• 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.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.169-174
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• 2008

Statement of problem: Changes of the marginal bone around dental implants have significance not only for the functional maintenance but also for the esthetic success of the implant. It was proposed that bone-retention elements such as microthreads at the coronal part of implant might help maintain the marginal bone level. Purpose: This study was designed to evaluate the effect of microthread configuration within the marginal coronal portion of the implant fixture at the marginal bone changes after loading around two different external hex implants. Material and methods: Twenty-four patients were included and randomly assigned to treatment with $Br{{\aa}}nemark$ system implants (Group 1, rough-surfaced implants, n=20) and Oneplant system implants (Group 2, rough-surfaced neck with microthreads, n=20). Clinical and radiographic examinations were conducted at baseline (implant loading) and 1 year postloading. Data analysis was performed by the SAS statistical package version 9.1.3 (SAS Institute, Cary, NC, USA) and the final model was calculated by the MIXED procedure (three-level ANCOVA) for marginal bone change of each test group at baseline and 1 year follow-up. Results: Comparing to baseline, significant differences were noted in marginal bone level changes for the 2 groups at 1 year follow-up (P<0.05). Group 1 had a mean crestal bone level changes of $0.83{\pm}0.31mm$; Group 2 had a mean crestal bone level changes of $0.44{\pm}0.36mm$. Rough-surfaced with microthreads implants showed significantly less marginal bone loss than rough surfaced neck without microthread implants. Conclusion: A rough surface with microthreads at the implant was beneficial design to maintain the marginal bone level against functional loading.

• Journal of the Korean association of regional geographers
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• v.7 no.3
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• pp.107-120
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• 2001

This study is concerned with providing a reliable procedure of calibrating a set of places specific distance parameters and with applying it to U.S. inter-State migration flows between 1985 and 1900. It attempts to conform to recent advances in quantitative geography that are characterized by an integration of ESDA(exploratory spatial data analysis) and local statistics. ESDA aims to detect the spatial clustering and heterogeneity by visualizing and exploring spatial patterns. A local statistic is defined as a statistically processed value given to each location as opposed to a global statistic that only captures an average trend across a whole study region. Whereas a global distance parameter estimates an averaged level of the friction of distance, place-specific distance parameters calibrate spatially varying effects of distance. It is presented that a poisson regression with an adequately specified design matrix yields a set of either origin-or destination-specific distance parameters. A case study demonstrates that the proposed model is a reliable device of measuring a spatial dimension of migration, and that place-specific distance parameters are spatially heterogeneous as well as spatially clustered.

• Journal of Veterinary Clinics
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• v.10 no.1
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• pp.65-94
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• 1993

