• Tuberculosis and Respiratory Diseases
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• v.49 no.5
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• pp.558-567
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• 2000

Background : Recently, serologic techniques for tuberculosis have been developed and some of them, which are focusing on detection of serum antibodies mainly directed against specific 38-kDa Mycobacterium tuberculosis, have already been introduced into the markel. In this study, diagnostic significance of a new serologic test(ELISA kit) for pulmonary tuberculosis was evaluated. Method : Serologic test with newly developed ELISA kit was performed upon 474 individuals, who include 333 active pulmonary tuberculosis patients, 80 healthy cases, and 61 tuberculosis contact cases. This serologic test was based on the ELISA technique and designed to detect antibodies to mixed complex antigens including 38-kDa, which were developed by Erume Biotech Co., Seoul. Active pulmonary tuberculosis was diagnosed by sputum AFB smear and culture methods. Results : The seropositivities using this ELISA kit were 82.1% and 73.6% in smear-positive and negative groups among active pulmonary tuberculosis, respectively. And, it also showed that seronegativities were 97.5% and 85.2% in healthy and contact groups, respectively. As a whole, the results of our study using the ELISA kit as a diagnostic method for pulmonary tuberculosis showed 80.0% sensitivity for active pulmonary tuberculosis, 97.5% specificity, 96.1% positive predictive value, and 65.0% negative predictive value when the prevalence of tuberuclosis in the samples was 60.1%. Conclusion : Our results reveal that the detection of antibody its reaction with 38-kDa antigen of M. tuberculosis is not sufficient to be accepted as single diagnostic method for pulmonary tuberculosis. However, they suggest that ELISA kit may be considered as an adjunctive test to standard diagnostic techniques of pulmonary tuberculosis.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.439-443
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• 2002

The purpose of this study was to analyze the parental consultation. Also, it was to investigate the tendency divided into different subjects. The subjects were 2142 questions on korean academy of pediatric dentistry homepage. The questions were categorized into 7 subjects, 37 subdivided subjects and children age. The results were as follows: 1. Age group was divided into $0{\sim}6months$, $7{\sim}12months$, $13{\sim}24months$, $25{\sim}36months$, $3{\sim}6years$, $7{\sim}12years$ 12years and over 13 years. $13{\sim}24months$ and $3{\sim}6years$ age group had the largest number of questions. 2. The subject were growth & development, development disturbance & oral disease, behavior management, operative & endodontic treatment, dentition & occlusal guidance, traumatic injury & surgery and etc. Development disturbance & oral disease had the largest number of questions. 3. In subdivided subjects, operative & endodontic treatment showed the most, followed by development & eruption of teeth, traumatic injury, cross-bite, tooth brushing methods in sequence. 4. In age group within subdivided subjects, the most frequent question was neonatal & natal tooth in $0{\sim}6months$, development & eruption of teeth in $7{\sim}12months$, $13{\sim}24months$, operative & endodontic treatment in $25{\sim}36months$, $3{\sim}6years$, time & method of orthodontics in $7{\sim}12years$ and operative & endodontic treatment in over 13years. 5. The questions about cross-bite, traumatic injury and soft tissue disease were distributed evenly in age group.

• Journal of Korean Home Economics Education Association
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• v.31 no.4
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• pp.1-18
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• 2019

The purpose of this study was to analyze the research trend in home economics education using network text analysis method. The 586 research articles published in the Journal of Home Economics Education Association between July, 2003 and December 2018 were examined using Neckinger 4, a social network analysis software. The frequency and centrality measures(degree centrality, closeness centrality, and betweenness centrality) were calculated for the words appeared throughout the whole period, and the centrality analysis and LAD(Latent Dirichlet Allocation) were conducted for the four sub-periods. The results are as follows: first, the most frequently appeared words are parents, culture, unit, health, career, consumption, practicality, etc. The words such as parents and management scored high in degree centrality; parents and male students in closeness centrality; and male students and units in betweenness centrality. Second, when divided into four periods, the words such as education, family, purpose, class, middle school, and school appeared most frequently across the periods; but some words such as 'purpose' (in period 3 and 4), or 'process' (in period 4) were salient only in certain periods. Third, the words with high centrality were consistent regardless of the types of centrality within each period. Fourth, the topic analysis using LAD showed that curriculum, textbook, family healthiness, teaching-learning, evaluation, dietary life, appearance management, and consumption were the topics consistently appeared across all periods. The topics have become diversified and deepened. New topics such as teacher training and safety appeared in later periods, possibly due to the curriculum and national policy changes, and housing as a less represented topic is suggested as an area that needs further research attention. This study has implication in that it allows researchers to identify the major research interests and the trends in research by researchers in home economic education.

