• Proceedings of the KSR Conference
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• 2007.05a
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• pp.468-476
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• 2007

Generally, the strength of the field shotcrete is heavily dependent on the field mixing and spraying conditions so that it is different from the strength of the shotcrete mixed in laboratories. As a support member, the early strength of shotcrete unlike concrete as structural material is very important to the initial stabilization of the excavation face in tunnels. Therefore, the field methods to efficiently test the early strength of shotcrete have been highly required. This paper aimed to verify the pneumatic pin penetration test and the point load test for measuring the early strength of the field shotcrete. Through a series of uniaxial compression, pin penetration, and point load tests for the range of the early shotcrete strength, two equations to estimate reliably the uniaxial compressive strength by the pin penetration and the point load tests were derived. Field tests in working tunnel were carried out in order to estimate the economic efficiency. As a result, pin penetration method was proved to be the most effective method for testing the early strength of the field shotcrete.

• Korean Journal of Occupational Health Nursing
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• v.29 no.1
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• pp.88-96
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• 2020

Purpose: This study aimed to identify the mental fitness, perspective taking, attitude toward the elderly, and quantitative encephalogram among caregivers. Methods: In this mixed method research, 14 female caregivers at an elderly care facility in Y city were participated from December 1st to December 31st, 2019. Structured questionnaires were applied to measure general characteristics, mental fitness, perspective taking, and attitude toward the elderly. Brain waves were measured by quantitative encephalogram in the prefrontal lobe. High frequency and high level of care tasks were analyzed using content analysis. Results: According to analysis of brain waves, caregivers experienced high level of physical strain & stress and psychological distraction & stress. Mental fitness (p<.05) and perspective taking (p<.001) were associated with attitude toward the elderly. Moreover, physical strain & stress was associated with psychological distraction & stress (p<.05, p<.001). High frequency and high level tasks were excretion and position change & movement care related tasks, respectively. Conclusion: These findings should be consider as an evidence for supporting care tasks based on concrete and objective understanding of caregivers using self-reported index as well as neurophysiological indicators including brain waves.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.67-68
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• 2017

This paper discusses the application of civil structure use reinforcing fiber mixed with concrete to be used as protection layer of waterproofing material and root resistant layer installed in below-grade parking lot upper slab of residential building. A performance evaluation under the prescribed method outlined in KS F 4938 was used for this new material. The testing results showed that the fiber reinforcement can be used to strengthen the protection for the waterproofing material. Also, plants that were planted in June 2016 have not yet penetrated the specimens used for root resistance testing. The domestic root resistance performance testing usually covers the period of 2 years, thus further observation to make any conclusion about the root resistance property is required.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.93-97
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• 2008

The study analyzed on each kind of basic characteristics in mortar to prove an effect of pre-mix cement, ultra high strength binder. The results were as follows. in characteristics of not set mortar, fluidity time was the quickest at the time of using POBSA and was more delayed at the time of using Fly Ash than at the time of using Blast Furnace Slag as a binder. Mortar ring flow and flow con flow got smaller as fluidity time got longer, on the contrary to fluidity time. Unit capacity mass was smaller at the time of using Fly Ash than at the time of using Blast Furnace Slag. According to pre-mix, it was difficult to discover a regular tendency. In characteristics of hardening mortar, the 28th day compressive strength was better than thing mixed after measuring separately in pre-mix. According to a binder's kind, Silica Fume B, C was better than Silica Fume A.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.212-218
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• 1996

The concrete pipe used to distribute irrigation water to the right place now available is commonly made up of cement , sand, earth, pebble, etc. These materials with right ratio and right amount of water were mixed and squeezed through the pipe-making machine called vertical squeezed pipe-making machine, and then a cement prefabricated pipe is produced . This kinds of pipe has been expanding by leaps and bounds. Being little cement contents and low cost, the length of pipe is 1.0m or so with weight of 50kg, which is easy to be made and to be transported. The demolish pressure of it is 0.2 MPa or so, which meets the needs of agriculture irrigation . The buried pipe irrigation system, has been popularized in Jining Municipal , Shandong Province. By the year of 1995 , the irrigation area under pipe conveyancesystem usign this type of pipe has reached 74000 hectares. By calculation, about 27.7million ㎥ water, 2.88 million kWh power , 0.167 million man power and 1528 hectares cu tivated land will be saved one year, adding value of agriculture output increased by 10 million kg. The total economic benefits amount to 0.92 million US$ a year. The paper presents the pipe making course and its application on a large scale area.

