• Convergence Security Journal
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• v.16 no.6_2
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• pp.83-88
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• 2016

Over recent years there has been considerable growth in interest in the use of biometric systems for personal authentication. Biometrics is a field of technology which has been and is being used in the identification of individuals based on some physical attribute. By using biometrics, authentication is directly linked to the person, rather than their token or password. Biometric authentication is a type of system that relies on the unique biological characteristics of individuals to verify identity for secure access to electronic systems. In 2013, Althobati et al. proposed an efficient remote user authentication protocol using biometric information. However, we uncovered Althobati et al.'s protocol does not guarantee its main security goal of mutual authentication. We showed this by mounting threat of data integrity and bypassing the gateway node attack on Althobati et al.'s protocol. In this paper, we propose an improved scheme to overcome these security weaknesses by storing secret data in device. In addition, our proposed scheme should provide not only security, but also efficiency since sensors in WSN(Wireless Sensor Networks) operate with resource constraints such as limited power, computation, and storage space.

• The Journal of Korean Academic Society of Nursing Education
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• v.9 no.2
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• pp.253-263
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• 2003

Rheumatoid arthritis patients not only suffer from the physical damage, but they are afflicted severely mental and psychologic after effects. Their depression and low self-esteem eventually yields serious mental damages, which makes difficult for them to recover. The states of mental health of arthritis patients are diversified depending on the characters and surrounding circumstances, although they may have suffered from the similar condition. Therefore this research was conbucted to the factors that can give positive influences to the patients. In recent time, social support for the arthritis patients has become an important factor that can positively influence their mental health. In other words, social support can act as an important environmental system for arthritis patients to recover their damaged mental health. In order to fulfill this purpose, 118 patients were examined to identify the relationship between the variables. The summary of the result obtained from the research is as follow: 1. The structural aspect of social support for arthritis patients showed the most of them had various social support network size and their highest support system were 'family', 'relative' and 'friends'. The functional aspect of social support for arthritis patients showed moderate degree and their highest sub component was 'approval'. 2. High correlation was found between duration of relationship, similarity, frequency of meeting and functional support. There was no relationship between depression, self-esteem and social support. 3. Therefore this research has suggested that nurses who care rheumatoid arthritis patient consider the above condition to develop self-help group.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.4
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• pp.15-24
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• 2008

In this paper, we propose a Cross-Layer Transmission Architecture (CLTA) to support power saving high-speed multimedia services in mobile ad-hoc wireless sensor networks(MAWSN). The main goals of this paper are in showing and proposing how the routing routes are decided on route stability based on mobility of mobile nodes to increase the operational lifetime of routes as well as how the transmit power can be saved in mobile ad-hoc wireless sensor networks. To obtain these goals, we propose a cross-layer architecture strategy which combines network layer technology with physical layer technology to get synergy effects in the view of transmission power saving. We consider a realistic approach, in the points of view of the MAWSN, based on mobile sensor nodes as well as fixed sensor nodes in sensor fields while the conventional research for sensor networks focus on mainly fixed sensor nodes. The performance evaluation of the proposed CLTA is performed via simulation and analysis.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.1
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• pp.71-77
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• 2018

The optical time domain reflectometer (OTDR) is the most widely used method to monitor problems with currently installed optical fibers. The OTDR is an instrument designed to test the FTTx network and evaluates the physical properties of the fiber, such as transmission loss and connection loss. It is important to improve the spatial resolution in order to accurately grasp the optical path problems by using the OTDR. When the pulse width is less than twice the distance between the two reflectors, the signals reflected from the two reflectors are reflected without overlap, so that the reflected signal can be distinguished. However, when the pulse width is larger than twice the distance between the two reflectors, so that the reflected signal can not be distinguished. In order to overcome these limitations, this paper proposed a method of improving spatial resolution by applying a super resolution algorithm. As a result of the simulation, the resolution is improved when the super resolution algorithm is applied, and the event interval can be analyzed more precisely.

• Journal of Communications and Networks
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• v.7 no.4
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• pp.401-407
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• 2005

Simulations are currently an essential tool to develop and test wireless sensor networks (WSNs) protocols and to analyze future WSNs applications performance. Researchers often simulate their proposals rather than deploying high-cost test-beds or develop complex mathematical analysis. However, simulation results rely on physical layer assumptions, which are not usually accurate enough to capture the real behavior of a WSN. Such an issue can lead to mistaken or questionable results. Besides, most of the envisioned applications for WSNs consider the nodes to be at the ground level. However, there is a lack of radio propagation characterization and validation by measurements with nodes at ground level for actual sensor hardware. In this paper, we propose to use a low-computational cost, two slope, log-normal path­loss near ground outdoor channel model at 868 MHz in WSN simulations. The model is validated by extensive real hardware measurements obtained in different scenarios. In addition, accurate model parameters are provided. This model is compared with the well-known one slope path-loss model. We demonstrate that the two slope log-normal model provides more accurate WSN simulations at almost the same computational cost as the single slope one. It is also shown that the radio propagation characterization heavily depends on the adjusted model parameters for a target deployment scenario: The model parameters have a considerable impact on the average number of neighbors and on the network connectivity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.342-351
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• 2008