• Journal of Intelligence and Information Systems
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• v.16 no.4
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• pp.159-172
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• 2010

The recommender system is one of the possible solutions to assist customers in finding the items they would like to purchase. To date, a variety of recommendation techniques have been developed. One of the most successful recommendation techniques is Collaborative Filtering (CF) that has been used in a number of different applications such as recommending Web pages, movies, music, articles and products. CF identifies customers whose tastes are similar to those of a given customer, and recommends items those customers have liked in the past. Numerous CF algorithms have been developed to increase the performance of recommender systems. Broadly, there are memory-based CF algorithms, model-based CF algorithms, and hybrid CF algorithms which combine CF with content-based techniques or other recommender systems. While many researchers have focused their efforts in improving CF performance, the theoretical justification of CF algorithms is lacking. That is, we do not know many things about how CF is done. Furthermore, the relative performances of CF algorithms are known to be domain and data dependent. It is very time-consuming and expensive to implement and launce a CF recommender system, and also the system unsuited for the given domain provides customers with poor quality recommendations that make them easily annoyed. Therefore, predicting the performances of CF algorithms in advance is practically important and needed. In this study, we propose an efficient approach to predict the performance of CF. Social Network Analysis (SNA) and Artificial Neural Network (ANN) are applied to develop our prediction model. CF can be modeled as a social network in which customers are nodes and purchase relationships between customers are links. SNA facilitates an exploration of the topological properties of the network structure that are implicit in data for CF recommendations. An ANN model is developed through an analysis of network topology, such as network density, inclusiveness, clustering coefficient, network centralization, and Krackhardt's efficiency. While network density, expressed as a proportion of the maximum possible number of links, captures the density of the whole network, the clustering coefficient captures the degree to which the overall network contains localized pockets of dense connectivity. Inclusiveness refers to the number of nodes which are included within the various connected parts of the social network. Centralization reflects the extent to which connections are concentrated in a small number of nodes rather than distributed equally among all nodes. Krackhardt's efficiency characterizes how dense the social network is beyond that barely needed to keep the social group even indirectly connected to one another. We use these social network measures as input variables of the ANN model. As an output variable, we use the recommendation accuracy measured by F1-measure. In order to evaluate the effectiveness of the ANN model, sales transaction data from H department store, one of the well-known department stores in Korea, was used. Total 396 experimental samples were gathered, and we used 40%, 40%, and 20% of them, for training, test, and validation, respectively. The 5-fold cross validation was also conducted to enhance the reliability of our experiments. The input variable measuring process consists of following three steps; analysis of customer similarities, construction of a social network, and analysis of social network patterns. We used Net Miner 3 and UCINET 6.0 for SNA, and Clementine 11.1 for ANN modeling. The experiments reported that the ANN model has 92.61% estimated accuracy and 0.0049 RMSE. Thus, we can know that our prediction model helps decide whether CF is useful for a given application with certain data characteristics.

• Journal of Intelligence and Information Systems
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• v.22 no.4
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• pp.157-176
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• 2016

