• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.2
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• pp.49-58
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• 2008

Generally, steel corrosion occurs in concrete structures due to carbonation in down-town area and underground site and it propagates to degradation of structural performance. In general diagnosis and inspection, only carbonation depth in sound concrete is evaluated but unsound concrete such as joint and cracked area may occur easily in a concrete member due to construction process. In this study, field survey of carbonation for RC columns in down-town area is performed and carbonation depth in joint and cracked concrete including sound area is measured. Probability of durable failure with time is calculated through probability variables such as concrete cover depth and carbonation depth which are obtained from field survey. In addition, service life of the structures is predicted based on the intended probability of durable failure in domestic concrete specification. It is evaluated that in a RC column, various service life is predicted due to local condition and it is rapidly decreased with insufficient cover depth and growth of crack width. It is also evaluated that obtaining cover depth and quality of concrete is very important because the probability of durable failure is closely related with C.O.V. of cover depth.

• Journal of Food Hygiene and Safety
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• v.39 no.1
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• pp.26-34
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• 2024

In this study, the food service management levels of cafeterias in childcare facilities were investigated based on the number of meal recipients and the working status of the kitchen staff. The study included 199 childcare facilities nationwide that received food supplies from the food ingredients distribution company, Pulmuone Foodmerce, from 2021 to 2022. The assessment was conducted using 61 inspection items. The analysis revealed that, as the number of meal recipients and kitchen staff members decreased, the documentation of inspection results was less likely to be conducted (P<0.05). Facilities with fewer meal recipients showed less adequate health status checks for kitchen staff, and those with fewer kitchen staff showed insufficient compliance with hygienic clothing (P<0.05). Additionally, facilities with fewer meal recipients showed a higher frequency of lapses in checking the expiration dates of stored ingredients (P<0.05), requiring increased management attention. They also exhibited the absence of internal temperature measurement records during heating processes (P<0.05). Furthermore, facilities with fewer meal recipients demonstrated inadequate maintenance of kitchen facilities (P<0.05). Significantly higher adenosine triphosphate (ATP) levels were detected on the hands and cutting boards of the kitchen staff in facilities with fewer meal recipients and fewer kitchen staff (P>0.05). Overall, facilities with fewer meal recipients exhibited insufficient infrastructure management for kitchen operations and inadequate hygiene management. These results are expected to provide foundational data for the selection of national support programs for childcare facilities in the future.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.5
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• pp.1-8
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• 2014

Structures requiring chemical resistance are usually coated with surface protecting agents, but the cost for maintenance and re-construction is incurred due to the low durability. Therefore, in this study, sulfur was polymerized and the performance was examined so that it could be used as the concrete surface protecting agents for structures requiring chemical resistance. The evaluation results indicated that for the spray of the sulfur polymer surface coating agents, the application of the gravity type was appropriate; and for the number of coating times, about 3 cycle spray gave the best results. For the surface condition of the concrete to be coated with the surface protecting agents, outstanding quality was obtained above room temperature ($20{\sim}30^{\circ}C$), and the bond strength increased as the temperature increased. The evaluation results of the strength characteristics depending on the filler content of the surface protecting agents indicated that about 20~40% filler mixing contributed to the strength improvement as it reduced the shrinkage of the sulfur polymer. Also, the mixing of silica showed larger increase in the bond strength than the mixing of fly ash, and the most outstanding bond strength characteristics could be obtained by the mixing of both silica and fly ash. In the case of the chemical resistance, the strength reduction was minimized and outstanding chemical resistance was obtained when the fly ash and silica were substituted by 20%, respectively. The performance evaluation of the chloride ion penetration indicated that for the specimens coated with the sulfur polymer surface protecting agents, the chloride ion penetration resistance increased by 29~48% compared to the specimen without the coating of the surface protecting agent. The examination of the coating condition of the surface protecting agents, compressive strength, bond strength, chemical resistance, and salt damage resistance indicated that in the range of this study, the optimal level was when the silica and fly ash were substituted by 20%, respectively, as the filler for the sulfur polymer.

• Asian Journal of Turfgrass Science
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• v.18 no.1
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• pp.37-46
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• 2004