In this paper, a new handover procedure for OFDM-based multi-hop relay systems is proposed to reduce the handover overhead by distinguishing inter-cell handover event from intra-cell handover event at the level of physical layer using a hierarchical design concept of preamble. A Subcell ID concept for identifying RS in a cell is proposed in the design of hierarchical manner, in addition to the existing Cell ID for identifying BS. The decision on either inter-cell handover or intra-cell handover is made by the signal quality measure of CBINR(Carrier of BS to Interference and Noise Ratio) and CRINR(Carrier of RS to Interference and Noise Ratio), provided by the hierarchical preamble. The proposed handover procedure can simplify scanning procedure and skip/simplify network re-entry procedure (capability negotiation, authorization, registration), resulting in a significant reduction of handover overhead.

• The Journal of Information Technology
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• v.3 no.2
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• pp.97-113
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• 2000

Recently, the electronic commerce(EC), driven by the development of Internet, has been one of the most important interests. Physical distribution in EC is one of the most important factors. Logistics will be one of the most important industries in the 21st century. Logistics, especially in related to EC presents enormous potential opportunities for logistics Companies. However, logistics companies in Korea still don't have international competitive and effective strategies for customer in compare with leading international logistics companies. So it is needed to study development strategies of logistics companies in Korea against leading international logistics companies. Logistics companies in Korea is able to learn from practical experience of logistics companies in developed country by benchmarking studies. It is three development strategies in order to develop Logistics Companies in Korea. $\circled1$ development of sophisticated logistics service product $\circled2$ reinforcement and enlargement of diverse added service $\circled3$ construction of international logistics network

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.8
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• pp.84-97
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• 2012

In wireless sensor networks, cluster structure brings on many advantages such as load balancing, energy saving, and distributed key management, and so on. To transform a physical network into the cluster structure, sensor nodes should invoke a cluster formation protocol. During the protocol operation, if some nodes are compromised and they do not conform to the protocol, an inconsistency of membership in a cluster happen. This splits the cluster and consequently increases the number of clusters and decreases the number of members in the cluster. In this paper, we propose a scheme which well copes with such a problem. First, our scheme generates two hop clusters where hop distance between any two nodes is at most two. Besides, our scheme employs verification of two hop distant nodes to prevent the cluster split induced by compromised nodes. Last, our scheme mainly employs broadcast transmissions to reduce energy consumption of nodes. Simulation results have proven that our scheme reduces the number of clusters and more secure and energy-efficient than other scheme.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.1 s.307
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• pp.67-74
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• 2006

Contort-aware computing technology is one of the key technology of ubiquitous computing in the mobile device environment. Context recognition computing enables computer applications that automatically respond to user's everyday activity to be realized. In this paper, We use accelerometer could sense activity states of the object and apply to mobile devices. This method for estimating human motion states utilizes various statistics of accelerometer data, such as mean, standard variation, and skewness, as features for classification, and is expected to be more effective than other existing methods that rely on only a few simple statistics. Classification algorithm uses simple decision tree instead of existing neural network by considering mobile devices with limited resources. A series of experiments for testing the effectiveness of the our context detection system for mobile applications and ubiquitous computing has been performed, and its result is presented.

• Smart Structures and Systems
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• v.25 no.5
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• pp.605-617
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• 2020

The existence of damages in structures causes changes in the physical properties by reducing the modal parameters. In this paper, we develop a two-stages approach based on normalized Modal Strain Energy Damage Indicator (nMSEDI) for quick applications to predict the location of damage. A two-dimensional IsoGeometric Analysis (2D-IGA), Machine Learning Algorithm (MLA) and optimization techniques are combined to create a new tool. In the first stage, we introduce a modified damage identification technique based on frequencies using nMSEDI to locate the potential of damaged elements. In the second stage, after eliminating the healthy elements, the damage index values from nMSEDI are considered as input in the damage quantification algorithm. The hybrid of Teaching-Learning-Based Optimization (TLBO) with Artificial Neural Network (ANN) and Particle Swarm Optimization (PSO) are used along with nMSEDI. The objective of TLBO is to estimate the parameters of PSO-ANN to find a good training based on actual damage and estimated damage. The IGA model is updated using experimental results based on stiffness and mass matrix using the difference between calculated and measured frequencies as objective function. The feasibility and efficiency of nMSEDI-PSO-ANN after finding the best parameters by TLBO are demonstrated through the comparison with nMSEDI-IGA for different scenarios. The result of the analyses indicates that the proposed approach can be used to determine correctly the severity of damage in beam structures.