• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1590-1594
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• 2007

This paper describes a case study on dynamic characteristics analysis of a 5-axis multi-tasking machine tool of ram-head typed. Natural frequency and corresponding vibration modes of the machine tool structure were obtained by using both FEM modal analysis and an experimental modal test(impulse hammer test). Both the theoretical and experiment analysis results showed good agreement with each other. Finally, some discussion and review, from the view point of resonance vibration and/or mode coupled chatter, were made based on the analysis results.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.1053-1062
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• 1993

The effect of loading speed on soil failure was studied by using a high speed triaxial compression test. Tests were conducted at 0.35-6.2m/s loading speed to compress soil specimens of sandy loam at different moisture contents. The axial stress at fracture increased with increase in loading speed up to certain critical speeds, however they decreased as the speed up to certain critical speeds, however they decreased as the speed increased further. Experiments were also conducted in the field of sandy loam soil with the vibrating tillage tool. Tests were done at 0.33-0.85m/s tractor speed oscillating frequency 13.7hz and oscillating amplitude 59mm. The maximum oscillating velocity of tillage tool was 2.5m/s. It was observed that for the oscillating operation, initially draft slightly increased with increase in forward speed and then it decreased .For the non-oscillating operation, draft increased continuously with increase in forward speed. Approach of studying soil failure in the laboratory test can be related to the field experiments.

• 한국주조공학회지
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• 제17권2호
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• pp.135-144
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• 1997

The relative machinability of the invar-type cast alloys, such as invar cast steel, invar-type cast iron, Meehanite cast iron, and the modified Invar-type cast iron containing Mo and V was evaluated based on the tool life test, the surface roughness test and the chipping test. Tool life and surface roughness were measured under various cutting conditions. The tool lives of Invar cast steel, Meehanite cast iron, the modified Invar cast iron and Invar cast iron was 12 min, 8 min, 1 min, 41 min, respectively. The surface finish of Invar cast steel and the modified Invar cast iron was better than that of Meehanite cast non, and the chip breakability of invar cast iron and Meehanite cast iron was better than that of invar cast steel. The Taylor's equations of invar cast steel and the modified invar cast iron were $VT^{0.3076}=154.479$ and $VT^{0.3880}=102.326$, respectively. As the cutting speed increases, the surface finish of the modified invar cast iron was improved.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.980-984
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• 2002

This paper has studied thermal characteristics of machine tool to develope high speed spindle and optimum design condidering the thermal deformation. Comparing the test data of temperature measurement and structural analysis data using FEM, we verified the test validity and predicted thermal deformation, influence of spindle generation of heat, and established cooling system to prevent the thermal deformation. 1) The temperature rise of spindle system depends on increasing number of rotation and shows sudden doubling increment of number of rotation over 7,000rpm. 2) Oil jacket cooling can be effective cooling method below 8,000rpm but, over 8,000rpm, it shows the decrement of cooling effect. 3) Comparing FEM analysis results and revolution test results, we can confirm approximate temperature change consequently, it is possible to simulate temperature rise and thermal distribution on the inside of spindle system. 4) We can confirm that simulated approach by FEM analysis can be effective method in thermal-appropriate design.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.820-823
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• 2005

RFID technology offers the possibility that tools and valuable supplies tagged with RFID devices could be tacked down automatically. Such automated tool tracking has the potential to reduce theft, identify underutilized tools to be relocated, insure that crafts have access to the appropriate tools as needed, and reduce overhead labor cost of managing tools. Although other industries have been busy to enhance their supply chain management using RFID technology, construction professionals may be wondering whether it works reliably in construction jobsites as well. This paper presents a field test conducted to determine the reliability of RFID technology in identifying tools in the field storage box. The test indicated that RFID technology is reliable in inventorying tools in field storage.

