• Transactions on Control, Automation and Systems Engineering
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• 제1권2호
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• pp.94-98
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• 1999

Optical scanning systems use glavanometers to point the laser beam to the desired position on the workpiece. The angular speed of a galvanometer is typically controlled using Proportional+Integral+Derivative(PID) control algorithms. However, natural variations in the dynamics of different galvanometers due to manufacturing, aging, and environmental factors(i.e., process uncertainty) impose a hard limit on the bandwidth of the galvanometer control system. In general, the control bandwidth translates directly into efficiency of the system response. Since the optical scanning system must have rapid response, the higher control bandwidth is required. Auto-tuning PID algorithms have been accepted in this area since they could overcome some of the problems related to process uncertainty. However, when the galvanometer is attached to a larger mechanical system, the combined dynamics often exhibit resonances. It is well understood that PId algorithms may not have the capacity to increase the control bandwidth in the face of such resonances. This paper compares the achieable performance and robustness of a galvanometer control system using a PID controller tuned by the Ziegler-Nichols method and a controller designed by the Quantitative Feedback Theory(QFT) method. The results clearly indicate that-in contrast to PID designs-QFT can deliver a single, fixed controller which will supply high bandwidth design even when the dynamics is uncertain and includes mechanical resonances.

• 제어로봇시스템학회논문지
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• 제12권2호
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• pp.119-129
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• 2006

Art psychotherapy is widely accepted as an effective tool for diagnosis and treatment of psychological disorders. Important factors for art psychotherapy diagnosis, based on the projection theory that the world of the inner mind appears in drawings, include main color and imbalance of a drawing. This paper develops a system for a machine to determine the main color and the imbalance of a drawing by color recognition and edge detection. Our proposed color recognition procedure adopts NBS(National Bureau of Standards) distance between colors in HVC(Hue, Value, Chroma) color space which is most similar to the human eye's color perception. Our edge detection procedure applies blurring, clustering and transformation to a standard color in a series. Our system considers the numbers of pixels and clusters for each color as a criterion for main color and the frequency of edge coordinates for each region for imbalance. The proposed machine procedure, verified through case studies, can help overcome the subjectivity, ambiguity and uncertainty in human decision involved in art psychotherapy.

• 대한간호학회지
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• 제31권6호
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• pp.1021-1033
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• 2001

This study sought to find a nursing intervention tool for enhancing elderly women's lives by investigating the causes and the meaning of their grief. Method: This research was derived from a phenomenological tool such as qualitative research design. The data collection took place from December of 2000 until April of 2001 Through systematic interviews and participatory observations of five elderly women attending C welfare center located in downtown Seoul the data was collected. Each interview lasted an hour and a half and was arranged five times. The analysis of this research was conducted using the Giorgi method. Results: \circled1 There was obvious physical and physiological decline caused by aging old; as well as there being spouse health problems, additional physical suffering, signs of senility, and insomnia, \circled2 Further grief was imposed by unpleasant memories of the spouse; infidelity, incapability, and even disregard of her own well-being, \circled3 Then there was pity for children; unfaithful children, uncertain futures of the children, and early death of a child, \circled4 Also, regrettable fate, painful daily acttrities, unreliable factors, bad circumstances, and feelings emptiness were reported, \circled5 Finally, anxiety for the future; ac sense of despair, loneliness, economic hardship, and the fear of imminent death increased grief levels. Conclusion: A variety of programs and social meetings for the elderly to overcome their physiological or psychological crisis should be substantially developed and supported by the government. In order to implement the social welfare for the elderly women, special consideration whether on the governmental level or the personal level, should be devoted to the elderly who live without any financial support or social concern.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제38권4호
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• pp.195-203
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• 2012

Dental implants using titanium have greatly advanced through the improvement of designs and surface treatments. Nonetheless, the anatomical limits and physiological changes of the patient are still regarded as obstacles in increasing the success rate of implants further, even with the enhancement of implant products. So there have been many efforts to overcome these limits. The intrinsic potential for bone regeneration can be stimulated through adjuvant treatments with the continuous improvement of implant properties, and this can play an important role in achieving optimum osseointegration toward peripheral bone tissue and securing ultimate long-term implant stability in standard surgical procedures. For this purpose, various chemical, biological, or biophysical measures were developed such as bone grafts, materials, pharmacological agents, growth factors, and bone formation proteins. The biophysical stimulation of bone union includes non-invasive and safe methods. In the beginning, it was developed as a method to enhance the healing of fractures, but later evolved into Pulsed Electromagnetic Field, Low-Intensity Pulsed Ultrasound, and Low-Level Laser Therapy. Their beneficial effects were confirmed in many studies. This study sought to examine bone-implant union and its latest trend as well as the biophysical stimulation method to enhance the union. In particular, this study suggested the enhancement of the function of cells and tissues under a disadvantageous bone metabolism environment through such adjunctive stimulation. This study is expected to serve as a treatment guideline for implant-bone union under unfavorable circumstances caused by systemic diseases hampering bone metabolism or the host environment.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8067-8073
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• 2016

Background: Long non-coding RNAs (lncRNAs) are emerging as key players in gene expression that govern cell developmental processes, and thus contributing to diseases, especially cancers. Many studies have suggested that aberrant expression of lncRNAs is responsible for drug resistance, a substantial obstacle for cancer therapy. Drug resistance not only results from individual variations in patients, but also from genetic and epigenetic differences in tumors. It is reported that drug resistance is tightly modulated by lncRNAs which change the stability and translation of mRNAs encoding factors involved in cell survival, proliferation, and drug metabolism. In this review, we summarize recent advances in research on lncRNAs associated with drug resistance and underlying molecular or cellular mechanisms, which may contribute helpful approaches for the development of new therapeutic strategies to overcome treatment failure.

