• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1176-1180
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• 2008

This paper represents a study on design hypothesis to improve properties of a product. The functional requirements and function structure of various technical products are analysed. From the above analysis we could formulate one hypothesis. This hypothesis also satisfies basic rules clarity, simplicity and safety that are required in all design cases. The hypothesis says that functional requirements is refined to improve and if there are components which have the same function, they can be integrated into one component and improved. A one-handed faucet was developed by applying the above hypothesis to a two-handed faucet. The design of heat exchange tester was be improved successfully through the hypothesis.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.4
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• pp.214-220
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• 2004

This paper describes a busbar current differential relay in conjunction with a current transformer(CT) compensating algorithm irrespective of the level of the remanent flux. The compensating algorithm detects the start of first saturation if the third-difference function of the current exceeds the threshold; it estimates the core flux at the first saturation start by inserting the negative value of the third-difference function of the current into the magnetization curve; thereafter, it calculates the core flux during the fault and compensates the distorted current using the magnetization curve. The algorithm estimates the correct secondary current irrespective of the level of the remanent flux and needs no saturation point of the magnetization curve. The proposed relay can improve not only security of the relay on an external fault with CT saturation but sensitivity of the relay on an internal fault; the relay can improve the operating speed on n internal fault with CT saturation. This paper concludes by implementing the relay into a digital signal processor based prototype relay.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.4
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• pp.214-214
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• 2004

This paper describes a busbar current differential relay in conjunction with a current transformer(CT) compensating algorithm irrespective of the level of the remanent flux. The compensating algorithm detects the start of first saturation if the third-difference function of the current exceeds the threshold; it estimates the core flux at the first saturation start by inserting the negative value of the third-difference function of the current into the magnetization curve; thereafter, it calculates the core flux during the fault and compensates the distorted current using the magnetization curve. The algorithm estimates the correct secondary current irrespective of the level of the remanent flux and needs no saturation point of the magnetization curve. The proposed relay can improve not only security of the relay on an external fault with CT saturation but sensitivity of the relay on an internal fault; the relay can improve the operating speed on n internal fault with CT saturation. This paper concludes by implementing the relay into a digital signal processor based prototype relay.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.7
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• pp.3566-3582
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• 2019

In intelligent warehouse picking system, the allocation of tasks has an important influence on the efficiency of the whole system because of the large number of robots and orders. The paper proposes a method to solve the task allocation problem that multi-robot task allocation problem is transformed into transportation problem to find a collision-free task allocation scheme and then improve the capability of task processing. The task time window and the power consumption of multi-robot (driving distance) are regarded as the utility function and the maximized utility function is the objective function. Then an integer programming formulation is constructed considering the number of task assignment on an agent according to their battery consumption restriction. The problem of task allocation is solved by table working method. Finally, simulation modeling of the methods based on table working method is carried out. Results show that the method has good performance and can improve the efficiency of the task execution.

• Smart Structures and Systems
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• v.23 no.1
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• pp.71-79
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• 2019

In general, it may be advantageous to measure the pressure pulsation near a valve to detect a valve defect in a linear compressor. However, the acceleration signals are more advantageous for rapid classification in a mass-production line. This paper deals with the performance improvement of fault classification using only the compressor-shell acceleration signal based on the relation between the refrigerant pressure pulsation and the shell acceleration of the compressor. A transfer function was estimated experimentally to take into account the signal noise ratio between the pressure pulsation of the refrigerant in the suction pipe and the shell acceleration. The shell acceleration signal of the compressor was modified using this transfer function to improve the defect classification performance. The defect classification of the modified signal was evaluated in the acceleration signal in the frequency domain using Fisher's discriminant ratio (FDR). The defect classification method was validated by experimental data. By using the method presented, the classification of valve defects can be performed rapidly and efficiently during mass production.

• Korean Journal of Food Science and Technology
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• v.54 no.4
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• pp.403-413
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• 2022

Evidence regarding the efficacy of Ginkgo biloba extract on cognitive function has been contentious. This study evaluated the effective period of G. biloba intake to improve cognition in the elderly. PubMed, EMBASE, Cochrane, Web of Science, and PsycArticles databases were searched for short-listing relevant studies. Twenty-five studies fulfilled the inclusion criteria. Cognitive efficacy was assessed based on the duration of intervention. G. biloba intake for 3-6 months statistically significantly affected cognitive function (SMD= -0.21; 95% CI -0.39, -0.03; p=0.02). However, the improvement in activities of daily living (ADLs) was not statistically significant. Thus, G. biloba intake for more than three months improves cognition in the elderly people with cognitive impairment and AD dementia without any safety risk. Intake for up to six months does not improve ADLs significantly in mild to moderate dementia patients.

• The Journal of Korea Robotics Society
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• v.18 no.4
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• pp.403-408
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• 2023

In this paper, we introduce the results of the development of a care robot for the safe lifting and transportation of bedridden patients with difficulty moving by themselves, especially, in medical facilities. The purpose of the developed patient transfer robot is to improve the convenience of care givers and enhance the safety and comfort of care recipients by facilitating patient lifting and patient transfer tasks by applying robot technology. In order to implement the lifting function, a hoist was designed and developed, and a sway control and rollover warning system were included in the hoist module as product differentiators. In addition, in terms of implementing the transfer function, an omnidirectional movement mechanism to improve operability in confined spaces and an active safety system to prevent collisions were developed. The function of the developed patient transfer robot was verified through performance evaluation by an authorized testing agency.

• Therapeutic Science for Rehabilitation
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• v.4 no.2
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• pp.33-50
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• 2015

Objective : This study was conducted to determine various interventions in accordance with the recovery and cognitive processes in order to improve executive function in stroke patients through a systematic review. Methods : The literature search focused on Level I-IV studies published between January 1996 and April 2015 for 20 years in electronic databases(e.g. MEDLINE, SCOPUS, RISS). The keyword search terms were 'Stroke', 'Executive function', 'Executive function deficit', 'Occupational therapy', 'Rehabilitation', 'Remedial', 'Compensatory' and 'Education'. Result : A total of 13 articles were appraised using the hierarchy of levels of evidence-based practice and 6 Level I evidence articles, 1 Level II articles, 2 Level III articles and 4 Level IV articles. Each intervention improved executive function but was different in degree of generalization. Conclusion : Through this systematic review, we found that there are a variety of applied interventions improving executive function in stroke patients and are different in effect depending on methods of interventions. This study provided evidences to occupational therapists for the clinical practice of interventions to improve executive function in stroke patients.

• Bulletin of the Korean Mathematical Society
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• v.49 no.2
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• pp.367-372
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• 2012

Taking the integrated Chebyshev-type counting function of the appropriate order, we improve the error term in Park's prime geodesic theorem for hyperbolic manifolds with cusps. The obtained estimate coincides with the best known result in the Riemann surfaces case.

• Bulletin of the Korean Mathematical Society
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• v.46 no.6
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• pp.1189-1200
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• 2009

The main purpose of this paper is to deal with the uniqueness of meromorphic functions sharing sets concerning small functions. We obtain two main theorems which improve and extend strongly some results due to R. Nevanlinna, Li-Qiao, Yao, Yi, Thai-Tan, and Cao-Yi.