The purpose of this study is to find the suitable putting green maintenance equipment for improving the quality of putting green. This study was carried out to investigate the green speed(i.e., ball roll distance) by different the types of greens mower(between work-behind greens mower and riding greens mower), the types of reel blades(between 9 blades and II blades) and the types of roller(between riding soil sprayer and lightweight roller). Green speed of golf course putting greens is assessed by use of Stimpmeter. The west course of Lakeside Country Club was selected for the case study. The results are summarized as follows; 1. The green speed was faster in 3.8 mm moving height treatment plot using work-behind greens mower than in 3.8 mm moving height treatment plot using riding greens mower right after the moving and even after eight hours had passed, and it was statistically significant at a 95% confidence level. Therefore, work-behind greens mower was judged to be a proper equipment type for the fast green management practice than riding greens mower. 2. The green speed was faster in 3.2 mm mowing height treatment plot using work-behind greens mower equipped with II blades than in 3.2 mm mowing height treatment plot using work-behind greens mower equipped with 9 blades, and this result was statistically significant at a 95% confidence level. Therefore, II-blade was judged to be a proper blade type for the fast green management practice than 9-blade. 3. The difference in green speed (green speed increased after rolling) between a treatment plot mowed at 3.0 mm mowing height with the work-behind greens mower and then rolled a single time with riding soil sprayer and a treatment plot mowed at 3.0 mm mowing height with the work-behind greens mower and then rolled once with lightweight roller was not statistically significant at a 95% confidence level. However, the difference in green speed (green speed decreased after rolling) between two treatment plots measured after eight hours had passed was statistically significant at a 95% confidence level. Therefore, the lightweight roller was judged to be a proper roller type for the fast green management practice than the riding soil sprayer.

• Journal of Korean Home Economics Education Association
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• v.22 no.1
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• pp.51-65
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• 2010

The purpose of this study was to raise the awareness of LOHAS(Lifestyle of Health and Sustainability) in the secondary school students. We extracted the related contents to LOHAS from the unit of 'The choice and maintenance of clothing' in the second-year's textbook of Technology-Home Economics, and selected the learning subjects. We also developed the new teaching-learning process plan on practical problem focused lesson, and applied them to the eight classes located in Siheung, Gyeonggi-do, for 5 hours per each class. The learning subjects of the teaching-learning process plan included five items as followings; general awareness, organic fashion, natural fabric, recycled material fashion, and natural dyeing, which were related to LOHAS consumption. The overall topic of the teaching-learning process plan was 'What should do to raise the awareness of LOHAS in order to practice LOHAS consumption in the choice of clothing'. Consequently, the results were abtained as follow; The general awareness of LOHAS as well as the awareness of LOHAS consumption in the choice of clothing increased after classes significantly, compared to those before. Thirty-four materials including worksheets, reading materials and teacher's guide could help to raise the awareness of LOHAS. Also these classes enabled the students to raise their awareness of LOHAS, to improve their opinions and attitudes on LOHAS consumption in the choice of clothing, and to take an interest in the lesson of Home-Economics. This study might have the educational significance in that it made the students directly participate in the national and social trend of the awareness of LOHAS, and upgrade their quality as good LOHAS consumers. Also further teaching-learning process plan in Home-Economics are necessary to promote the awareness of LOHAS for better health, environment, and society.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.4
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• pp.41-54
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• 2020

This study was conducted to provide basic data for a transparent and fair bidding system by identifying problems and suggesting improvement measures through an analysis of the bidding status for construction projects and service-related landscaping of multi-family housing. To this end, we used the data from the "Multi-Family Housing Management Information System (K-apt)" that provides the history of apartment maintenance, bidding information, and the electronic bidding system to examine the winning bid status and amount, along with the size and trends of the winning bids by year, and the results of the selection of operators by construction type. As a result, it was found that out of the total number of successful bids (36,831), 4.4% (16,631) were in the landscaping business, and the average winning bid value was found to be about 24 million won. According to the data, 73% of the landscaping cases were valued between 3 million won and 30 million won, and 58.6% of the cases were in the field of "pest prevention and maintenance". 36% of the total number of bids were awarded from February to April, with "general competitive bidding" accounting for 59.8% of the bidding methods. As for the method of selecting the winning bidder, 55% adopted the "lowest bid" and "electronic bidding method," and 45% adopted the "qualification screening system" and "direct bidding method." As an improvement to the problems derived from the bidding status data, the following are recommended: First, the exception clause to the current 'electronic bidding method' application regulations must be minimized to activate the electronic bidding method so that a fair bidding system can be operated. Second, landscaping management standards for green area environmental quality of multi-family housing must be prepared. Third, the provisions for preparing design books, such as detailed statements and drawings before the bidding announcement, and calculating the basic amount shall be prepared so that fair bidding can be made by specifying the details of the project concretely and objectively must be made. Fourth, for various bidding conditions in the 'business operator selection guidelines', detailed guidelines for each condition, not the selection, need to be prepared to maintain fairness and consistency. These measures are believed to beuseful in the fair selection of landscaping operators for multi-family housing projects and to prepare objective and reasonable standards for the maintenance of landscaping facilities and a green environment.

