• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.6
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• pp.1133-1151
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• 2010

Energy balanced consumption routing is based on assumption that the nodes consume energy both in transmitting and receiving. Lopsided energy consumption is an intrinsic problem in low-cost sensor networks characterized by multihop routing and in many traffic overhead pattern networks, and this irregular energy dissipation can significantly reduce network lifetime. In this paper, we study the problem of maximizing network lifetime through balancing energy consumption for uniformly deployed low-cost sensor networks. We formulate the energy consumption balancing problem as an optimal balancing data transmitting problem by combining the ideas of corona cluster based network division and optimized transmitting state routing strategy together with data transmission. We propose a localized cluster based routing scheme that guarantees balanced energy consumption among clusters within each corona. We develop a new energy cluster based routing protocol called "OECR". We design an offline centralized algorithm with time complexity O (log n) (n is the number of clusters) to solve the transmitting data distribution problem aimed at energy balancing consumption among nodes in different cluster. An approach for computing the optimal number of clusters to maximize the network lifetime is also presented. Based on the mathematical model, an optimized energy cluster routing (OECR) is designed and the solution for extending OEDR to low-cost sensor networks is also presented. Simulation results demonstrate that the proposed routing scheme significantly outperforms conventional energy routing schemes in terms of network lifetime.

• ETRI Journal
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• v.44 no.1
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• pp.155-167
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• 2022

The Internet of Things (IoT) is a new paradigm that connects physical and virtual objects from various domains such as home automation, industrial processes, human health, and monitoring. IoT sensors receive information from their environment and forward it to their neighboring nodes. However, the large amounts of exchanged data are vulnerable to attacks that reduce the network performance. Most of the previous security methods for IoT have neglected the energy consumption of IoT, thereby affecting the performance and reducing the network lifetime. This paper presents a new multistep routing protocol based on cellular learning automata. The network lifetime is improved by a performance-based adaptive reward and fine parameters. Nodes can vote on the reliability of their neighbors, achieving network reliability and a reasonable level of security. Overall, the proposed method balances the security and reliability with the energy consumption of the network.

• Journal of Multimedia Information System
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• v.1 no.2
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• pp.101-110
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• 2014

The purpose of this research is to extend Ad-hoc network system lifetime with the proposed routing protocol which has considered hop lifetimes of the nodes while guaranteeing QoS in the establishment process of Ad-hoc network communication paths. Based on another power aware routing system that proposed in the advanced research [1], we are proposing an alternative power aware routing system in which nodes' hop lifetimes are compared in order to extend the lifetime of an Ad-hoc network system and delay factors have been considered for the assurance of QoS. The research of the routing protocol in this paper, which aims to maximize the system survival time considering power consumption status during the path searching in MANET and pursues the mechanism that controls hop delays for the same reason, can be applied to the study of WSN. The study concerning such phenomena is essential so that the proposed protocol has been simulated and verified with NS-2 in Linux system focusing on the lifetimes of the hops of the nodes. Commercialization of smart devices and arrival of the ubiquitous age has brought about the world where all the people and things are connected with networks. Since the proposed power aware method and the hop delay control mechanism used to find the adequate communication paths in MANET which mainly uses batteries or in WSN, they can largely contribute to the lifetime extension of the network system by reducing power consumptions when utilized for the communications attempts among soldiers during military operation, disaster areas, temporary events or exhibitions, mobile phone shadow areas, home networks, in-between vehicle communications and sense networks, etc. This paper presents the definitions and some advantages regarding the proposed outing protocol that sustain and extend the lifetime of the networks.

• Journal of Distribution Research
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• v.9 no.2
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• pp.29-43
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• 2004

This research analyzed multi-channel strategy from the viewpoint of the customer relationship management. We hypothesized that the purchase frequency, monetary, purchase quantity of the existing customers should have increased after they used multiple channels of a company for shopping, All the hypothesis were supported in an empirical test using the customer database of a Korean TV home-shopping company, The result showed that the multi-channel strategy can be used to increase the life-time value of existing customers. Still there were a lot of customers who insists using traditional channel, which calls for a new strategy inducing them to use multi- channel for shopping.

• Proceedings of the Korean Reliability Society Conference
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• 2004.07a
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• pp.303-311
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• 2004

This paper presents the reliability estimation of door hinge for home appliances, which consists of bushing and shaft. The predominant failure mechanism of bushing made of polyoxymethylene(POM) is brittle fracture due to decrease of strength caused by voids existing, and that of shaft made of acrylonitrile-butadiene-styrene(ABS) is creep due to plastic deformation caused by excessive temperature and lowering of glass transition temperature by absorbed moisture. Since the brittle fracture of bushing is overstress failure mechanism, the load-strength interference model is used to estimate the failure rate of it along with failure analysis. By the way, the creep of shaft is wearout failure mechanism, and an accelerated life test is then planned and implemented to estimate its lifetime. Through the technical review about failure mechanism, temperature and humidity are selected as accelerating variables. Assuming Weibull lifetime distribution and Eyring model, the life-stress relationship and acceleration factor, B$_{10}$ life and its lower bound with 90% confidence at worst case use condition are estimated by analyzing the accelerated life test data.a.

