• Korean Journal of Agricultural Science
• /
• v.22 no.1
• /
• pp.11-23
• /
• 1995

The CAD/CAM system for the manufacturing automation is the newest technology in mechanical engineering area and becomes the important research subject nowadays. Most of all hardwares and softwares for the CAD/CAM system used in the our manufacturing companies such as automobile company are developed by the foreign country and the purchasing price of them is very expensive but their applicability to a certain area is very limited. This study was conducted to develope a CAD/CAM system for the design and the automatic manufacturing of the iron pattern shaped with 3 - dimensional free curved surface, and to test its applicability to the design and the manufacturing of the rotary blade. The results obtained from the study are as follow; 1. The CAD system which can process graphic procedures from the free curved surface shaped data was developed with personal computer. 2. The CAM main program was developed. This main program could produce CL data from CAD data file by checking the tool interference according to the cutting mode. 3. The sub. program which can simulate the tool trace from the CL data was developed. 4. The post processor for the Deckel FP2NC NC milling machine from CL data file was developed and the sub program could transmit NC program through modem to NC milling machine was developed. 5. The developed CAM system seemed to be applicable to any other system. Because the measuring results of the cross sectional thickness of the plastic model from the manufacturing iron pattern by the system showed that this system could properly check the tool interference. 6. In took 75~90 hours to manufacture two iron patterns of rotary blade. For the sake of convenience in applying to the other systems, this system was developed in BASIC and FORTRAN computer language and minimum portion of machine language as possible.

• Smart Structures and Systems
• /
• v.17 no.1
• /
• pp.73-89
• /
• 2016

The stress dependence of ultrasonic wave velocity is known as the acoustoelastic effect. This effect is useful for stress monitoring if the acoustoelastic coefficient of a subject medium is known. The acoustoelastic coefficients of metallic materials such as steel have been studied widely. However, the acoustoelastic coefficient of concrete has not been well understood yet. Basic constituents of concrete are water, cement, and aggregates. The mix proportion of those constituents greatly affects many mechanical and physical properties of concrete and so does the acoustoelastic coefficient of concrete. In this study, influence of the water-cement ratio (w/c ratio) and the fine-coarse aggregates ratio (fa/ta ratio) on the acoustoelastic coefficient of concrete was investigated. The w/c and the fa/ta ratios are important parameters in mix design and affect wave behaviors in concrete. Load-controlled uni-axial compression tests were performed on concrete specimens. Ultrasonic wave measurements were also performed during the compression tests. The stretching coda wave interferometry method was used to obtain the relative velocity change of ultrasonic waves with respect to the stress level of the specimens. From the experimental results, it was found that the w/c ratio greatly affects the acoustoelastic coefficient while the fa/ta ratio does not. The acoustoelastic coefficient increased from $0.003073MPa^{-1}$ to $0.005553MPa^{-1}$ when the w/c ratio was increased from 0.4 to 0.5. On the other hand, the acoustoelastic coefficient changed in small from $0.003606MPa^{-1}$ to $0.003801MPa^{-1}$ when the fa/ta ratio was increased from 0.3 to 0.5. Finally, it was also found that the relative velocity change has a linear relationship with the stress level of concrete.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.13 no.6
• /
• pp.105-112
• /
• 2005

This study aims at evaluating the environmental impacts stemmed from the End-of-Life Vehicle(ELV) treatment systems in Korea, using Life Cycle Assessment(LCA) method. In this study, both environmental burden from the ELV dismantling process & recycling processes and environmental benefit which were derived from the avoided environmental impacts by substituting recycled materials for virgin materials were considered. First of all, the key issues which were defined as the environmental aspects that account for more than $1\%$ out of the total environmental impacts were identified from the Life Cycle Impact Assessment(LCIA). $CO_2$, crude oil, natural gas, coal, etc. were found out to be the key issue parameters. From the LCI Analysis and LCIA studies, it was shown that the significant environmental aspects were related with the recycling process of ferro scrap, the shredding process of compressed car bodies and the dismantling process of end-of-life engines. In particular, the recycling process of ferro scrap has the most significant effects on the environmental impacts of the ELV treatment systems. Based on these results, it is recommended to improve the recycling process of ferro scrap in order to make the ELV treatment systems more environmentally sound.

• KSBB Journal
• /
• v.30 no.1
• /
• pp.11-20
• /
• 2015

Radiation causes various pathophysiological alterations in living animals, and it causes death at high doses by multiple mechanisms, including direct DNA damage and indirect oxidative stress. The search for useful radioprotectors has been an important issue in the field of radiation biology. Ideal radioprotectors should have low toxicity and an extended window of protection. As many synthetic compounds have toxic side effects, the natural products have attracted scientific attention as radioprotectors. Natural products that have been recently shown to be effective with various biological activities were found to have radioprotective effect. The aim of this review is to summary the recent research of the radioprotective effects of natural foods, especially focused on the glycobiological properties of mushrooms.

• Korean Journal of Construction Engineering and Management
• /
• v.7 no.4 s.32
• /
• pp.154-163
• /
• 2006

Recently, the demand for performance evaluation and management at the industrial or corporate level has been increasing. From this perspective, this study has developed indicators to measure and compare construction company performances and we have analyzed various characteristics of those indicators. Throughout our thorough qualitative and quantitative analysis we first identified a set of indicators for performance measurement. These indicators have been shown to meet the requirements of validity, measurability, and comparability. Second, we calculated the performance index of construction companies by applying weightings of the performance categories. Then we performed correlation and regression analyses using the calculated performance index and identified the basic cause-and-effect relationships, as well as the statistical characteristics of the performance index. Drawing on the results of the analytical processes identified in this work, we discuss future research to be conducted.