This study examined metabolic profiles of 1349 Holstein cows from 91 commercial herds. Thirteen parameters which are consisted of twelve blood components and body condition score were examined and their mean values. standard deviations and standard limits, which are 80% confidential limits, in each lactational stage were reported. The variations of each parameter affected by season, individual milk yield, adjusted corrected milk yield of herd. and lactation number were also reported. A model of metabolic profile test applicable to this country where the average number of cows in a herd is small as to be fifteen is designed. Metabolic profiles as reflected in each parameter were discussed in relation to adequacy of dietary intake for production, milk production, reproductive performance, and diseases, and the possible measure to improve productivity of dairy cows were proposed. Much of the variation in parameters was due to differences between herds, and less to differences between seasons, differences between individual milk yield, and differences between lactational stages. As the average herd size in this country is small, it is believed that all the cows in a herd must be sampled, and the individual result of each parameter was compared with the standard limit for each lactational stage, and the percentage of cows which are outside the standard limits in a herd was calculated to use as a criteria for evaluation of the herd. Data outside the 99% confidential limits were to be deleted at first, but when the trends of the data outside the 99% confidential limits are same as the trends of the data within 99% confidential limits, the deleted data must be reviewed again, otherwise some important informations would be missed. The mean concentration of blood urea nitrogen in this study was much higher than that was reported in England, U.S.A. and Japan, and it was similar to the upper limits reported in England, U.S.A. and Japan. So it was thought that the concentration of blood urea nitrogen is improper as a criteria for protein intake. The increase of serum total protein cocentration beyond standard limits was due to increase of serum globulin concentration in most of the cows. The correlation coefficient between serum and protein and serum globulin concentration was 0.83. Serum globulin concentration was negatively related to adjusted corrected milk of herd. Serum albumin, calcium and magnessium concentrations were negatively related to adjusted corrected milk of herd, which indicate that high-producing individual or high-producing herd have not taken sufficient protein/amino acids, calcium and magnessium. Packed cell volume was negatively related to adjusted corrected milk of the herd, and the trend was same In each lactational stage. The correlation coefficient between serum and packed cell volume was 0.16 and the correlation was very weak. Blood glucose concentration was lowest in early lactational stage, which indicates negative energy balance in early lactational stage. Blood glucose concentration was negatively related to adjusted corrected milk of herd from peak to late lactational stage, which indicates negative energy balance during the period in high-producing individuals or high-producing herds. Correlation coefficient between serum aspartate aminotransferase activity and serum ${\gamma}$-glutamyltransferase activity was 0.41, and this indicates that serum ${\gamma}$-glutamyltransferase should be included as a parameter of metabolic profile test to evaluate liver function. Body condition score of dairy cows in this country was lower than that of Japan in every lactational stages, and the magnitude of increase in body condition score during middle and late lactational stages was small. Metabolic profile can not be evaluated with solely nutritional intake. When an individual or large percentage of cows in a herd have adnormal values In parameters of metabolic profile test, veterinary clinician and nutritionist should cooperate so as to diagnose diseases and to calculate the e of no운ents simultaneously.

• Journal of Intelligence and Information Systems
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• v.19 no.1
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• pp.111-123
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• 2013

Semantic similarity/relatedness measure between two concepts plays an important role in research on system integration and database integration. Moreover, current research on keyword recommendation or tag clustering strongly depends on this kind of semantic measure. For this reason, many researchers in various fields including computer science and computational linguistics have tried to improve methods to calculating semantic similarity/relatedness measure. This study of similarity between concepts is meant to discover how a computational process can model the action of a human to determine the relationship between two concepts. Most research on calculating semantic similarity usually uses ready-made reference knowledge such as semantic network and dictionary to measure concept similarity. The topological method is used to calculated relatedness or similarity between concepts based on various forms of a semantic network including a hierarchical taxonomy. This approach assumes that the semantic network reflects the human knowledge well. The nodes in a network represent concepts, and way to measure the conceptual similarity between two nodes are also regarded as ways to determine the conceptual similarity of two words(i.e,. two nodes in a network). Topological method can be categorized as node-based or edge-based, which are also called the information content approach and the conceptual distance approach, respectively. The node-based approach is used to calculate similarity between concepts based on how much information the two concepts share in terms of a semantic network or taxonomy while edge-based approach estimates the distance between the nodes that correspond to the concepts being compared. Both of two approaches have assumed that the semantic network is static. That means topological approach has not considered the change of semantic relation between concepts in semantic network. However, as information communication technologies make advantage in sharing knowledge among people, semantic relation between concepts in semantic network may change. To explain the change in semantic relation, we adopt the cognitive semantics. The basic assumption of cognitive semantics is that humans judge the semantic relation based on their cognition and understanding of concepts. This cognition and understanding is called 'World Knowledge.' World knowledge can be categorized as personal knowledge and cultural knowledge. Personal knowledge means the knowledge from personal experience. Everyone can have different Personal Knowledge of same concept. Cultural Knowledge is the knowledge shared by people who are living in the same culture or using the same language. People in the same culture have common understanding of specific concepts. Cultural knowledge can be the starting point of discussion about the change of semantic relation. If the culture shared by people changes for some reasons, the human's cultural knowledge may also change. Today's society and culture are changing at a past face, and the change of cultural knowledge is not negligible issues in the research on semantic relationship between concepts. In this paper, we propose the future directions of research on semantic similarity. In other words, we discuss that how the research on semantic similarity can reflect the change of semantic relation caused by the change of cultural knowledge. We suggest three direction of future research on semantic similarity. First, the research should include the versioning and update methodology for semantic network. Second, semantic network which is dynamically generated can be used for the calculation of semantic similarity between concepts. If the researcher can develop the methodology to extract the semantic network from given knowledge base in real time, this approach can solve many problems related to the change of semantic relation. Third, the statistical approach based on corpus analysis can be an alternative for the method using semantic network. We believe that these proposed research direction can be the milestone of the research on semantic relation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.1-2
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• 2011

