• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.399-407
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• 2001

The Surface, generated by end milling operation, is deteriorated by tool runout, vibration, friction, tool deflection, etc. Especially in cornering cut, surface accuracy is usually determined by varying cutting forces, which causes tool deflections. Cutting conditions like feed rate is usually kept constant during machining a part, which causes dimensional error in severe cutting. Cornering cut is a typical example of deterioration of surface accuracy when constant feed rate is applied. Therefore it becomes important to develop NC post processor module to determine optimal cutting conditions in various cutting situations. In this paper, cutting force is predicted in cornering cut with flat end mill and feed rate is determined by constraining constantly resultant force. Also some control characteristics of CNC machining center are evaluated.

• Journal of Information Technology Services
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• v.19 no.4
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• pp.13-30
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• 2020

Not only does it cause damage to individuals and businesses due to the occurrence of large-scale personal information leakage accidents, but it also causes many problems socially. Companies are embodying efforts to deal with the threat of personal information leakage. However, it is difficult to obtain detailed information related to personal information leakage accidents, so there are limitations to research activities related to leakage accidents. This study collects information on personal information leakage incidents reported through the media for 15 years from 2005 to 2019, and analyzes how the personal information leakage incidents occurring to companies are related to the characteristics of the company. Through the research results, it is possible to grasp the general characteristics of personal information leakage accidents, and it may be helpful in decision making for prevention and response to personal information leakage accidents.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2173-2174
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• 2011

At the moment, the section insulators for different phases used for over head contact wire system has been all imported since its first application. However, because the section insulators need frequent maintenance and replacement due to the wear by the friction with pantograph and the contamination, which causes its life shorter than as expected, it is required to develop the insulation material with better wear-resistance characteristics and contamination-resistance characteristics. In this thesis, the author developed the section insulator which adopts Teflon tube insulation material which is composed of the Teflon material with the excellent electrical characteristics and wear-resistance characteristics for a longer expected life than that made of conventional FRP.

• Journal of KSNVE
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• v.8 no.1
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• pp.87-98
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• 1998

A Precise actuator in the pick-up of a DVDR/P(Digital Video Disk Recorder/Player) is required to control position accurately. Therefore, in order to develop a reliable actuator, dynamic characteristics of each part in an actuator should be examined closely. This paper presents systematic design process of an actuator using various analysis methods to confirm fundamental capability and solve performance problems related to dynamic characteristics of an actuator beforehand. Particularly, sensitivity analysis is presented through the program using mass moment of inertia and general equations of rigid body. Through the result of sensitivity analysis, important inferiority causes of actuator are selected and reduced. In the end, dynamic characteristics of manufactured actuators are improved considerably.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.539-544
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• 1997

Although the identification of a moving noise source is important in reducing the source power of the transport systems such as airplane or high speed train, the direct measurement of the frequency characteristics is usually difficult due to wind noise when using a microphone running with that noise source. On the other hand the motion of a source causes the frequency characteristics of the pass-by sound measured at a fixed point to be distorted that it is quite difficult to identify the original source characteristics. In this study the relationship between the spectra of the source and the pass-by sound signal is analyzed for a source moving at a constant velocity. The effects of the speed and the frequency characteristics of the source on the pass-by noise spectrum are investigated through numerical simulations.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2495-2497
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• 2000

Level control in the steam generator of a nuclear power plant is important process. But, the low power operation of nuclear power plant causes nonlinear characteristics and non minimum phase characteristics (swell and shrink), change of delay. So, we can't lead good results with conventional PID controller. Particularly, the design of controller with constraints is necessary. This paper introduces MPC(Model Predictive Control) with constraints and designs a good performance MPC controller in spite of the input constraints and nonlinear characteristics, non-minimum phase characteristics

• Korean Journal of Construction Engineering and Management
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• v.23 no.5
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• pp.3-14
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• 2022

