• Journal of Korea Society of Digital Industry and Information Management
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• v.4 no.2
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• pp.29-37
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• 2008

Clustering allows hierarchical structures to be built on the nodes and enables more efficient use of scarce resources, such as frequency spectrum, bandwidth, and energy in wireless sensor networks (WSNs). This paper proposes a hierarchical clustering algorithm called EEHC which is more energy efficient than existing algorithms for WSNs, It introduces region node selection as well as cluster head election based on the residual battery capacity of nodes to reduce the costs of managing sensor nodes and of the communication among them. The role of cluster heads or region nodes is rotated among nodes to achieve load balancing and extend the lifetime of every individual sensor node. To do this, EEHC clusters periodically to select cluster heads that are richer in residual energy level, compared to the other nodes, according to clustering policies from administrators. To prove the performance improvement of EEHC, the ns-2 simulator was used. The results show that it can reduce the energy and bandwidth consumption for organizing and managing WSNs comparing it with existing algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9B
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• pp.1518-1526
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• 2000

This paper proposes an optical transmission link design method based on an optimum compensation scheme using dispersion compensating fiber (DCF), so that high-speed long-distance optical transmission would be possible over the conventional standard single mode fiber (SMF) link. The proposed design method provides the maximized transmission distances according to the signal speeds, where the amplifier spacing and repeater spacing are optimized wit respect to self-phase modulation(SPM) due to fiber nonlinearity and amplified spontaneous emission (ASE) noises caused by optical amplifies. It is also shown that there exists an optimum input signal power range balancing the effects of ASE noise and SPM for the given amplifier spacing and repeater spacing.

• Journal of muscle and joint health
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• v.27 no.1
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• pp.50-60
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• 2020

Purpose: This study aimed to identify the effects of preceptor's leadership, preceptor-preceptee exchange relationship, and preceptee's self-leadership on newly hired nurses' turnover intention. Methods: Participants were 175 nurses working at general hospitals in D city. Data were collected from 164 nurses in May 2019 and were analyzed using multiple linear regression with SPSS/WIN 24.0 program. Results: Newly hired nurses' turnover intention was negatively correlated with preceptor's transactional leadership (r=-.23, p=.003), preceptor's emotional leadership (r=-.28, p<.001), preceptor-preceptee exchange relationship (r=-.34, p<.001), and preceptee's self-leadership (r=-.23, p=.004). The work unit (β=.35, p<.001), preceptor-preceptee exchange relationship (β=-.28, p=.002), present work experience (β=.27, p=.043), and marital status (β=-.19, p=.009) were significant predictors of the turnover intention (R²=.26, p<.001). Conclusion: Therefore, in order to reduce the degree of turnover of new nurses, improving the exchange relationship of preceptor-preceptee is required, and balancing between work and life should be considered especially for the married new nurses.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3A
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• pp.217-224
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• 2010

In this paper, we propose a hard handover algorithm for a base station's self-optimization, one of the automatic operational technologies for the 3GPP LTE systems. The proposed algorithm simultaneously considers a mixed target sell selection method for optimal selection and a multiple parameter based active hysteresis method with the received signal strength from adjacent cells and the cell load information of the candidate target cells from information exchanges between eNBs through X2 interface. The active hysteresis method chooses optimal handover hysteresis value considering the costs of the various environmental parameters effect to handover performance. The algorithm works on the optimal target cell and the hysteresis value selections for a base station's automatic operational optimization of the LTE system with the gathered informaton effects to the handover performance. The simulation results show distinguished handover performances in terms of the most important performance indexes of handover, handover failure rate and load balancing.

• Smart Structures and Systems
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• v.17 no.6
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• pp.957-980
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• 2016

Structural damage detection (SDD) is a challenging task in the field of structural health monitoring (SHM). As an exploring attempt to the SDD problem, a hybrid self-adaptive Firefly-Nelder-Mead (SA-FNM) algorithm is proposed for the SDD problem in this study. First of all, the basic principle of firefly algorithm (FA) is introduced. The Nelder-Mead (NM) algorithm is incorporated into FA for improving the local searching ability. A new strategy for exchanging the information in the firefly group is introduced into the SA-FNM for reducing the computation cost. A random walk strategy for the best firefly and a self-adaptive control strategy of three key parameters, such as light absorption, randomization parameter and critical distance, are proposed for preferably balancing the exploitation and exploration ability of the SA-FNM. The computing performance of the SA-FNM is evaluated and compared with the basic FA by three benchmark functions. Secondly, the SDD problem is mathematically converted into a constrained optimization problem, which is then hopefully solved by the SA-FNM algorithm. A multi-step method is proposed for finding the minimum fitness with a big probability. In order to assess the accuracy and the feasibility of the proposed method, a two-storey rigid frame structure without considering the finite element model (FEM) error and a steel beam with considering the model error are taken examples for numerical simulations. Finally, a series of experimental studies on damage detection of a steel beam with four damage patterns are performed in laboratory. The illustrated results show that the proposed method can accurately identify the structural damage. Some valuable conclusions are made and related issues are discussed as well.

