• Korean Journal of Acupuncture
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• 제20권1호
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• pp.71-90
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• 2003

The shoulder is the most flexible joint in human body, so many people suffer from the shoulder pain. In order to improve medical care about shoulder muscle disease, Myofascial Pain Syndrome(M.P.S) is compared with the oriental medical theory. The findings of this study are as follows; 1. Myofascial Pain Syndrome(M.P.S) is the sensory, motor, and autonomic symptoms caused by myofascial trigger points. For the objectivity of the oriental medical theory, practical application is necessary. 2. The meridian and meridian-muscle of the shoulder is su-sam-yang(手三陽), su-sam-um(手三陰). Meridian-muscle theory is similar to anatomical muscle and myofascia. 3. There is similarity in the trigger point and Ashi(阿是)-point, taut band and palpable tender-point(硬結), referred pain and Hangki(行氣). In this study, myofacial pain syndrome is similar to the oriental medical theory. If myofacial pain syndrome is applicated in treatment, the cure of shoulder pain and objectivity of the oriental medical theory is improved.

• 한국생산제조학회지
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• 제18권6호
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• pp.642-651
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• 2009

The history of excavator design is not long enough which still causes most of the design considerations to be focused on static analysis or simple functional improvement based on static analysis. However, the real forces experiencing on each component of excavator are highly transient and impulsive. Therefore, the prediction and the evaluation of the movement of the excavator by dynamic load in the early design stage through the dynamic transient analysis of the excavator and ensuring of design technique plays an importance role to reduce development-cost, shorten product-deliver, decrease vehicle-weight and optimize the system design. In this paper, Commercial software DADS and ANSYS help to develop the track model of the crawler type excavator, and to evaluate the performance and the dynamic characteristics of excavator with various simulations. For that reason, the track of crawler type excavator is modelled with DADS Track Vehicle Superelement, and the reaction forces on the track rollers were predicted through the driving simulation. Also, the upper frame and cabin vibration characteristics, at the low RPM idle state, were evaluated with engine rigid body modelling. And flexibility body effects were considered to determine the more accurate joint reaction forces and accelerations under the upper frame swing motion.

• 전기학회논문지
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• 제57권4호
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• pp.706-714
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• 2008

In this paper, we suggest a practical and flexible system architecture for JTAG(Joint Test Action Group) protection of application processors. From the view point of security, the debugging function through JTAG port can be abused by malicious users, so the internal structures and important information of application processors, and the sensitive information of devices connected to an application processor can be leak. This paper suggests a system architecture that disables computing power of computers used to attack processors to reveal important information. For this, a user authentication method is used to improve security strength by checking the integrity of boot code that is stored at boot memory, on booting time. Moreover for user authorization, we share hard wired secret key cryptography modules designed for functional operation instead of hardwired public key cryptography modules designed for only JTAG protection; this methodology allows developers to design application processors in a cost and power effective way. Our experiment shows that the security strength can be improved up to $2^{160}{\times}0.6$second when using 160-bit secure hash algorithm.

• 로봇학회논문지
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• 제18권3호
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• pp.241-250
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• 2023

This paper describes the posture stabilization control of a bipedal transformer robot being developed for military use. An inverted pendulum model with a rectangular that considers the robot's inertia is proposed, and a posture stabilization moment that can maintain the body tilt angle is derived by applying disturbance observer and state feedback control. In addition, vertical force and posture stabilization moments that can maintain the body height and balance are derived through QP optimization to obtain the necessary torques and vertical force for each foot. The roll and pitch angles of the IMU sensor attached to the robot's feet are reflected in the ankle joint to enable flexible adaptation to changes in ground inclination. Finally, the effectiveness of the proposed algorithm in posture stabilization is verified by comparing and analyzing the difference in body tilt angle due to disturbances and ground inclination changes with and without algorithm application, using Gazebo dynamic simulation and a down-scale test platform.

• ETRI Journal
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• 제45권5호
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• pp.887-898
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• 2023

Aerial base stations (ABSs) seem promising to enhance the coverage and capacity of fifth-generation and upcoming networks. With the flexible mobility of ABSs, they can be positioned in air to maximize the number of users served with a guaranteed quality of service (QoS). However, ABSs may be overloaded or underutilized given inefficient placement, and user association has not been well addressed. Hence, we propose a three-dimensional ABS placement scheme with a delay-QoS-driven user association to balance loading among ABSs. First, a load balancing utility function is designed based on proportional fairness. Then, an optimization problem for joint ABS placement and user association is formulated to maximize the utility function subject to statistical delay QoS requirements and ABS collision avoidance constraints. To solve this problem, we introduce an efficient modified gray wolf optimizer for ABS placement with a greedy user association strategy. Simulation results demonstrate that the proposed scheme outperforms baselines in terms of load balancing and delay QoS provisioning.

