• Composites Research
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• v.18 no.3
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• pp.14-20
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• 2005

This paper presents a study on the permittivities of the carbon black/epoxy composite at microwave frequency. The measurements were performed at the frequency band of $1\;GHz\~18\;GHz$. The experimental data show that the complex permittivities of composites depend strongly on the natures and concentrations of the carbon black dispersion. The frequency characteristics of dielectric constants and ac conductivities of composites show the good conformity with descriptions of the percolation theory, satisfying the general scaling relation. The measuring frequency band is over the critical frequency, below that the ac conductivities of composites are constant to the frequency. The values of dielectric constants and ac conductivities have consistent relationships with the carbon black concentration. The A new scheme, that is a branch of Lichtenecker-Rother formula, is proposed to obtain a mixing law to describe the complex permittivities of the composites as function frequency and concentration of carbon black.

• Journal of the Korean Magnetics Society
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• v.27 no.2
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• pp.49-53
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• 2017

Metamaterials composed of split cut wire (SCW) on grounded polyimide film substrate have been investigated for the aim of electromagnetic wave absorbers operated in THz frequency band. Reflection loss and current density distributions are numerically simulated with variations of the SCW geometries using the commercial software. The minimum reflection loss lower than -20 dB has been identified at 5.5~6.5 THz. The simulated resonance frequency and reflection loss can be explained on the basis of the circuit theory of an inductance-capacitance (L-C) resonator. Dual-band absorption can be obtained by arrangement of two SCWs of different length on the top layer of the grounded substrate, which is due to multiple magnetic resonances by scaling of SCWs. With increasing the side spacing between SCWs, a more enhanced absorption peak is observed at the first resonance frequency that is shifted to a lower frequency.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.6
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• pp.1241-1246
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• 2009

It has been suggested that Tae-Eum peoples are prone to obesity. Although extensive clinical observations have shown this tendency in Sasang Constitutional Medicine (SCM), no scientific hypothesis has been proposed to delineate its mechanism. According to SCM theory, Tae-Eum peoples have a hypoactive lung system and a hyperactive liver system. In this paper we propose a new hypothesis explaining the tendency of obesity in Tae-Eum people in the viewpoint of cell physiology. The hypoactive lung system might imply an attenuated 'respiration' at the cell/subcell level, namely mitochondrial oxygen consumption. Because a functional weakness in mitochondria energy metabolism indicates intrinsic hypo-activity in the consumption (or production) of metabolic energy, we deduced that the tendency can easily induce body weight gain via an increase in anabolism. This relation is also introduced in the graph of cellular metabolic power against body weight. To test this hypothesis, we analyzed the clinical data with 863 subjects. Statistical analysis of the data showed that Tae-Eum peoples had relatively a lower cellular metabolic power, and that the percentage of peoples with BMI>25 was significantly higher than that of the other constitutional types.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.5
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• pp.830-836
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• 2006

In this paper described an auto tuning neuro-fuzzy PID controller based neural network. The PID type controller has been widely used in industrial application due to its simply control structure, easy of design, and inexpensive cost. However, control performance of the PID type controller suffers greatly from high uncertainty and nonlinearity of the system, large disturbances and so on. In this paper will design to take advantage of neural network fuzzy theory and pid controller auto toning technique. The value of initial scaling factors of the proposed controller were determined on the basis of the conventional PID controller parameters tuning methods and then they were adjusted by using neural network control techniques. This controller simple structure and computational complexity are less, and also application is easy and performance is excellent in system that is strong and has nonlinearity to system dynamic behaviour change or disturbance. Finally, the proposed auto tuning neuro-fuzzy controller is applied to magnetic levitation. Simulation results demonstrated that the control performance of the proposed controller is better than that of the conventional controller.

• Journal of Korean society of Dental Hygiene
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• v.21 no.6
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• pp.793-803
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• 2021

Objectives: The purpose of this study was to investigate the current status of dental hygiene curricula related to clinical practice in Korea. Methods: Clinical work included the categories 'history taking, infection control, oral prophylaxis, preventive treatment, education/counseling, radiography/reading, assisting/cooperation, impression/bite registration, anesthesia, etc.', and 66 works were finally selected based on the frequent tasks of dental hygienists. The subjects were made to answer nine questionnaires. Results: It was found that the theory and practice of the main works operated quite differently in lectures and practice in each school. All types of practice were applied to all schools in the case of 'scaling'. The evaluation of clinical practice was also found to be very different from school to school. Conclusions: For dental hygienists to establish expertise in clinical practice and promote quality improvement, it is necessary to develop a core curriculum focusing on clinical practice. The standardized curriculum should be improved to an efficient and competency-centered one defining clearly the role of dental hygienists considering the needs and importance of clinical practice.

• Korean Journal of Culture and Social Issue
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• v.19 no.3
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• pp.457-485
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• 2013

This study attempted to discover the dimensions of Korean culture, with the presumption that the cross-cultural studies(Hofstede, 1980, 1997; Schwartz, 1992, 1994; Trompenaars and Hampden-Turner, 1997; House et al., 2004) have limitation to explain non-western culture including Korean culture. Even though there are some Korean cultural studies, they used heuristic approaches applying the authors' experiences and intuitions. This study applied the Cultural Consensus Theory to overcome the previous studies' shortcomings and to discover the dimensions that can be empirically proved by data. In specific this study conducted in-depth interview, used content analysis, did frequency analysis, and applied pilesort technique, multidimensional scaling and network analysis. As a result, this study obtained five categories: public self-consciousness, group-focused orientation, affective human relations, hierarchical culture, and result-orientation. It is expected that these dimensions can be used as important variables that may explain Korean social phenomena.