For a long time, mobile phone had a sole function of communication. Recently however, abrupt innovations in technology allowed extension of the sphere in mobile phone activities. Development of technology enabled realization of almost computer-like environment even on a very small device. Such advancement yielded several forms of new high-tech devices such as smartphone and tablet PC, which quickly proliferated. Simultaneously with the diffusion of the mobile devices, mobile applications for those devices also prospered and soon became deeply penetrated in consumers' daily lives. Numerous mobile applications have been released in app stores yielding trillions of cumulative downloads. However, a big majority of the applications are disregarded from consumers. Even after the applications are purchased, they do not survive long in consumers' mobile devices and are soon abandoned. Nevertheless, it is imperative for both app developers and app-store operators to understand consumer behaviors and to develop marketing strategies aiming to make sustainable business by first increasing sales of mobile applications and by also designing surviving strategy for applications. Therefore, this research analyzes consumers' mobile application usage behavior in a frame of substitution/supplementary of application categories and several explanatory variables. Considering that consumers of mobile devices use multiple apps simultaneously, this research adopts multivariate probit models to explain mobile application usage behavior and to derive correlation between categories of applications for observing substitution/supplementary of application use. The research adopts several explanatory variables including sociodemographic data, user experiences of purchased applications that reflect future purchasing behavior of paid applications as well as consumer attitudes toward marketing efforts, variables representing consumer attitudes toward rating of the app and those representing consumer attitudes toward app-store promotion efforts (i.e., top developer badge and editor's choice badge). Results of this study can be explained in hedonic and utilitarian framework. Consumers who use hedonic applications, such as those of game and entertainment-related, are of young age with low education level. However, consumers who are old and have received higher education level prefer utilitarian application category such as life, information etc. There are disputable arguments over whether the users of SNS are hedonic or utilitarian. In our results, consumers who are younger and those with higher education level prefer using SNS category applications, which is in a middle of utilitarian and hedonic results. Also, applications that are directly related to tangible assets, such as banking, stock and mobile shopping, are only negatively related to experience of purchasing of paid app, meaning that consumers who put weights on tangible assets do not prefer buying paid application. Regarding categories, most correlations among categories are significantly positive. This is because someone who spend more time on mobile devices tends to use more applications. Game and entertainment category shows significant and positive correlation; however, there exists significantly negative correlation between game and information, as well as game and e-commerce categories of applications. Meanwhile, categories of game and SNS as well as game and finance have shown no significant correlations. This result clearly shows that mobile application usage behavior is quite clearly distinguishable - that the purpose of using mobile devices are polarized into utilitarian and hedonic purpose. This research proves several arguments that can only be explained by second-hand real data, not by survey data, and offers behavioral explanations of mobile application usage in consumers' perspectives. This research also shows substitution/supplementary patterns of consumer application usage, which then explain consumers' mobile application usage behaviors. However, this research has limitations in some points. Classification of categories itself is disputable, for classification is diverged among several studies. Therefore, there is a possibility of change in results depending on the classification. Lastly, although the data are collected in an individual application level, we reduce its observation into an individual level. Further research will be done to resolve these limitations.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.3
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• pp.23-32
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• 2010

The purpose of this study is to quantify human energy budgets for different structures of outdoor spatial surfaces affecting thermal comfort, to analyze the impacts of tree shading on building energy savings, and to suggest desirable strategies of urban greenspace planning concerned. Concrete paving and grass spaces without tree shading and compacted-sand spaces with tree shading were selected to reflect archetypal compositional types for outdoor spatial materials. The study then estimated human energy budgets in static activity for the 3 space types. Major determinants of energy budgets were the presence of shading and also the albedo and temperature of base surfaces. The energy budgets for concrete paving and grass spaces without tree shading were $284\;W/m^2$ and $226\;W/m^2$, respectively, and these space types were considerably poor in thermal comfort. Therefore, it is desirable to construct outdoor resting spaces with evapotranspirational shade trees and natural materials for the base plane. Building energy savings from tree shading for the case of Daegu in the southern region were quantified using computer modeling programs and compared with a previous study for Chuncheon in the middle region. Shade trees planted to the west of a building were most effective for annual savings of heating and cooling energy. Plantings of shade trees in the south should be avoided, because they increased heating energy use with cooling energy savings low in both climate regions. A large shade tree in the west and east saved cooling energy by 1~2% across building types and regions. Based on previous studies and these results, some strategies including indicators for urban greenspace planning were suggested to improve thermal comfort of outdoor spaces and to save energy use in indoor spaces. These included thermal comfort in construction materials for outdoor spaces, building energy savings through shading, evapotranspiration and windspeed mitigation by greenspaces, and greenspace areas and volume for air-temperature reductions. In addition, this study explored the application of the strategies to greenspace-related regulations to ensure their effectiveness.