• 한국보건간호학회지
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• 제28권1호
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• pp.57-70
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• 2014

Purpose: This study is a methodological research study for development of a tool for measurement of care satisfaction of home health nursing in patients who have received care through home health nursing and to test the validity and reliability of the tool. Method: Based on Watson's theory of caring and its constituent factors, the literature related to home health nursing was reviewed, and the standard of home health nursing was compared and analyzed. For verification of the validation and reliability of the final tool which has been developed, data were collected from 166 people who were receiving home health nursing care. Result: According to results of analysis of the factors based on Kaiser and scree test, 10 factors with an eigenvalue greater than 1.0 were extracted, and they explained 72.26% of the total variance. In addition, the factor loadings of 56 questions were greater than .30. For verification of reliability, Cronbach's alpha for all 56 items was .98 and Guttman split half reliability coefficient was .90. Conclusion: This tool based on Watson's theory of caring contributed to development and application of the nursing theory through verification of the theory.

• International Journal of Internet, Broadcasting and Communication
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• 제9권1호
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• pp.56-63
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• 2017

Programming is very important subject in computer science and similar computer-related areas such as electronics engineering, etc. Programming is also important for information education for elementary, middle, and high school students since programming is one of the most basic subjects in computer science courses and other similar areas. In current information and knowledge society, raising programming ability is a key factor for everyone's competitiveness. With highly-competitive programming ability, one can enjoy his or her daily life abundantly. He or she also can get a highly-paid job, and make money using his or her programming ability. In this paper, a programming ability assessment tool is developed and introduced for the no-programming experienced. It is very difficult to test programming ability for the no-programming experienced with non-programming tools or activities. In this paper, a programming ability assessment tool is developed based on logical thinking ability. Especially the proposed tool consists of 15 questions for test one's logical thinking ability. The tool does not require any computer science or programming background. The proposed tool will be helpful as criteria for entrance examination or job screening examination for programming-related areas or subjects.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.375-381
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• 2004

Recently, the evolution in production techniques (e.g. high-speed milling) and the complex shapes involved in modem production design has been increasingly popular. The key to the achievement is a drastic improvement of the dynamic behavior of the machine tool axes used in production machinery. The more complex these tool paths the higher the speed and acceleration requirements. But it is very difficult to reach the target for high speed machine tool because of the limitations of servo system and motion control system. However the direct drive design of machine tool axes, which is based on linear motors and which recently appeared on the market, is a viable candidate to meet the ever increasing demands, because of these advantages such as no backlash, less friction, more mechanical simplicity and very higher acceleration and velocity comparing to the traditional system. This paper focused on the performance tests of the high speed horizontal machine tool based on linear motor. Especially, dynamic characteristics were investigated through circular test and circular form machining test is carried out considering many important parameter. Therefore these several experiments is used to be evaluated the model for prediction of circular motion error and circular machined error.

• 한국컴퓨터정보학회논문지
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• 제22권9호
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• pp.187-192
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• 2017

In this paper, we have studied scale tools for measure programming task value and learning persistence at elementary school students. In order to develop complete test tools, we have improved the completeness by revising tests through stepwise verification. The first scales were constructed based on the previous studies. As a result of the content validity test, 5 out of 14 items of the task value test tool and 1 out of 10 items of the learning persistence test were not suitable. The second test tools were constructed by revising and supplementing the first scale, and consisted of 13 items of task value and 8 items of learning persistence. As a result of the contents validity test, all the items included in the test tool proved to be valid. The reliability of the secondary testing tools were also found to be reliable at ${\alpha}=.970$ and ${\alpha}=.975$, respectively.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1557-1565
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• 2009

According to the GM/RT2141, to assess the safety of vehicle, the validated the vehicle dynamic model should be applied. The validation of the vehicle model is against the static test, some kind of vehicle type test results have been used to determine the suspension characteristics and the vehicle dynamic characteristics. To validate the vehicle model and the test results, first the test results has been analysed as to specified the suspension characteristics and than the parameters to related with the test result has to be adjusted to show the same results of the test. In this process the parameters of vehicle model have been determined to show the coherence of the two results of the simulation and the test by trial & error. In this report, the optimization tool has been introduced in this model validation process and shows the efficient and well validated model.