• CELLMED
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• v.8 no.1
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• pp.1.1-1.4
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• 2018

We have various understandings regarding health. Various medical systems being practiced in India other than conventional medicine i.e. Ayurveda, Yoga & Naturopathy, Unani, Siddha and Homoeopathy have defined health in their own way. From physical level up to spiritual level health has so many aspects which affect our overall personality. Some says that one who is established in self is healthy but some other says that in a perfect state of health physical homeostasis and mental equanimity occur in a balanced and healthy harmony. Another concept believes that health is normal and harmonious vibration of the elements and forces composing the human entity on the physical, mental, moral and spiritual planes of living in accordance with the constructive principles in Nature. At one place it is stated that good health means existence in harmony with evolution. The authors have reviewed various concepts and definitions of health and trying to conclude that health is a feeling which may be experienced only if you are really healthy. So, health is more and more balancing of all elements of your life in harmony with the universe.

• KSBB Journal
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• v.26 no.3
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• pp.183-188
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• 2011

Adult stem cells, which have characteristic of self-renewal and multipotency, are specialized cell types, responsible for the tissue regeneration of the damaged tissue. Recent studies suggest that stem cells senescence (or stem cells' ageing) is closely associated with the variety of ageing-related phenotypes such as tissue atrophy, degenerative diseases and onset of cancers. During ageing, declining of stem cells function and subsequently occurring mal-differentiation of stem cells would be important to understand the biological process of development of ageing-related phenotypes such as tissue degenerations and cancers. This review focuses on the DNA damage stress as a cause of senescence of stem cells and their mal differentiation, which is closely link to defect of regeneration potentials and neoplastic transformation. Understanding of molecular mechanisms governingsuch events is likely to have important implications for developing novel avenues for balancing tissue homeostasis longer period of time, further leading to 'Healthy ageing'.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.147_148
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• 2009

본 연구에서는 기존 중앙제어방식의 고장구간 분리 및 복구 시 문제점을 해소하기 위해 새로운 시도로서 고장이 완전히 분리된 상태에서 자율적 복구 알고리즘을 제안하였다. 제안된 방법론에서 무전압을 경험하는 FRTU들은 분하분할을 시도하고, 각 연계 개폐기 FRTU들은 자기의 부하융통 영역들을 동시에 자율적, 순차적으로 결정하도록 함으로서 전전시간을 최소화함은 물론, 합리적인 범위 내에서 부하분담 균등화가 얻어지도록 설계하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.1321-1332
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• 2016

Wireless sensor networks (WSN) are self-organized networks that typically consist of thousands of low-cost, low-powered sensor nodes. The reliability and availability of WSNs can be affected by faults, including those from radio interference, battery exhaustion, hardware and software failures, communication link errors, malicious attacks, and so on. Thus, we propose a novel multi-agent fault tolerant system for wireless sensor networks. Since a major requirement of WSNs is to reduce energy consumption, we use multi-agent and mobile agent configurations to manage WSNs that provide energy-efficient services. Mobile agent architecture have inherent advantages in that they provide energy awareness, scalability, reliability, and extensibility. Our multi-agent system consists of a resource manager, a fault tolerance manager and a load balancing manager, and we also propose fault-tolerant protocols that use multi-agent and mobile agent setups.

• IE interfaces
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• v.21 no.3
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• pp.333-342
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• 2008

Warehouses form an important link in a supply chain network. Among a variety of activities in warehouses, order picking is the process of retrieving a number of items out of storage to meet customer orders. Today, as the transactions through direct sales are wide spread, warehouses often receive a large amount of small orders to be handled within tight time windows, which makes fast and efficient order picking more important than ever. This paper examines a new order picking method where the concept of bucket brigade (BB) is applied. Bucket brigade is a way of dynamically coordinating workers who progressively perform a set of operations along a flow line. In bucket brigades, a worker is not assigned his jobs in a static way. Each worker takes a job from his predecessor when he is free. We identify some considerations when bucket brigades are applied to order picking activities. A new BB picking protocol is presented to improve existing BB picking protocols. Through simulation experiments, the performance of BB order picking is evaluated under various logistics environments.