• Korean Journal of Construction Engineering and Management
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• v.17 no.5
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• pp.120-129
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• 2016

The user cost is an important analysis item which should be considered together with life-cycle of facility, administrator cost and discount rate in LCCA for efficient asset management of SOC facilities. Especially, a significant delay cost occurs often for users in the road field due to a work zone for cleaning and maintenance, and in such case, the administrator should consider the administrator cost as well as the user cost for more rational decision making. However, the user cost has not been considered in most decision making steps until recently and relevant studies also have not been carried out actively. In this study, the methodology to estimate the user cost and delay cost required in the decision making step using the traffic flow model and the direct benefit estimation model in the traffic facility investment evaluation guideline is suggested. And, the traffic flow model was estimated on 4 national highway sections where maintenance was actually carried out in 2014 using VISSIM and, the user cost and the delay cost were estimated based on the suggested methodology. The analysis result showed that the average user cost of $17,569,000KRW/km{\times}day$ occurred on Section A with approximately 30,000 AADT before a work zone occurred, and in case the first lane was blocked for maintenance, the delay cost of $10,193,000KRW/km{\times}day$ (158%) on average occurred additionally. The delay cost of $1,507,000KRW/km{\times}day$ (115%) and $1,985,000KRW/km{\times}day$ (119%) occurred on Sections B and D with approximately 20,000 AADT respectively and the delay cost of $262,000KRW/km{\times}day$ (105%) occurred on Section C with approximately 10,000 AADT. This result of this study was estimated based on the simulation of traffic flow model so that there is a limitation in its actual application. A study ot develop a highly appropriate model using actual observation data and improve the possibility to apply it through the verification using the simulation will be necessary in future.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.57-66
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• 2007

Natural gases generally consist of mainly $^{12}C$ and about 1.1% of $^{13}C$. It is well known that a stable carbon isotope, $^{13}C$, has been widely used for the applications of medical, pharmaceutical, and agricultural tracers. As a result, the development of the separation and concentrating technology of $^{13}C$ can cause of high value-added products and the possibility of the generation of new carbon materials, In general, there are two kinds of approaches to obtain a stable $^{13}C$ isotope by the separation of cryogenic distillation. One is to obtain a concentrated $^{13}CH_4$ isotope from natural gas. Another approach is to get concentrated $^{13}CO$ by distillation followed by a chemical reaction of $CH_4$ and $H_2O$. In this study, rigorous process simulations of the cryogenic distillation have been performed and analyzed for the concentrated separation of $^{13}C$ isotopes from LNG and NG by using commercial process simulator. Due to the very small differences of relative volatilities and separabilities of $^{12}C$ and $^{13}C$, the process design and operation of effective separation and concentration of $^{13}C$ need special strategies and feasibility studies. Utilization of vapor pressure data to acentric factor in SRK equation of state and optimized process conditions have been able to predict for the effective of the separation yield and concentration of $^{13}C$ for the cryogenic distillation. The various operation strategies for both batch and continuous cryogenic distillation are also studied and suggested for the basic design of the process. Development of this study can provide a tool for the effective design and operation of the cryogenic separation of $^{13}C$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.12
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• pp.605-619
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• 2014

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.1
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• pp.33-39
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• 2010

Objective: Birth sex ratio (BSR) with human IVF-ET program is an interesting subject of social and scientific issue but very little information is available in Korea. This study was performed to assess the BSR with IVF-ET and to suggest the effective factors on the BSR. Methods: The national data from 1991~2008 were obtained from governmental Statistics Korea and the delivery data of human IVF-ET program on 2007 and 2008 were provided from the Ministry for Health, Welfare and Family Affairs. The BSR were statistically analyzed according to methods of IVF and to transferred embryos from fresh or frozen-thawed cycles. Results: The BSRs of Korean populations were over 1.10 up to 2002, and then it declined and maintained to 1.06 as balance BSR on 2007 and 2008. In human IVF-ET program, the BSRs were 1.07 on 2007 and 1.06 on 2008, respectively. Conventional IVF on 2008 showed the highest BSR as 1.10, and ICSI the lowest on 2008 as 1.01. There was no significant difference of BSRs related to the methods of in vitro fertilization and the feature of transferred embryos. Conclusion: The BSR of Korea showed 1.06~1.07 as normal and balanced state on 2007 and 2008 both general populations and human IVF-ET program. To the best of our knowledge, this is the first study to evaluate the BSR of human IVF-ET in Korea. There is a need to expand the further studies for national statistics and influencing factors on the BSR with IVF-ET.