Hybrid rockets have lately attracted attention as a strong candidate of small, low cost, safe and reliable launch vehicles. A significant topic is that the first commercially sponsored space ship, SpaceShipOne vehicle chose a hybrid rocket. The main factors for the choice were safety of operation, system cost, quick turnaround, and thrust termination. In Japan, five universities including Hokkaido University and three private companies organized "Hybrid Rocket Research Group" from 1998 to 2002. Their main purpose was to downsize the cost and scale of rocket experiments. In 2002, UNISEC (University Space Engineering Consortium) and HASTIC (Hokkaido Aerospace Science and Technology Incubation Center) took over the educational and R&D rocket activities respectively and the research group dissolved. In 2008, JAXA/ISAS and eleven universities formed "Hybrid Rocket Research Working Group" as a subcommittee of the Steering Committee for Space Engineering in ISAS. Their goal is to demonstrate technical feasibility of lowcost and high frequency launches of nano/micro satellites into sun-synchronous orbits. Hybrid rockets use a combination of solid and liquid propellants. Usually the fuel is in a solid phase. A serious problem of hybrid rockets is the low regression rate of the solid fuel. In single port hybrids the low regression rate below 1 mm/s causes large L/D exceeding a hundred and small fuel loading ratio falling below 0.3. Multi-port hybrids are a typical solution to solve this problem. However, this solution is not the mainstream in Japan. Another approach is to use high regression rate fuels. For example, a fuel regression rate of 4 mm/s decreases L/D to around 10 and increases the loading ratio to around 0.75. Liquefying fuels such as paraffins are strong candidates for high regression fuels and subject of active research in Japan too. Nakagawa et al. in Tokai University employed EVA (Ethylene Vinyl Acetate) to modify viscosity of paraffin based fuels and investigated the effect of viscosity on regression rates. Wada et al. in Akita University employed LTP (Low melting ThermoPlastic) as another candidate of liquefying fuels and demonstrated high regression rates comparable to paraffin fuels. Hori et al. in JAXA/ISAS employed glycidylazide-poly(ethylene glycol) (GAP-PEG) copolymers as high regression rate fuels and modified the combustion characteristics by changing the PEG mixing ratio. Regression rate improvement by changing internal ballistics is another stream of research. The author proposed a new fuel configuration named "CAMUI" in 1998. CAMUI comes from an abbreviation of "cascaded multistage impinging-jet" meaning the distinctive flow field. A CAMUI type fuel grain consists of several cylindrical fuel blocks with two ports in axial direction. The port alignment shifts 90 degrees with each other to make jets out of ports impinge on the upstream end face of the downstream fuel block, resulting in intense heat transfer to the fuel. Yuasa et al. in Tokyo Metropolitan University employed swirling injection method and improved regression rates more than three times higher. However, regression rate distribution along the axis is not uniform due to the decay of the swirl strength. Aso et al. in Kyushu University employed multi-swirl injection to solve this problem. Combinations of swirling injection and paraffin based fuel have been tried and some results show very high regression rates exceeding ten times of conventional one. High fuel regression rates by new fuel, new internal ballistics, or combination of them require faster fuel-oxidizer mixing to maintain combustion efficiency. Nakagawa et al. succeeded to improve combustion efficiency of a paraffin-based fuel from 77% to 96% by a baffle plate. Another effective approach some researchers are trying is to use an aft-chamber to increase residence time. Better understanding of the new flow fields is necessary to reveal basic mechanisms of regression enhancement. Yuasa et al. visualized the combustion field in a swirling injection type motor. Nakagawa et al. observed boundary layer combustion of wax-based fuels. To understand detailed flow structures in swirling flow type hybrids, Sawada et al. (Tohoku Univ.), Teramoto et al. (Univ. of Tokyo), Shimada et al. (ISAS), and Tsuboi et al. (Kyushu Inst. Tech.) are trying to simulate the flow field numerically. Main challenges are turbulent reaction, stiffness due to low Mach number flow, fuel regression model, and other non-steady phenomena. Oshima et al. in Hokkaido University simulated CAMUI type flow fields and discussed correspondence relation between regression distribution of a burning surface and the vortex structure over the surface.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.6
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• pp.256-268
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• 2016

