• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.7
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• pp.492-507
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• 2010

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2009. 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) Research trends of thermal and fluid engineering have been surveyed as groups of general thermal and fluid flow, fluid machinery and piping, and new and renewable energy. Various topics were covered in the field of general thermal and fluid flow such as an expander, a capillary tube, the flow of micro-channel water blocks, the friction and anti-wear characteristics of nano oils with mixtures of refrigerant oils, etc. Research issues mainly focused on the design of micro-pumps and fans, the heat resistance reliability of axial smoke exhaust fans, and hood systems in the field of fluid machinery and piping. Studies on ground water sources were executed concerning two well type geothermal heat pumps and multi-heat pumps in the field of new and renewable energy. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics and industrial heat exchangers. Researches on heat transfer characteristics included the heat transfer in thermoelectric cooling systems, refrigerants, evaporators, dryers, desiccant rotors. In the area of industrial heat exchangers, researches on high temperature ceramic heat exchangers, plate heat exchangers, frosting on fins of heat exchangers were performed. (3) In the field of refrigeration, papers were presented on alternative refrigerants, system improvements, and the utilization of various energy sources. Refrigeration systems with alternative refrigerants such as hydrocarbons, mixed refrigerants, and $CO_2$ were studied. Efforts to improve the performance of refrigeration systems were made applying various ideas of suction line heat exchangers, subcooling bypass lines and gas injection systems. Studies on heat pump systems using unutilized energy sources such as river water, underground water, and waste heat were also reported. (4) Research trend in the field of mechanical building facilities has been found to be mainly focused on field applications rather than performance improvements. In the area of cogeneration systems, papers on energy and economic analysis, LCC analysis and cost estimating were reported. Studies on ventilation and heat recovery systems introduced the effect on fire and smoke control, and energy reduction. Papers on district cooling and heating systems dealt with design capacity evaluation, application plan and field application. Also, the maintenance and management of building service equipments were presented for HVAC systems. (5) In the field of architectural environment, various studies were carried to improve indoor air quality and to analyze the heat load characteristics of buildings by energy simulation. These studies helped to understand the physics related to building load characteristics and to improve the quality of architectural environment where human beings reside in.

• Journal of the Korean Wood Science and Technology
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• v.38 no.3
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• pp.230-241
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• 2010

The purpose of this study was to seek the optimum condition for effective separation of the chemical constituents of wood biomass by means of hydrolysis of acetone solution in presence of acid salt as a catalyst. Out of diverse acid salts the catalytic effect of aluminum sulfate ($Al_2(SO_4)_3$) was the most excellent during the hydrolysis of wood biomass in the acetone solution and the optimum concentration was 0.01 M (6.3 wt%). In the condition of mixture ratio of acetone and water to 9 : 1 as well as optimum concentration of aluminum sulfate two wood biomass species, oak wood (Quercus mongolica Fischer) and Pine wood (Pinus densiflora Sieb. et Zucc.), was hydrolyzed for 45 minutes at $200^{\circ}C$ and the degree of hydrolysis was determined to 92.7% and 92.4%, respectively. Extending the reaction time to 60 minutes in the mixture ratio of acetone and water to 8 : 2 the degree of hydrolysis of oak wood was also ca. 92.7%. In the case of Pinus, however, the similar hydrolysis ratio was obtained at $210^{\circ}C$. As the temperature and hydrolysis time increased, the quantitative amount of lignin recovered from the hydrolysate clearly increased, whereas the total amount of carbohydrates in the hydrolysate decreased rapidly. Considering the recoverable amount of lignin and carbohydrate in the hydrolysate, the best condition for the hydrolysis of wood biomasses were confirmed to the mixture ratio of acetone and water to 8 : 2, the concentration of aluminum sulfate of 6.3 wt%, hydrolysis temperature of $190^{\circ}C$ for 60 minutes. In this condition the total amounts of carbohydrate in the hydrolysates of oak wood and pine wood were estimated to 47.6% and 51.4%, respectively. The amount of lignin recovered from the hydrolysates were ca. 18.2% for oak wood and 13.7% for pine wood.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.1
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• pp.30-35
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• 2013