• Korean Journal of Environmental Biology
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• v.28 no.4
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• pp.179-187
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• 2010

The Theory of Island Biogeography describes that the number of species on an island affected by island area and distance from the mainland. This study was performed to compare and analyze the community structure of the macro-invertebrates in three isolated islands, around Korean waters in terms of the Theory of Island Biogeography. Macrobenthic animals were collected using a modified underwater quadrat in August 2009. A total of 104 macrobenthic species were sampled with a mean density of 399 individuals $m^{-2}$ and biomass of 1,506.70 g $m^{-2}$. Based on the abundance and biomass data, there were 10 dominant species accounting for approximately 67.17% of total individuals. The highest densities were found in the amphipoda Amphipoda spp., the bivalvia Modiolus agripetus and Mytilus coruscus, the Sipunculida Phascolosoma scolops and the polychaeta Syllidae unid.. On the contrary, the top ten species made up 95.66% of the total biomass while the three most abundant, the bivalves M. coruscus, Streostria circumpicta and M. agripetus. The conventional multi-variate statistics (cluster analysis and non-metric multi-dimensional scaling) applied to assess spatial variation in macrobenthic assemblages. Cluster analysis and nMDS ordination analysis based on the Bray-Curtis similarity identified 2 station groups. The group 1 was consisted with Gageodo (except for lower station at Transect 2) and Dokdo station and was numerically dominated by the polychaetes Eunice antennata and Syllidae unid., the cirripedia Megabalanus rosa and the bivalvia M. coruscus. However, group 2 was associated with Sohwado station and was characterized by high abundance of the anomura Petrolisthes japonicus, the gastropoda Lirularia pygmaea and the brachiopoda Coptothyris grayi. In conclusion, these results suggested that the species diversity and community structure of macrobenthos in three isolated island seemed slightly related to island area and distance from the mainland.

• Journal of KIISE:Information Networking
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• v.37 no.3
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• pp.167-174
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• 2010

Recently the distributed topology control algorithm for constructing the Recrystallization Topology in the unstructured peer-to-peer network was proposed. In this paper, we prove that such a hierarchical topology is a scale-free power-law network. We present a model of a construction process of the distributed protocol, and analyze it based on a mean-field approximation and the continuum theory, so that we show that the constructed Recrystallization Topology is a scale-free network. In the proposed model, all nodes are born with some initial attractiveness and the system incorporates the rewiring of some links at every time step. Some old links are removed with the anti-preferential probability, and some new links are added with preferential probability. In other words, according to the distributed algorithm, each node makes connections to the more-preferential nodes having higher hit-ratio than other nodes, while it disconnects the anti-preferential nodes having lesser hit-ratio. This gives a realistic description of the local processes forming the recrystallization topology in unstructured peer-to-peer network. We calculate analytically the degree distribution. The analytic result indicates that the constructed network is a scale-free network, of which the scaling exponent is 3.

• Journal of Korean society of Dental Hygiene
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• v.9 no.4
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• pp.768-783
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• 2009

Objectives : The purpose of this study was to analyze dental records performed through a dental hygiene process and provide basic data on clinical training education for dental hygienists. Methods : The dental hygiene records of 440 senior dental hygiene students in Y University from March 2005 to September 2008, were examined. The needs of the clients confirmed by the dental hygiene diagnosis was based on Human Need Theory. The client's needs and the number of visits were analyzed according to the general characteristics(gender, age). The contents of the dental hygiene implementation performed according to the needs were divided into dental hygiene care and oral health education. The dental hygiene evaluation was classified into 'Met of Goal', 'Partially Met of Goal', and 'Unmet of Goal' according to the dental hygiene diagnosis. Data analysis was performed for the Frequency statistics and a Fisher's exact test using SPSS 12.0K for Windows. Results : 1. The clients were mostly aged in their 20's(307 clients). 2. The dental hygiene care usually performed was 'Scaling' and 'Recommendation to visit a dental clinic', and the education performed was 'How to brush teeth'. The implementation result from the need to Freedom of Stress was as simple as 'Be careful when treating' and 'Explanation of medical treatment and tools'. 3. The dental hygiene evaluation showed a higher met rate in the field of education than in that of the dental hygiene care. The reason for unmet the goal was 'Lack of the client's efforts and they didn't visit dental clinic'. Conclusions : The search for a range of clients for dental hygiene process should be made through effective connections between the local community institutions and schools. It was suggested that they should be strength the practical exercises for clients suffering dental anxiety and stress in dental treatments. In addition, education and attempts to motivate the clients should be performed according to their characteristics.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.2
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• pp.177-187
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• 2000

In the past several years, many systems which adopted ring topology with high-speed unidirectional point-to-point links have emerged to overcome the limit of bus for interconnection network of clustered multiprocessor system. However, rapid increase of processor speed and performance improvement of local bus and memory system limit scalability of system with point-to-point link of standard bandwidth. Therefore, necessity to extend bandwidth is emphasized. In this paper, we adopt PANDA system as base model, which is clustering-based multiprocessor system. By simulating a model adopting commercial processor and local bus specification, we show that point-to-point link is bottleneck of system performance, and bandwidth expansion by more than 200% is needed. To expand bandwidth of interconnection network, it needs excessive design cost and time to develop new point-to-point link with doubled bandwidth. As an alternative to double bandwidth, we propose several ways to implement dual ring -simple dual ring, transaction-separated dual ring, direction-separated dual ring- by using off-the-shelf point-to-point links with IEEE standard bandwidth. We analyze pros. and cons. of each model compared with doubled-bandwidth single ring by simulation.