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2015. 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 were carried out in the areas of flow, heat and mass transfer, cooling and heating, and air-conditioning, the renewable energy system and the flow inside building rooms. Research issues dealing with air-conditioning machines and fire and exhausting smoke were reduced. CFD seems to be spreading to more research areas. (2) Research works on heat transfer area were carried out in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the economic analysis of GHG emission, micro channel heat exchanger, effect of rib angle on thermal performance, the airside performance of fin-and-tube heat exchangers, theoretical analysis of a rotary heat exchanger, heat exchanger in a cryogenic environment, the performance of a cross-flow-type, indirect evaporative cooler made of paper/plastic film. In the area of pool boiling and condensing, the bubble jet loop heat pipe was studied. In the area of industrial heat exchangers, researches were performed on fin-tube heat exchanger, KSTAR PFC and vacuum vessel at baking phase, the performance of small-sized dehumidification rotor, design of gas-injection port of an asymmetric scroll compressor, effect of slot discharge-angle change on exhaust efficiency of range hood system with air curtain. (3) In the field of refrigeration, various studies were carried in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, a cold-climate heat pump system, $CO_2$ cascade systems, ejector cycles and a PCM-based continuous heating system were investigated. In the alternative refrigeration/energy system category, a polymer adsorption heat pump, an alcohol absorption heat pump and a desiccant-based hybrid refrigeration system were investigated. In the system control category, turbo-refrigerator capacity controls and an absorption chiller fault diagnostics were investigated. (4) In building mechanical system research fields, eighteen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping 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 was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the user and location awareness technology applied dimming lighting control system, the lighting performance evaluation for light-shelves, the improvement evaluation of air quality through analysis of ventilation efficiency and the evaluation of airtightness of sliding and LS window systems. The subjects of building energy were worked on the energy saving estimation of existing buildings, the developing model to predict heating energy usage in domestic city area and the performance evaluation of cooling applied with economizer control. The studies were also performed related to the experimental measurement of weight variation and thermal conductivity in polyurethane foam, the development of flame spread prevention system for sandwich panels, the utilization of heat from waste-incineration facility in large-scale horticultural facilities.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.2
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• pp.103-109
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• 2016