Construction projects have high potentials of claims among a variety of stakeholders. Claims on their own are not disputes but they have high potentials leading to disputes if agreements are not made between parties due to conflicting opinions. In the event of the construction disputes between clients and contractors, it could give negative impacts to both parties and, to minimize or pro-actively manage construction disputes, the role of clients is more significant. The objective of the study is to analyze a level of associations between the types of disputes and causes of construction projects based on the association rule analysis, and to identify and discuss key characteristics and implications from client's perspectives. The study analyzes associations between the types of disputes and causes, and also identifies those with a high level of associations. It also presents the outcomes of more systematic analysis compared to descriptive statistics just based on frequencies. Through the analysis of the data cases, the study proposes the directions to resolve the causes of disputes from client's perspectives. It can assist to improve understandings of the relationships between the types of disputes and causes and to pro-actively manage the disputes of construction projects.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.5
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• pp.35-40
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• 2005

An experimental Investigation of the basic characteristics of a micro-cantilever sensor was performed by inspecting the amplitude and frequency characteristics of a commercial tuning fork (TF). Application of acetone and ethanol with a volume of $1{\mu}l$ on the tine of a vibrating tuning fork causes immediate response in its amplitude and frequency characteristics. It has been shown that the tuning fork has ability to recognize a chemical agent with high sensitivity. The theoretical sensitivity of mass loading is in the range of $\~0.1Hz/ng$. Quartz tuning forks are routinely made using standard microfabrication process, thus suggesting the possibility of microfabrication of micro quart sensors.

• Quality Improvement in Health Care
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• v.29 no.2
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• pp.15-31
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• 2023

Purpose: This study aimed to identify the characteristics of patient safety incidents (PSIs) related to nursing and to provide primary data for preventing the recurrence of similar incidents. Methods: This secondary analysis study included damage claims rulings filed for clinical negligence from 2014 to 2018 that contained the keyword 'nurse'. It excluded judgments irrelevant to nursing care and in which clinical negligence or causal damages were overruled. A total of 93 cases were analyzed. The characteristics of PSIs were derived through descriptive statistics, and two instances of nursing-related PSIs were examined by qualitative content analysis focusing on root causes. Results: The analysis of PSIs related to nursing suggested that the medical institutions where the PSIs occurred most frequently were hospitals, and the most common types of PSIs were medication, surgery, and treatment/procedure, in that order. In addition, it indicated that nursing-related PSIs occurred most frequently in general wards during the day shift, with the most common related nursing practice being managing potential risk factors. The qualitative analysis showed that careless monitoring and institutional inertia were causes of PSIs. Conclusion: To prevent nursing-related PSIs, nurses need to individually monitor and assess patient conditions. In addition, support should be accompanied by the improvement in the systems in place aimed at preventing the recurrence of nursing-related PSIs at the institutional and national level, such as securing appropriate nursing personnel and improving labor conditions.

• Journal of Korean Home Economics Education Association
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• v.24 no.2
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• pp.1-15
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• 2012

This study investigated the causes of the dislikes of Practical Arts education of elementary school students. This study was to provide the foundation for the proposition of alternative plans to make more students participate pleasantly and actively in Practical Arts classes. Data were collected via an open-ended survey from 273 elementary school students and through telephone interviews with five elementary school teachers. The data were analyzed inductively by NVivo. After the analysis of the student data, the analysis of the teacher data was conducted according to the variables from the student data. The results of this research were as follows: First, with regard to the causes of the students' dislikes of Practical Arts classes, extrinsic factors such as instruction management, instruction content, teaching facilities and equipment, and teacher characteristics were elicited. Intrinsic factors included complaints about failing to meet students' expectation from Practical Arts, negative perception of Practical Arts, the interest, competency, and fear of the students. Secondly, the students who learned Practical Arts from the Practical Arts specialty teachers gave more answers on instruction management, instruction content, and teacher characteristics than the students who learned Practical Arts from their homeroom teachers did. The students who learned Practical Arts from their homeroom teachers answered that they disliked Practical Arts because of lack of lab facilities and practice than their counterparts did. The analyses of teacher data provided the reasons and contexts of the dislikes of the students such as teaching facilities and equipment, and the anxiety of the students.