• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.571-573
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• 2009

Mobile Ad-hoc Network(MANET) needs efficient node management because the wireless network has energy constraints. Mobility of MANET would require the topology change frequently compared with a static network. To improve the routing protocol in MANET, energy efficient routing protocol would be required as well as considering the mobility would be needed. Previously proposed a hybrid routing CACH prolong the network lifetime and decrease latency. However the algorithm has a problem when node density is increase. In this paper, we propose a new method that the CACHE(Context-aware Clustering Hierarchy and Energy efficient) algorithm. The proposed analysis could not only help in defining the optimum depth of hierarchy architecture CACH utilize, but also improve the problem about node density.

• Anxiety and mood
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• v.9 no.2
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• pp.147-153
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• 2013

Objective : Despite the chronic nature and high social costs, individuals with anxiety disorders seldom seek treatment. Thus, education for public awareness and screening for the illness is tremendously important for mental health professionals. This study summaries and presents the results from Anxiety Disorder Screening Program during the Mental Health Exposition held in Seoul in April, 2013. Methods : We analyzed the data from 116 participants who agreed and completed the screening questionnaires during their visits to two-day Anxiety Disorder Screening Program prepared by the Korean Academy of Anxiety Disorder. The questionnaire comprised of modified Mobility inventory for agoraphobia, Contents of worries, Penn State Worry Questionnaire, Life Events Checklist, and Abbreviated Posttraumatic Stress Disorder Checklist. Results : Participants demonstrated high rates of anxiety symptoms and possible anxiety disorders. Experience of panic attack was reported by 45%, lifetime and 16% in the past month by respondents. Phobia was reported by 46%. Participants had an average of 3.3 pathological worries and among those, social or interpersonal content was most common (46%). At least one lifetime traumatic event was reported by 64%. By the cut-off scores in the literature, 46% had possible generalized anxiety disorder and 58% possible posttraumatic stress disorder. Conclusion : Our results suggested that many visitors to Anxiety Disorder Screening Program were in fact treatment seeking after experiencing some forms of anxiety symptoms. Further efforts for delivery of medical information and increasing public awareness for anxiety disorders are needed.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.207-215
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• 2024

This study focuses on measuring the levels of naturally occurring radioactivity in the soil of Swabi, Khyber Pakhtunkhwa, Pakistan, as well as the associated health hazard. Thirty (30) soil samples were collected from various locations and analyzed for ²²⁶Ra, ²³²Th, and ⁴⁰K radioactivity levels using a High Purity Germanium detector (HPGe) gamma-ray spectrometer with a photo-peak efficiency of approximately 52.3%. The average values obtained for these radionuclides are 35.6 ± 5.7 Bqkg^-1, 47 ± 12.5 Bqkg^-1, and 877 ± 153 Bqkg^-1, respectively. The level of ²³²Th is slightly higher and ⁴⁰K is 2.2 times higher than the internationally recommended limit of 30 Bqkg^-1 and 400 Bqkg^-1, respectively. Various parameters were calculated based on the results obtained, including Radium Equivalent (Ra_eq), External Hazard (H_ex), Absorbed Dose Rate (D), Annual Gonadal Equivalent Dose (AGDE), Annual Effective Dose Rate, and Excess Lifetime Cancer Risk (ELCR), which are 170.3 ± 24 Bqkg^-1, 0.46 ± 0.06 Bqkg^-1, 81.4 ± 2.04 nGy h^-1, 582 ± 78.08 µSvy^-1, 99.8 ± 13.5 µSv Gy^-1, and 0.349 ± 0.04, respectively. These values are below the limits recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in 2002. This study highlights the potential radiation threats associated with natural radioactivity levels in the soil of Swabi and provides valuable information for public health and safety.

• Journal of dental hygiene science
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• v.11 no.3
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• pp.189-197
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• 2011

Objectives : The systematic health education to form the basic healthy lifestyle should be realized from elementary school, so oral health education at elementary school can determine the whole lifetime oral health. The elementary school health teacher's recognition and behavior who in charge of health promotion of students is important. Therefore, the study was conducted to enhance oral health education. Methods : Total 114 people among of 131 from health teacher Gwangju elementary school. Survey system is configured by referring to PRECEDE model. Results : In behavioral diagnosis the proportion of oral Health Education is less than 10%(58.8%), mostly educated in activity time (86.0%), the health teachers educate when it is needed(53.5%). In predisposing diagnosis in the eight areas of health education, the oral health education is ranked as fourth, fifth. Even in the next year project, the oral health education ratio was 21.9 percent. In enabling diagnosing every year the Oral health education training experienced rate is 13.2%, satisfaction rate is 33.3%. In reinforcing diagnosing disability element in the regular education course are the lack of oral health-related information (46.7%), lack of materials needed for education (30.6%), lack of training opportunities (21.4%). Conclusion : In further research, oral health education textbooks, materials and methods should be developed. At the foundation of there developments, the elementary oral health education program should be more fully developed and conducted and also the evaluation of its effectiveness will need.