• Journal of the Korea Institute of Building Construction
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• v.3 no.1
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• pp.93-105
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• 2003

The Precast Concrete(PC) method was developed for a large production of a structure in Europe. Afterwards, this PC method has been applied to a structure and an outside Coating of buildings extensively. The outside Coating of the building applied this PC method is a method to put tiles or stones to base concrete. And there is a method to use paints for, so the expression of various patterns is possible. The Multi-Layer Coating is one of the methods to use paints. This Multi-Layer Coating method can show various designs of external appearance with Foam when it is made with the PC panel. Also, the paint film of the PC panel enables a splendid appearance, and a protective function of concrete is possible, too. Therefore, it makes good durability of the PC. Besides, maintenance is easy to manage because it is free from pollution when it uses metallic materials, stones, or any other materials. You might have no trouble in applying the Multi-Layer Coating method in order to save a merit of an outside Coating on the PC panel. However, the Multi-Layer Coating method used as a current outside Coating method has pollution and bad working environment because Oil Epoxy Resins have toxicity and flammability. Therefore, a lot of warnings are required for coating work in order to have appropriate quality because working hours are short, and production efficiency is low too. These reasons make the cost of construction of the Multi-Layer Coating method increase. And employers or designers may have problems in selecting this Multi-Layer Coating method. Therefore, the purpose of this study is to get activation of the Multi-Layer Coating method by offering improvement measures about the problems of the existing Multi-Layer Coating method.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.17-18
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• 2003

Although flounder is one of the most important marine fish for aquaculture in Korea, feeding the flounder in commercial farms depends mainly on moist pellet in which over 70% frozen fishes (e.g. frozen horse mackerel) are incorporated in its formulation. Therefore, for further expansion of flounder farming, it is essential to employ practical formulated feeds that can support reasonable growth. Development of nutritionally balanced and cost-effective feeds is dependant on the information about nutritional requirement and feed utilization of the species. Nutrient and energy source in feed are needed for the growth and maintenance of fish. Protein is probably the most important nutrient affecting fish growth and feed cost. Therefore, it is essential to determine the optimum dietary protein level for the growth of fish, both its high proportion in the feed and because it is the main factor in determining feed cost. Dietary energy level is also critical because protein source in the feed is utilized as an energy source when the feed deficient in energy is fed to fish, whereas when the feed excess in energy is fed to fish, feed consumption decreased and resulted in growth reduction due to lack of other necessary nutrients for normal growth. Improper dietary protein, energy levels and/or their ratio will lead to an increase of fish production cost and deterioration of water quality resulting from wasted feed; thus, they are important in formulating commercial feed. Dietary lipids play important roles in providing energy and essential fatty acid for normal growth and survival of fish. Although carbohydrates are not essential nutrients for carnivorous fish, these compounds play important roles as a low-cost energy source for protein sparing and also as a feed binder. Nutrition researches for flounder have identified its requirements of protein, lipid and essential fatty acid, vitamin, and minerals for normal growth. Other studies have also been carried out to investigate the utilization of the protein, lipid and carbohydrate sources. Based on these nutritional information obtained, practical feed formulations have been studied for improve aquaculture production of flounder. The results of the researches on utilization of dietary protein, lipid and carbohydrate by flounder are discussed in this review.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.291-296
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• 2006

The purpose of this study were to make clear the present condition of indoor thermal and air environment by air-conditioning in school classrooms and to analyze the relation of the living conditions with indoor environment. The measurements on physical elements and observations on living conditions were carried out in 6 classrooms of 3 middle or high schools. Measuring elements were indoor temperature, relative humidity, $PM_{10}$ and $CO_2$ concentration. As results, the averages of indoor temperature each classrooms were 24.9${\sim}$26.6 . Most of classrooms were lower than the Maintenance standard(26${\sim}$28 ) of School Health Law. The means of relative humidity were 51.3${\sim}$72%, all classrooms were ranged within the standard(30${\sim}$80%). The means of $PM_{10}$ concentration were 3.5${\sim}$23.1 ${\mu}g/m^3$, all classrooms were kept within the standard(100 ${\mu}g/m^3$). The means of $CO_2$ concentration were 1218.7${\sim}$4705.4 ppm, all classrooms were exceed the standard(1,000ppm). The results of analysis on relations of living conditions with the physical elements are as follow; the air conditioner set of temperature, windows and doors opening elapsed time, the number of students in classrooms and activities of students had certain effect on indoor environment.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.4
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• pp.405-420
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• 2008

Resistivity survey is one of the widely used methods for the investigation of stability of the ground or bedrock around tunnel and is also used as an essential base data for stability and reduction of construction cost through first-hand approximation of rock quality at design step. Generally, the analysis of resistivity survey data is performed by single measurement. When distribution variation of groundwater around a tunnel over time is necessary for maintenance of a tunnel, resistivity monitoring is very useful survey method to grasp distribution variation of groundwater. So we performed the grid line resistivity survey to monitoring resistivity variation for six times. And we also tried to evaluate application possibility of the resistivity monitoring for construction safety through providing detailed information on fault zones.