Purpose: One of the current services, providing information to the patients and their guardians by using promotion materials induces positive responses and contributes to the improvement of the hospital reliability. Therefore, the objective of this study is to evaluate the effectiveness of audio visual materials, one of the means of promotion, as a way to give accurate medical information to resolve patient's curiosity about purpose and procedure of their examination and deplete complains about waiting which attributes negative effect to service quality assessment. Materials and Methods: 60 patients(mean age $53.97{\pm}12.24$, male : female = 26 : 34) who had $^{18}F-FDG PET/CT$ scan from July 2012 to August 2012 in Seoul Asan Medical Center were referred to the study. All of the patients having PET/CT scan were asked to watch an informative video material before the injection of radiopharmaceutical ($^{18}F-FDG$) and to fill in a questionnaire. Results: As a result of analyzing the contents of questionnaire, 52% of 60 patients had PET/CT scan for the first time and 72.4% of the patients read the PET/CT guidebook offered from their outpatient department or inpatient wards before their scan. After we searched the level of previous knowledge of the purpose and method of PET/CT scan, the patients answered 25.1% "know well", 34% "not sure", 40.9% "don't know" respectively. And 84.7% of the patients answered that watching the PET/CT guide video before the injection helps understanding what exam they were having and 15.3% of the patients did not. For the question asking ever the patients have experienced using our homepage or smart phone QR code to see the guide video before they visit out PET center, only 3.3% of them answered "yes". Lastly, the patients answered 60.1% "yes", 31.4% "so so" and 8.5% "no" respectively for the question asking whether watching the video makes the patients to fill the waiting time short. Conclusion: It is found that understanding of objective and method of the PET/CT scan and level of satisfaction was improved after the patients watched the guide video whether they had PET/CT scan before and read the PET/CT guidebook or not. Also, watching the video was effective for the reduction of perceptible waiting time. But while displaying the PET/CT guide video is useful for providing information about the scan and shortening the waiting time as one of the medical service, utilization of service was actually very poor because of the passive promotion and indifference of the patients about their examination. Therefore, from now on, it is necessary to construct the healthcare system which can be offered to more patients through the active promotion.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.3
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• pp.241-258
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• 1998

The experimental demersal trawl surveys to provide the essential information for the assessment, management and utilization of commercially important fish stocks in the southern waters of Korea were carried out during five research cruises between October 1996 and October 1997 by the training ship “KAYA” of Pukyong National University. The biological sampling was conducted by using the trawl net with a cover net of 36 mm in mesh size at 64 planned trawl stations during daylight to identify the biological characteristics of fish. Each catch was standardized into catch per unit of time and the catches at each trawl station were sorted, weighed and counted by species. The changes in catches of each fish species and the shifts in dominant species by seasions and sampling regions in the research area were analyzed, and the abundance of fish was estimated from the relationship between the trawl catches and the volume of the water column sampled by demersal trawls. The results obtained can be summarized as follows : 1. During the 64 demersal trawls conducted in the southern waters of Korea, 129 species including 112 species of fishes, 8 species of Cephalopoda and 7 species of Crustacea, were identified Also, during the 1996 and 1997 trawl surveys in the reseach area, a large number of commercially important species with small differences in proportion was found. me proportion of Japanese horse mackerel which comprised 19.8% of the total catch by weight was highest, followed by chub mackerel(15.0%), swordtip squid(9.0%), redwing searobin(6.2%), konoshiro gizzard shad(6.1%), Japanese flying squid(5.8%), silver pomfet(5.1%), blackmouth goosefish(5.1%), etc. Swordtip squid, Japanese flying squid, blackmouth goosefish and blackthroat seaperch were among the dominant species in all seasons with a relatively high and stab1e proportion(3.6~9.0%), and were widely distributed in the entire southern water of Korea. 2. The catch rates by cover net varied at 0.7~91.9% by weight of the total trawl catch by codend and cover net at 64 planned trawl stations and the mean catch rate was 44.4%. Species comprising a major portion of the catches by cover net mainly were swordtip squid, konoshiro gizzard shad, the juveniles of Japanese horse mackerel, blackthroat seaperch and chub mackerel, etc. 3. The distribution density of fish in terms of biomass per unit volume which derived from the catch data by 63 bottom trawl hauls in the southern waters of Korea ranged from 17.9 $\times$ 10-6 to 1,440.9 $\times$ 10-6kg/m3 with the mean value of 153.8 $\times$ 10-6 kg/m3. These fish densities varied between seasons, location of sampling stations and sea conditions. From these results, it is worth noting that the catch composition of multispecies and the increased occurrence of small fish in the southern waters of Korea may also result in new problems in determining the total allowable catch(TAC) levels for economically important species.

