accommodates a set of heterogeneous receivers. The methods we develop establish chains of TCP connections, whose expected performance we analyze through equation-based methods. We validate our analytical findings and evaluate the performance of our ROMA architecture using a prototype implementation via extensive Internet experimentation across the PlanetLab distributed testbed.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.1
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• pp.8-13
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• 2001

LMS algorithm has been used for plant identifier and noise cancellation. This algorithm has been researched for performance enhancement of filtering. The design and development of a reliable system has been becoming a key issue in industry field because the reliability of a system is considered as an important factor to perform the system's function successfully. And the computing with reliability and fault tolerance is a important factor in the case of aviation, system communication, and nuclear plant. This paper presents design of reliable adaptive filter with fault tolerance. Generally, redundancy is used for reliability. In this case it needs computing or circuit for voting mechanism, or fault detection. Therefore it has simple computing, and practicality for application. And in this paper, reliability of adaptive filter is analyzed. The effectiveness of the proposed adaptive filter is demonstrated to the case studies of plant identifier and noise cancellation by using DSP.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1020-1025
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• 2007

EMS(energy management system) and SCADA(supervisory control and data acquisition) systems are used for reliable and efficient operation of electrical power systems. Various functions in EMS such as power flow, contingency analysis, security analysis essentially need accurate data set for reliable operation. State estimation can be a tool for providing these data. In this paper, programs for observability analysis and bad data processing are developed. Fundamental algorithms are introduced and validity of the proposed techniques is inspected with test cases.