• Journal of The Korea Institute of Healthcare Architecture
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• v.19 no.2
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• pp.51-59
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• 2013

Purpose: At the moment, a lot of poor older people live in permanent rental housing in Korea. But many rental apartments are not suitable for elderly living because most of them have many problems related to the lack of accessibility and adaptability for older people with physical and mental disabilities. So it is necessary to upgrade the old permanent rental housing for convenience of elderly living. The purpose of this paper is to construct basic data for remodeling of worn out and small rental housing block in order to realize the concept of "Aging in Place". Methods: Questionnaires and interviews about elderly living have been conducted on 104 elderly who live in Suwon Wooman permanent rental apartment block which was constructed 21 years ago. From the collected data, dining pattern, inconvenient area, small area, satisfaction level on unit area and demand for unit expansion type have been analysed in order to find out the direction for remodeling of permanent rental apartment unit. Results: The problems of existing permanent rental apartment can be summarized into improper laundry space, small dining area, inconvenient bath and so on. According to the family size, the elderly resident has the different preference about the expansion type of his resident unit. Big families usually want to enlarge their living unit though they pay for additional monthly rental fee. Implications: Lifetime home concept adopting Universal Design has to be applied to the whole residential block especially to the social rental housing. And this concept had better be expanded to Lifetime neighbor design.

• Research in Community and Public Health Nursing
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• v.21 no.4
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• pp.502-511
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• 2010

Purpose: The purpose of this study was to investigate the influencing factors of influenza vaccination in the elderly participating in lifetime transitional health examination. Methods: This study was a secondary analysis of data collected from lifetime transitional health examination (for 66-year-old people) conducted by the National Health Insurance Corporation (NHIC) from January 1 to December 31, 2008. Questionnaires were received from NHIC to obtain information regarding gender, chronic diseases, health-related behaviors, and ADL. A total of 255,333 participants who responded all the questions in the questionnaire were included in the analysis. Collected data were analyzed by descriptive statistics, ${\chi}^2$ test, and multiple logistic regression. Results: The influenza vaccine coverage rate in 66-year-old people was 66.1%. The influenza vaccine coverage rate was higher in female elders and those with hypertension, diabetes, heart disease or past smoking, and lower in those with stroke, current smoking, drinking, no-exercise or ADL-dependency. Conclusion: Strategies for improving the influenza vaccination coverage rate in the elderly are needed. The strategies should give priority to the elderly with current smoking, drinking, and no-exercise, and home visiting programs are needed for the elderly with stroke and ADL-dependency.

• Journal of Applied Reliability
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• v.14 no.1
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• pp.21-28
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• 2014

This paper presents an accelerated life test to estimate the lifetime of thermoelectric module for home water purifier. Clamping force and thermal cycle are selected as accelerating variables through the technical review about failure mechanism. It is assumed that its lifetime follows weibull distribution. The relationship, acceleration factor, and BP life at design condition are estimated by analyzing the accelerated life test data.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.1
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• pp.44-49
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• 2021

Recently, infrared (IR) and near-infrared (NIR) light-emitting diodes (LEDs) were widely used for home medical applications owing to its low output power and wide exposed area for curing. For deep penetration of the light under the skin, multiple LEDs with wavelengths of 700~10,000 nm were located on a flexible printed circuit board. When multiple wavelengths of LEDs were soldered on a circuit board, the lifetime of LED module highly depends on LEDs with a short lifetime. The mean time to failure (MTTF) was able to calculate with the experimental results under high temperature and the Arrhenius model. The results of this study could help companies to approve the warranty of LED modules and its product.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.368-369
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• 2003

The recent development of InGaN-based white light emitting diodes (LEDs) has expanded their potential applications in areas such as white electric home appliances, backlight for mobile phone or notebook PC, and indoor lightings. In this lecture, recent researches related to the phosphors for LEDs applications and their luminescent properties were reviewed. PDPs are considered as the most potential flat panel displays with a large-screen size. Phosphors in PDPs directly affect the brightness and lifetime. So, many researchers have tried to improve the luminescence characteristics of the phosphors especially under vacuum ultraviolet (VUV) excitation. We overviewed recent research trends and conclusive achievements for the PDP phosphors.