• Journal of Intelligence and Information Systems
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• v.24 no.2
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• pp.21-35
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• 2018

Since the introduction of MP3 players, CD recordings have gradually been vanishing, and the music consuming environment of music users is shifting to mobile devices. The introduction of smart devices has increased the utilization of music through music playback, mass storage, and search functions that are integrated into smartphones and tablets. At the time of initial MP3 player supply, the bitrate of the compressed music contents generally was 128 Kbps. However, as increasing of the demand for high quality music, sound quality of 384 Kbps appeared. Recently, music content of FLAC (Free License Audio Codec) format using lossless compression method is becoming popular. The download service of many music sites in Korea has classified by unlimited download with technical protection and limited download without technical protection. Digital Rights Management (DRM) technology is used as a technical protection measure for unlimited download, but it can only be used with authenticated devices that have DRM installed. Even if music purchased by the user, it cannot be used by other devices. On the contrary, in the case of music that is limited in quantity but not technically protected, there is no way to enforce anyone who distributes it, and in the case of high quality music such as FLAC, the loss is greater. In this paper, the author proposes an audio watermarking technology for copyright protection of high quality stereo music. Two kinds of information, "Copyright" and "Copy_free", are generated by using the turbo code. The two watermarks are composed of 9 bytes (72 bits). If turbo code is applied for error correction, the amount of information to be inserted as 222 bits increases. The 222-bit watermark was expanded to 1024 bits to be robust against additional errors and finally used as a watermark to insert into stereo music. Turbo code is a way to recover raw data if the damaged amount is less than 15% even if part of the code is damaged due to attack of watermarked content. It can be extended to 1024 bits or it can find 222 bits from some damaged contents by increasing the probability, the watermark itself has made it more resistant to attack. The proposed algorithm uses quantization in DCT so that watermark can be detected efficiently and SNR can be improved when stereo music is converted into mono. As a result, on average SNR exceeded 40dB, resulting in sound quality improvements of over 10dB over traditional quantization methods. This is a very significant result because it means relatively 10 times improvement in sound quality. In addition, the sample length required for extracting the watermark can be extracted sufficiently if the length is shorter than 1 second, and the watermark can be completely extracted from music samples of less than one second in all of the MP3 compression having a bit rate of 128 Kbps. The conventional quantization method can extract the watermark with a length of only 1/10 compared to the case where the sampling of the 10-second length largely fails to extract the watermark. In this study, since the length of the watermark embedded into music is 72 bits, it provides sufficient capacity to embed necessary information for music. It is enough bits to identify the music distributed all over the world. 272 can identify $4*10^{21}$, so it can be used as an identifier and it can be used for copyright protection of high quality music service. The proposed algorithm can be used not only for high quality audio but also for development of watermarking algorithm in multimedia such as UHD (Ultra High Definition) TV and high-resolution image. In addition, with the development of digital devices, users are demanding high quality music in the music industry, and artificial intelligence assistant is coming along with high quality music and streaming service. The results of this study can be used to protect the rights of copyright holders in these industries.

• Korean Journal of Agricultural Science
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• v.9 no.1
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• pp.357-370
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• 1982

Recent concern regarding price and availability of fossil fuels has spurred the interest in alternative sources for farm crop drying. Among the available options such as biomass energy, wind power, nuclear energy and solar energy etc., the increasing attention is being directed to the utilization of heat from solar energy especially for farm crop drying. Even though solar energy is dispersed over a large land area and only a relatively small amount of energy can be simply collected, the advantages of solar energy is that the energy is free, non-polluting. The study reported here was designed to help supply the informations for the development of simple and relatively inexpensive solar warehouse for farm crop drying and storage. Specifically, the objectives of this study were to determine the performance of the solar collector fabricated, to compare solar supplemented heat drying with natural air drying and to develop a simulation model of temperature in stored grain, which can be used to study the effects due to changes in ambient air temperature. For those above objectives, solar collector was fabricated from available materials. Corrugated steel galvanized sheet, painted flat black, was used as absorbers and clear 0.2mm polyethylene sheet was the cover material. The warehouse for rough rice drying and storage was constructed with concrete block, and the solar collector was used as the roof of warehouse instead of original roofing system of it. The results obtained in this study were as follows: 1. The thermal efficiency of the solar collector was average 26 percent and the overall heat transfer coefficient of the collector was approximately $25kJ/hr.m^2\;^{\circ}K$. 2. Solar heated air was sufficient to dry one cubic meter of rough rice from 23.5 to 15.0 percent in 7 days and natural air was able to dry the same amount of rough rice from 20.0 to 5 percent in l2 days. 3. Drying with solar heat reduced the required drying time to dry the same amount of rough rice into a half compared to natural air drying, but overdrying problems of the bottom layer were so severe that these problems should be thoroughly analyzed. 4. Simulation model of temperature in stored grain was developed and the results of predicted temperature agreed well with test results. 5. Based on those simulated temperature, changes in the grain-temperature were a large at the points of the wallside and the damage of the grain would be severe at the contact area of wall.