Efficacy of cosmetics has been mainly evaluated by qualitative and quantitative methods based on visual sense, tactile sense and skin structure until now. In this study, we suggested a novel evaluation method for skin status based on sound; measuring and analyzing the rubbing noise generated by applying cosmetics. First, the rubbing noise was measured at a close range by a high-sensitivity microphone in anechoic environment, and the noises were analyzed by 1/3 octave band analysis in frequency-domain. Three conditions, 1) before washing, 2) after washing and 3) after application of cosmetics, were compared. As a result, sound pressure level (SPL) of rubbing noise after washing was larger than that of before washing, and the SPL of rubbing noise after cosmetic application was the smallest. Furthermore, the energy of rubbing noise after application was higher than that of the before and after washing conditions in a low frequency band (lower than 2 kHz region). Conversely, the energy of rubbing noise after application was much lower than the others in a high-frequency band (upper than 2 kHz region). This change of energy distribution was described as a balloon-skin model. High SPL in the low frequency region after the cosmetic applications was due to the increase of "flexibility index", while SPL in the high frequency region significantly decreased because of the attenuation which is related to "softness index". Therefore, we developed two indices based on the spectrum-energy difference for evaluating skin conditions. This proposed method and indices were verified via skin flexibility and roughness measurement using cutometer and primos respectively. These results suggest that acoustic measurement of skin friction noise may be a new skin status evaluation method.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.630-647
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• 2021

We determined the current problem of the restoration deposit-estimation system, stipulated by the Mountainous Districts Management Act, using the Delphi technique. Consequently, we proposed a standard model for forest land restoration to derive a reasonable deposit-estimation system. With the result of the Delphi survey, the inappropriateness of land-use type and slope gradient classifications was shown; the insufficiency of standard works was a significant problem in the current system. A way to solve these problems was devised, to reorganize the current land-use type into the subject of the site. The specific subjects included the following: (i) to permit or report forest land-use change and temporary use of forest land, (ii) to report temporary use of forest land, (iii) to permit stone collection or sale for mineral mining, and (iv) to allow sediment collection. The current slope gradient subdivision into (a) θ<10°, (b) 10°≦θ<15°, (c) 15°≦θ<20°, (d) 20°≦θ<25°, (e) 25°≦θ<30°, and (f) θ≧30° and the reorganization of 17 standard works into 22 standard works were deemed as solutions, along with seven additional works. We developed 24 standard models for the forest land restoration project based on the aforementioned results. The deposits estimated by these models ranged from 34,185,000 (Korean) won to 607,403,000 won. If additional works, premiums, discounts, and supervision fees are added to the models, the deposit increases to an estimated 668,143,000 won subject to permission for stone collection or sale and mineral mining. Experts agree on the distribution of the restoration deposits estimated by these models at a high level in the Delphi survey. Our findings are expected to contribute to securing the appropriateness of the restoration cost deposited for the smooth performance of the vicariously executed restoration project.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.2
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• pp.88-99
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• 2019

This study aims to conduct a depth analysis of motivation and value of local residents and tourists based on means-end chain theory. The sampling of the study was conducted on local residents living near downtown area of Gyeong-ju City, and tourists through soft laddering and hard laddering methods. A mutual correlation model in relation with Hierarchical Value Map (HVM) for each group by conducting the analysis of factor loading (attributes, consequences, value) and cognitive structure (the correlations among attributes, consequences and value) was proposed and the comparisons of HVM for each group was also conducted. The structured questionnaires using Association Pattern Technique (APT) of hard laddering were utilized to analyze the means and end of value chain structures in terms of the attributes, consequences, value of Gyeong-ju Ancient Tombs. The findings propose that local residents are visiting Ancient Tombs Gyeong-ju City Center for 'Rest and take a walk' as the means, which results in 'Relieving stress' and eventually leads to the 'Improvement of historic and cultural cultivation' as the end. On the other hand, tourists also 'Rest and take a walk' as the mean, which also leads to 'Relieving stress'. However, unlike local residents, it eventually leads to 'Self-reflection and healing' as the end. It is expected that the findings of this study not only recommend us to consider preserving and managing cultural heritages and value of ancient tombs in developing "Ancient Tomb Park in Gyoneg-ju City Center" but also provides baseline data for the establishment of reasonable plans of utilizing tombs, historical and cultural heritages.