• Journal of the Korean Society of Safety
• /
• v.26 no.1
• /
• pp.49-57
• /
• 2011

A questionnaire study was carried out to understand the status of performing the risk assessment of work-related musculoskeletal disorders(WMDSs), which is the employers' legal responsibility when the employees are involved in doing tasks with risk factors. Employers or managers from 340 companies and the representative employees from 250 companies participated in the survey. According to the participated employers and employees, 35.0~46.2% of companies had performed the first risk assessment before the end of 2005. However, it is presumed that the real condition might not be as much as the result, because most companies were very reluctant to took part in the survey. It was found that the type of business and size of the company are the main factors affecting the performance of the risk assessment in terms of the performing ratio, method, and so on. The participants were positive in the thought that the assessment would be helpful in preventing msuculoskeletal disorders, while there was a little difference between the employers and employees in the thought that the assessment would be helpful in finding the injuries in the early stage. It was found that it is necessary to modify and improve the definition and criteria of the tasks to be examined in the assessment.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.29 no.2
• /
• pp.286-297
• /
• 2005

Recently, due to the gloalization of the industry environment and the consequent multi-national companies led by industrialized countries, fashion companies of newly industrialized countries are pursuing to globalize their businesses. This study conducted to review the global configuration of activities of the added value chain, the strategies to enhance global competitiveness, and global performance of value activities of Korean fashion companies. The data were collected from the survey by questionnaire on Korean fashion companies. The methods of analysis used in this study were regression, and descriptive statistics of the data. the results werw as follows. First, Korean fashion companies were undergoing diverse value activities through their foreign subsidiaries and overseas out-sourced companies in a wide spectrum of business activities ranging from design/planning o products to marketing/logistics. Second, the global competitive strategies that the Korean fashion companies were most focused on were the cost/productivity aspects. The efforts to differentiate the products from competitors, the efforts for innovation, an the efforts of growth were the next strategies. The strategy that was least emphasized was on seeking alliance with other business partners. Third, the result of the globalization efforts showed an overseas market growth of and average of 9%, and an average overseas market profit of 7.8%. The overall satisfaction on the result of the overseas market activities, and the rate of accomplishment of market targets were generally low.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2012.05a
• /
• pp.20-25
• /
• 2012

New Zealand suffers from regular floods, these being the most common source of insurance claims for damage from natural hazard events in the country. This paper describes the origin and distribution of the largest floods in New Zealand, and describes the systems used to monitor and predict floods. In New Zealand, broad-scale heavy rainfall (and flooding), is the result of warm moist air flowing out from the tropics into the mid-latitudes. There is no monsoon in New Zealand. The terrain has a substantial influence on the distribution of rainfall, with the largest annual totals occurring near the South Island's Southern Alps, the highest mountains in the country. The orographic effect here is extreme, with 3km of elevation gained over a 20km distance from the coast. Across New Zealand, short duration high intensity rainfall from thunderstorms also causes flooding in urban areas and small catchments. Forecasts of severe weather are provided by the New Zealand MetService, a Government owned company. MetService uses global weather models and a number of limited-area weather models to provide warnings and data streams of predicted rainfall to local Councils. Flood monitoring, prediction and warning are carried out by 16 local Councils. All Councils collect their own rainfall and river flow data, and a variety of prediction methods are utilized. These range from experienced staff making intuitive decisions based on previous effects of heavy rain, to hydrological models linked to outputs from MetService weather prediction models. No operational hydrological models are linked to weather radar in New Zealand. Councils provide warnings to Civil Defence Emergency Management, and also directly to farmers and other occupiers of flood prone areas. Warnings are distributed by email, text message and automated voice systems. A nation-wide hydrological model is also operated by NIWA, a Government-owned research institute. It is linked to a single high resolution weather model which runs on a super computer. The NIWA model does not provide public forecasts. The rivers with the greatest flood flows are shown, and these are ranked in terms of peak specific discharge. It can be seen that of the largest floods occur on the West Coast of the South Island, and the greatest flows per unit area are also found in this location.

• Fire Science and Engineering
• /
• v.25 no.2
• /
• pp.33-38
• /
• 2011

This study is a research for analysis the states of flame resistant treatment and its system which important in fire prevention by ignition delay of early stage of fire. Some problems arose in the flame resistant treatment site were analysed through the meeting with fire officer and businessman related with flame resistant treatment, and visiting the flame resistant treatment places. From the meeting, visiting and reviewing the code system we find the following problems. First one is a problem of excessive competition with many company in small market of flame resistant treatment and to reduce the cost, the businessman who have no professional technic do not work along the specification. Second one is the inspection system which do not inspect on site but inspect by sampling the flame resistant treated materials submitted by businessman. And there are some problems arose about the reliability and consistency of flame resistant performance of the sample and the treated site. To solve the above problems, we suggest some countermeasure.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.5
• /
• pp.3146-3152
• /
• 2014

This paper investigates the determinants for the controlling power and the concentration of the subcontracting trade between the downstream producer and the upstream supplier using a survey data for the IT industry in Gyeonggi-Do. The estimation results of the ordered logit and least square analyses are as follows. First, a firm. s controlling power across the downstream producer and the upstream supplier in the subcontracting trade would grow bigger when the company is bigger, more manufacture-oriented, and has higher ratio of export in sales. Second, the analysis for the upstream suppliers indicates that the higher dependent ratio of the subcontracting trade in the sales, the lower the concentration ratio of the R&D in the sales. Lastly, the analysis of the downstream producers indicates that the higher the dependent ratio of the subcontracting trade in the sales, the higher the concentration ratio of the R&D in the sales, which is distinctively contrast with the analysis result of the upstream suppliers. The overall estimation results are, hence, unsupporting to the transaction cost theory which predicts the increase of R&D investments in both downstream producer and upstream supplier.