• Korean Journal of Food Science and Technology
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• v.10 no.1
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• pp.73-77
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• 1978

This experiment was made to select the optimum thickness of the polyethylene (P.E) film for Cheongdo Bansi and Sagoksi in the P.E film storage kept at $0^{\circ}C$. The experimental plots were divided into 4 plots by film thickness (0.04, 0.06, 0.08 and 0.10mm) and those were subdivided into 3 plots by fruits number (3, 10 and 50 persimmons) in each film bags. We investigated five experimental items; the change of loss of weight, firmness, titratable acidity, sugar contents and soluble tannin contents. 1. In the changes of loss of weight, the plot of packing in 0.04mm P.E. film bag with 50 persimmons were more retarded than other plots in Cheongdo Bansi, and packing in 0.08mm with 10 persimmons, 0.04 mm with 50 persimmons were more retarded than other plots in Sagoksi. 2. In the change of softening, the plot of packing in 0.04 mm with 50 persimmons were more retarded than other plots in Cheongdo Bansi and Sagkai. 3. In the changes of titratable acidity, the plot of packing in 0.04 mm with 50 persimmons were more slightly decreased than other plots in Cheongdo Bansu also in Sagoksi, packing in 0.06 mm with 10 persimmons were the same results. 4. In the changes of soluble tannin contents, the plots of packing in 0.06 mm with 10 persimmons, 0.04 mm with 50 perimmons were more ratarded in Chenongdo Bansi, also in Sagoksi, packing in 0.04 mm with 10 persimmons 50 persimmons were the same results. 5. In the changes of soluble tannin contents, the plots of packing in 0.04mm with 3 and 10 persimmons were more slowly decreased than other plots in Cheongdo Bansi and Sagoksi, on. the other hand, pcaking in 0.04mm with 50 persimmins in Cheongdo Bansi and Sagoksi, had not astringent taste at 120 days in storage. Judging through the upper results, the most desirable storage conditions for Cheongdo Bansi and Sagoksi were to pack in P.E film bag of 0.04mm with 50 persimmons.

• Journal of Life Science
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• v.18 no.9
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• pp.1186-1193
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• 2008

The growth performance of pangasiid catfish (Pangasius hypophthalmus), silver carp (Hypophthalmichthys molitrix) and catla (Catla catla) was evaluated in polyculture at varied combinations and stocking ratios in earthen pond for a period of 16 weeks. Combinations of pangasiid catfish, silver carp and catla with the total density of 30,000 fish per hectare were evaluated. A commercial pelleted feed containing 28% crude protein and 6% lipid was fed only to pangasiid catfish at the rate of 8% of body weight during the first six weeks, 6% during the second six weeks and 4% thereafter twice daily. The growth and feed utilization efficiency of pangasiid catfish were found similar in all treatments. The growth of silver carp was markedly decreased upon the increase of its own stocking density. The highest growth of silver carp achieved in polyculture of pangasiid catfish, silver carp and catla at 2:1:1 ratio where density of silver carp was lowest. The growth of catla was found to be affected by the presence of silver carp. The growth rate of catla markedly declined with the increase of silver carp density. The highest growth of catla obtained in polyculture of pangasiid catfish only with catla stocked at 1:1 ratio. The highest yield and economic return achieved in polyculture of pangasiid catfish, silver carp and catla at the ratio of 2:1:1 due to higher growth of silver carp and higher market value of catla. The water quality conditions in all different treatment ponds were within optimum ranges throughout the culture period and the values did not show any significant variation (p>0.05) among the treatments.