• International Journal of Highway Engineering
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• v.20 no.1
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• pp.97-105
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• 2018

PURPOSES : Asphalt concrete pavement is damaged by various causes such as traffic and environmental loads. The distressed pavement should be maintained by various methods to provide a comfortable and safe pavement for the driver. This study evaluates the effect of adding a mixing procedure to enhance the mixture quality in the hot in-placement recycled asphalt pavement method, which is an asphalt-pavement maintenance method. METHODS : Various test methods such as Marshall stability and dynamic stability, were employed to estimate the recycled asphalt mixture with and without an additional mixing, using the hot in-placement recycled asphalt pavement method. RESULTS : The mixture samples used in this study were taken before and after the addition of the mixer in the hot in-placement recycled asphalt pavement method (HIR) at field construction sites in GongJu and JinJu in South Korea. The test results of both mixtures satisfied the asphalt-mixture standard specifications. CONCLUSIONS : This study confirmed that adding a mixer in the HIR method results in a well-mixed new asphalt mixture, rejuvenator, and reclaimed asphalt mixture.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.51-53
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• 2012

기업의 목적은 이익을 창출하는 데 있다. 이를 위해서는 제품별 생산성을 높여 원가를 절감해야 하지만, 대부분의 레미콘 제조업체는 원가관리를 운영하지 못하고 있는 실정이다. 레미콘 제조업체의 제품공정은 단순하나 제조원가 중 직접재료비가 약 70% 이상으로 큰 비중을 차지하고 있다. 따라서 원가절감의 여부가 경영성과에 미치는 영향이 크다고 할 수 있다. 또한, 정부 공공기관 등은 예산을 안정적으로 관리하고, 부당한 지출을 방지하기 위하여 엄격하게 원가계산제도를 운영하고 있다. 레미콘 제조업체의 원가관리를 위해서는 우선적으로 업체 특성에 맞는 원가관리 시스템을 구축하여야 한다. 이를 위해서 본 논문에서는 레미콘 제조업체의 특성에 맞는 원가관리 시스템을 설계하였다. 시스템 설계는 전체 프레임워크, 처리 절차, 데이터베이스 스키마와 자료구조, 입력 출력 설계로 구성하였다. 원가계산의 절차는 정부원가계산 제도를 이용하여 설계하였다. 본 논문의 성과로, 계약자는 원가정보를 신뢰하며 이용할 수 있고, 레미콘 제조업체의 원가정보 표준화에 기여할 것으로 기대한다.

• Management & Information Systems Review
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• v.14
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• pp.101-115
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• 2004

As a corporate and a taxation account have relationships each other, one cannot be ignored by the other from concrete and excepted points of view. In reality, as they are mixed and the taxation account has been regarded as absolute, we cannot deny that the role of a pure corporate account is intruded by taxation account. Therefore, it is important that both should be adjusted in order to develop their own roles between a corporate account and a taxation account. In order to develop the both accounts soundly, we should solve the problems as follows. First, we should discriminate closing adjustment affairs from reporting adjustment ones, In the process of adjusting for taxation report. Second, the manager and the accounter need to comprehend on the origin and reality of a corporate and a taxation account and improve their capacity of accounting. Finally, as the goals which both aspects seek for are different, it is difficult to meet each other. But it will be a shortcut for enhancing the capacity of the corporate management, and developing the accounting systems of Korea, to compensate the differences each other. In conclusion, this writer suggest that the corporate accounts should be treated according to the corporate accounting principle, and taxation law has to be reformed so that taxable income may be counted based on the former assertion.

• Geomechanics and Engineering
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• v.9 no.3
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• pp.329-344
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• 2015

Cratering tests in rock are generally carried out to identify its fragmentation characteristics. The test results can be used to estimate the minimum amount of explosives required for the target volume of rock fragmentation. However, it is not easy to perform this type of test due to its high cost and difficulty in securing the test site with the same ground conditions as the site where blasting is to be performed. Consequently, this study investigates the characteristics of rock fragmentation by using the hydrocode in the platform of AUTODYN. The effectiveness of the numerical models adopted are validated against several cratering test results available in the literature, and the effects of rock mass classification and ground formation on crater size are examined. The numerical analysis shows that the dimension of a crater is increased with a decrease in rock quality, and the formation of a crater is highly dependent on a rock of lowest quality in the case of mixed ground. It is expected that the results of the present study can also be applied to the estimation of the level and extent of the damage induced by blasting in concrete structures.

• Journal of the Korean housing association
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• v.15 no.3
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• pp.43-51
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• 2004

The purpose of this study is to examine the physical characteristics of the detached housing area in the housing site development district. The process of this study is to investigate the characteristics of the physical structure and the building use, then to analyze the relationship of physical structure and the building use in the aspect of the morphological characteristics. The case study focuses on the Chil-kok2, An-Siml in Taegu. The streets pattern is composited gird and loop type mixed. The block is composited by 2 lots in general. But the obscurity of organization and character of the streets, the size and shape of lots which is not fit to the building use. A whole residential characters appears high residential density ratio. so residential environment became worse. The improving level of residential environment and efficiency of land use in the detached housing area of the housing site development district, firstly the propriety of the physical structure must be considered about detached house characters, and the housing uses which fit to the physical structure are needed, and also for the concrete realization of this, the designation of district, the zoning of residential area, the guideline of the district design, and establishment of comprehensive master planning in detached housing area are needed in aspect of the housing policy. As the result of this study, it suggests several design guideline to improve housing site development.