• 한국정밀공학회지
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• 제19권12호
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• pp.70-77
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• 2002

Necessity of the tole-operation has been increased in many fields. Since the Internet is inexpensive and available all over the world, it is a strong candidate for the transmission media of the tole-operation. However, the Internet has random time delays that may cause instability in the system especially if the tole -operation is bilateral. In the past few years many attempts have been made to overcome the random time delay, So far, they are still insufficient in terms of performance. The ‘Variable holding time’ is introduced to improve the performance of the ‘Event based tole-operation’ which controls a system with a non-time action reference. By holding each event for proper time, the system can quickly respond and be stabilized. The proper holding time should be selected based on the characteristics of the task that the system performs. The factors that reflect those characteristics are investigated. The fuzzy logic is employed to obtain the proper holding time for each event while the tole-operation system is in operation. The experimental results presented in this paper verify effectiveness of the proposed method.

• 성인간호학회지
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• 제26권5호
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• pp.592-602
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• 2014

Purpose: This study was to provide understanding about the meaning of nasogastric tube feeding experiences by the cerebral stoke patients with dysphagia. Methods: Data were collected through a face to face interview from five cerebral stroke patients who had dysphagia along with a nasogastric tube insertion. The contents of the interviews were analyzed using the hermeneutics phenomenological method developed by van Manen. Results: The experience of having a nasogastric tube was not only limited to physical problems but also was linked to other psychological problems. Many patients reported that they tolerated the nasogastric tube in order to overcome the stroke along with the desire to eventually take food orally. The essential themes associated with the experience of nasogastric tube insertion were: "The loss of pleasure from food", "The loss of human relationship from surrounding table", "Cower and shrink from the different appearance to others" and "Acceptance for life in painful experiences". Conclusion: This study would highlights the importance of not only physical focused care but also psychological and social aspects. Therefore, nurses should consider all factors when providing nursing care to stroke patient with nasogastric tube feeding.

• 세라미스트
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• 제23권1호
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• pp.16-26
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• 2020

Recently, polymer-metal composite (IPMC)-based ionic artificial muscle has been drawing a huge attention for its excellent soft actuator performance having outstanding soft actuator performance with efficient conversion of electrical energy to mechanical energy under low working voltage. In addition, light, flexible and soft nature of IPMC and high bending strain response enabled development of versatile sensor application in association with soft actuator. In this paper, current issues of IPMC were discussed including standardizing preparation steps, relaxation under DC bias, inhibiting solvent evaporation, and improving poor output force. Solutions for these drawbacks of IPMC have recently been suggested in recent studies. After following explanation of the IPMC working mechanism, we investigate the main factors that affect the operating performance of the IPMC. Then, we reviewed the optimized IPMC actuator fabrication conditions especially for the preparation process, additive selection for a thicker membrane, water content, solvent substitutes, encapsulation, etc. Lastly, we considered the pros and cons of IPMCs for sensor application in a theoretical and experimental point of view. The strategies discussed in this paper to overcome such deficiencies of IPMCs are highly expected to provide a scope for IPMC utilization in soft robotics application.

• Journal of Information Technology Applications and Management
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• 제20권1호
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• pp.19-41
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• 2013

This study analyzed the users acceptance of e-Government services. Many IT(Information Technology) adoption studies appeared the TAM(technology adoption model) of Davis[1989] as a theoretical background. The TAM composed of three factors those are the perceived easy of use, the perceived usefulness, and intention to adoption of IT. However, TAM did not explain the consequences of intention to adoption and antecedents of the ease of use and usefulness in IT adoption. To overcome limitations of TAM, many technology acceptance studies done. In this study, the researcher suggested the IT acceptance model for explaining users adoption of e-Government service based on the model of IT acceptance of Wixom and Todd[2005]. The model of Wixom and Todd[2005] based on the TAM of Davis[1989], IT adoption model of Taylor and Todd[1995] and, IS(Information Systems) success model of Delone and Mclean[1992, 2003]. For testing our research model, the researcher collected data from 200 users of e-Government services. The researcher analyzed in measurement model and structural model using statistical software. This study analyzed relationships among interaction, information quality, Web systems quality, satisfaction, ease of use, usefulness, and attitude to explain and predict influences of the users acceptance of e-Government services. The results of this study will provide useful information about develop a strategy for usage spread of e-Government services.

• 한국군사과학기술학회지
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• 제12권3호
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• pp.259-265
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• 2009

In the traditional percussion locks of small arms, a firing pin is struck by a hammer rotating on a single center of rotation, which makes the percussion mechanism simple and reliable. In order to strike the firing pin by the hammer, however, the firing pin should be located within the radius of rotation of the hammer. As the distance between the striking point of the firing pin and the center of rotation of the hammer becomes longer, the radius of rotation of the hammer should also be increased, which results in the increase of the volume and weight of the small arms because the hammer needs the more space for its operation inside of the small arms. In this paper, a link type percussion lock was newly proposed in order to overcome the limitation of designing small arms when using traditional percussion locks, as mentioned above. The link type percussion lock was modeled by using multi-body dynamics software and designed to satisfy the requirements such as striking force level of the hammer exerting on the firing pin enough to detonate the percussion cap of ammunitions and the safety on the accidental drop. It was applied to the newly developed dual-barrel weapon system, in which the weight and overall length are important design factors, and verified by durability test and drop test on the ground.