• Asia pacific journal of information systems
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• v.23 no.2
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• pp.21-39
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• 2013

As the utilization of information technology and the turbulence of technological change increase in organizations, the adoption of IT outsourcing also grows to manage IT resource more effectively and efficiently. In this new way of IT management technique, service level management(SLM) process becomes critical to derive success from the outsourcing in the view of end users in organization. Even though much of the research on service level management or agreement have been done during last decades, the performance of the service level management process have not been evaluated in terms of final objectives of the management efforts or success from the view of end-users. This study explores the relationship between SLM maturity and IT outsourcing success from the users' point of view by a analytical case study in four client organizations under an IT outsourcing vendor, which is a member company of a major Korean conglomerate. For setting up a model for the analysis, previous researches on service level management process maturity and information systems success are reviewed. In particular, information systems success from users' point of view are reviewed based the DeLone and McLean's study, which is argued and accepted as a comprehensively tested model of information systems success currently. The model proposed in this study argues that SLM process maturity influences information systems success, which is evaluated in terms of information quality, systems quality, service quality, and net effect proposed by DeLone and McLean. SLM process maturity can be measured in planning process, implementation process and operation and evaluation process. Instruments for measuring the factors in the proposed constructs of information systems success and SL management process maturity were collected from previous researches and evaluated for securing reliability and validity, utilizing appropriate statistical methods and pilot tests before exploring the case study. Four cases from four different companies under one vendor company were utilized for the analysis. All of the cases had been contracted in SLA(Service Level Agreement) and had implemented ITIL(IT Infrastructure Library), Six Sigma and BSC(Balanced Scored Card) methods since last several years, which means that all the client organizations pursued concerted efforts to acquire quality services from IT outsourcing from the organization and users' point of view. For comparing the differences among the four organizations in IT out-sourcing sucess, T-test and non-parametric analysis have been applied on the data set collected from the organization using survey instruments. The process maturities of planning and implementation phases of SLM are found not to influence on any dimensions of information systems success from users' point of view. It was found that the SLM maturity in the phase of operations and evaluation could influence systems quality only from users' view. This result seems to be quite against the arguments in IT outsourcing practices in the fields, which emphasize usually the importance of planning and implementation processes upfront in IT outsourcing projects. According to after-the-fact observation by an expert in an organization participating in the study, their needs and motivations for outsourcing contracts had been quite familiar already to the vendors as long-term partners under a same conglomerate, so that the maturity in the phases of planning and implementation seems not to be differentiating factors for the success of IT outsourcing. This study will be the foundation for the future research in the area of IT outsourcing management and success, in particular in the service level management. And also, it could guide managers in practice in IT outsourcing management to focus on service level management process in operation and evaluation stage especially for long-term outsourcing contracts under very unique context like Korean IT outsourcing projects. This study has some limitations in generalization because the sample size is small and the context itself is confined in an unique environment. For future exploration, survey based research could be designed and implemented.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.1
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• pp.10-19
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• 2000

Due to the urbanization, concentrated population, and limited land exploitation in the modern society, the environment surrounding that we live in is getting polluted more and more, and it has become hard even to let urban children experience the nature. This research was conducted to help people recognize the importance of our natural resources through the environmental education of elementary school and to use school's practical open-space for the Indigenous Plants education. The results of this study are as follows : First, the status of a plant utilization in our institutional education : There were 362 species totally of 124 species of Trees, 156 species of Herbs, 63 species of Crops, and 19 species of Hydrophytes which appear in the elementary school text book. Of all, the most frequently appearing species of tree were the Malus pumila var. dulcissima, Pinus densijlora, Citrus unshiu, Diospyros kaki. Second, the effect of plant education using the land around schools : The result of research on the open-space of the 19 elementary schools located in Mapo-gu showed that most of the species planted are the Juniperus chinensisrose, Hibiscus syriacus. Pelargonium inquinans in the order of size, and the plants appearing in text book were grown in the botanical garden organized in 7 schools. Especially most of the Indigenous Plants were being planted in botanical garden, and Pinus densijlora, Abeliophyllum distichum, Polygonatum var. plurijlorum, Liriope platyphylla and so on. Last, the result of this research on recognition of Environment, Planting education and Indigenous plants : It showed that educational necessity of students and teachers about environment and Indigenous Plants was more than 80%. The management of botanical garden was conducted by some teachers and managers. The results of this study suggested that we needed the reconstruction of curriculum, the efficient application of plant education for effectiveness of using school environment and monitoring continually and construction information sources for the better environment education in the elementary schools.