• English Language & Literature Teaching
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• no.6
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• pp.219-239
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• 2000

There has been a growing enthusiasm in Korea for the early education of English as a foreign language (EFL). The present study examined the validity of the Critical Period Hypothesis in terms of the Universal Grammar (UG), in three different types of learning contexts - first language (L1), second language (SL), and foreign language (FL) learning contexts. While previous research findings in L1 and SL learning contexts suggest that UG principles and parameters are accessible to language learners only for the early years of lifetime, this article argues that their results - and even the methods - cannot be applied to EFL settings and that independent studies on the EFL context are, required. It also proposes the recent UG notion of functional categories as the most appropriate subject in the discussion of Korean EFL learners' access to UG. Findings on foreign language contexts, including the author's own, strongly indicate that UG is not sensitive to learners' starting ages in FL settings. If young children in FL contexts cannot develop their interlanguage grammar based on UG, the existing teaching methods for young children should be revised.

• Journal of the Korean Home Economics Association
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• v.29 no.2
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• pp.241-248
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• 1991

The aim of this study is to propose the criteria for a evaluation model of the lifetime household work and organize the model. The results were as follows: Three criteria for a evaluation model of the life-time household work were proposed. $\circled1$ An appropriate framework of the evaluation model should be based on the transition of the family life. $\circled2$ The model should include major variables influencing the value of household work of homemaker. $\circled3$ The model should be flexible enough to accommodate various evaluation methods, and should reflect idiosyncracies of different evaluation methods. In view of the criteria stated above, the present study is based on the family life cycle framework. And the age of the last offspring exhibits a consistent major influence in the evaluation based on the household work hours, while the education level of homemakers shows a consistent major influence in the evaluation based on household worker. So as to reflect these two major variables in the family life cycle framework.

• Journal of Communications and Networks
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• v.14 no.3
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• pp.310-318
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• 2012

Detecting intrusion attacks accurately and rapidly in wireless networks is one of the most challenging security problems. Intrusion attacks of various types can be detected by the change in traffic flow that they induce. Wireless industrial networks based on the wireless networks for industrial automation-process automation (WIA-PA) standard use a superframe to schedule network communications. We propose an intrusion detection system for WIA-PA networks. After modeling and analyzing traffic flow data by time-sequence techniques, we propose a data traffic prediction model based on autoregressive moving average (ARMA) using the time series data. The model can quickly and precisely predict network traffic. We initialized the model with data traffic measurements taken by a 16-channel analyzer. Test results show that our scheme can effectively detect intrusion attacks, improve the overall network performance, and prolong the network lifetime.

• International Journal of Reliability and Applications
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• v.15 no.1
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• pp.1-9
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• 2014

Let X and $X_t$ denote the lifetime and the residual life at age t, respectively. X is said to be a NBUL (new better than used in Laplace transform order) random variable if $X_t$ is smaller than X in Laplace order, i.e., $X_t{\leq}_{LT}X$. We propose a new test statistics for testing exponentiality versus NBUL class of life distribution. The tests by Hollender and Proschan (1975) and the generalized Hollender and Proschan test by Ains and Mitra (2011) are considered as special cases of the our of test statistics. Our proposed test statistics is simple, consistent and asymptotically normal. Efficiency and powers of the test statistics for some commonly used distributions in reliability are discussed. Finally, real examples are presented to illustrate the theoretical results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.5
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• pp.55-62
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• 2017

The grate bar, a component used in steel mills, is used in harsh environments where external disturbances such as high temperature, abrasion, corrosion, and impacts are present. Therefore, in this study, spray-coating was performed on the most severely affected surface to extend the lifetime of the grate bar. The thermal and mechanical properties of the sprayed coated bars were investigated based on the performances under abrasion, thermal shock, tension, and sand blasting, and the microstructures by microscope. By analyzing the thermal and mechanical properties of the uncoated original grate bar and coated grate bar and comparing them with one another, the physical performance improvement of the coated grate bar can be verified.

• ETRI Journal
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• v.44 no.2
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• pp.274-285
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• 2022

Retransmission in optical burst switching networks is a solution to recover data loss by retransmitting the dropped burst. The ingress node temporarily stores a copy of the complete burst and sends it each time it receives a retransmission request from the core node. Some retransmission schemes have been suggested, but uncontrolled retransmission often increases the network load, consumes more bandwidth, and consequently, increases the probability of contention. Controlled retransmission is therefore essential. This paper proposes a new controlled retransmission scheme for loss recovery, where the available bandwidth of wavelength channels and the burst lifetime are referred to as network conditions to determine whether to transmit a dropped burst. A retrial queue-based analysis model is also constructed to validate the proposed retransmission scheme. The simulation and analysis results show that the controlled retransmission scheme is more efficient than the previously suggested schemes regarding byte loss probability, successful retransmission rate, and network throughput.