• 한국운동역학회지
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• 제26권2호
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• pp.167-174
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• 2016

Objective: The purpose of this study was to determine the interrelationship between ranges of motion of the knee and ankle joints on the sagittal plane and the attenuation magnitude of impact shock at high frequency (9~20 Hz) in the support phase during downhill running. Method: Fifteen male heel-toe runners with no history of lower extremity injuries were recruited for this study (age, $25.07{\pm}5.35years$; height, $175.4{\pm}4.6cm$; mass, $75.8{\pm}.70kg$). Two uniaxial accelerometers were mounted to the tuberosity of tibia and sacrum, respectively, to measure acceleration signals. The participants were asked to run at their preferred running speed on a treadmill set at $0^{\circ}$, $7^{\circ}$, and $15^{\circ}$ downhill. Six optical cameras were placed around the treadmill to capture the coordinates of the joints of the lower extremities. The power spectrum densities of the two acceleration signals were analyzed and used in the transfer function describing the gain and attenuation of impact shock between the tibia and the sacrum. Angles of the knee and ankle joints on the sagittal plane and their angle ranges were calculated. The Pearson correlation coefficient was used to test the relationship between two variables, the magnitude of impact shock, and the range of joint angle under three downhill conditions. The alpha level was set at .05. Results: Close correlations were observed between the knee joint range of motion and the attenuation magnitude of impact shock regardless of running slopes (p<.05), and positive correlations were found between the ranges of motion of the knee and ankle joints and the attenuation magnitude of impact shock in $15^{\circ}$ downhill running (p<.05). Conclusion: In conclusion, increased knee flexion might be required to attenuate impact shock during downhill and level running through change in stride or cadence while maintaining stability, and strong and flexible ankle joints are also needed in steeper downhill running.

• 한국건설순환자원학회논문집
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• 제7권4호
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• pp.323-332
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• 2019

건설 방수재로 사용되는 고무아스팔트 씰재에 대한 한국 및 중국의 공동 품질관리 규정 제정을 위해 양국의 재료 및 품질기준 현황을 조사하고, 향후 방향을 제시한 연구다. 고무아스팔트 씰재에 대한 한중 무역교류가 추진되고 있 있으나, 국가 간에 제시된 품질기준이 달라 제품에 대한 품질 검증의 어려움이 있고, 이를 해소하기 위해 양국의 현황을 파악하여 공동 품질관리 규정 제정의 필요성을 제시하였다 .한국과 중국의 고무아스팔트 씰재에 대한 구성 재료 비교, 품질관리 기준(성능평가 항목)의 비교 결과, 구성 재료에 있어서 방수 성능을 발현하는 주성분 원료인 "아스팔트와 고무"의 사용 비율에 차이가 있고, 부원료(충전제, 증점제, 접착제 등)의 사용 소재 종류도 다르게 나타났으며, 성능평가 항목에 있어서도 양국의 요구 성능 항목이 크게 다르다는 것을 파악되었다. 이러한 문제을 해소하기 위하여 일반적으로 ISO(국제표준기구 : International Organization for Standardization)에서 제시한 표준 기준을 활용하는 등의 대안이 있으나 고무 아스팔트 씰재에 대한 방수재 ISO 표준은 전무하며, 한중간 무역 교류를 위하여 ISO 규격을 제정하기에는 소모되는 시간이나 비용에 따른 경제적 여건이 불합리한 상황이다. 이에 본 연구에서는 한중 양국 간에 공동으로 적용할 수 있는 품질규격을 제정하여 상호 무역 교류 시 이를 적용함으로써 제품에 대한 물성파악이 용이한 국제공동규격 제정을 위한 성능평가 요소로써 주요 성능 항목으로 "화학저항성능, 투수저항성능, 온도안정성능, 습윤면 부착성능"을, 부가 성능 항목으로 "균열 거동 대응성능", "점도", "고형분" 등 7가지 항목을 제시하였다.

• 마이크로전자및패키징학회지
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• 제18권2호
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• pp.63-67
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• 2011

본 연구에서는 interlayer로 Sn을 사용하여 경성 인쇄 회로 기판(Rigid printed circuit board, RPCB)과 연성 인쇄 회로 기판(Flexible printed circuit board, FPCB) 간의 열압착 접합(Thermo-compression bonding) 조건을 최적화하는 연구를 진행하였다. 접합에 앞서 FPCB를 다양한 온도와 시간조건 하에서 Sn이 용융된 솔더 배스 안에서 침지(Dipping) 공정을 수행하였고, 열압착법을 이용하여 FPCB와 RPCB의 접합을 수행하였다. FPCB/RPCB 접합부의 접합 강도를 $90^{\circ}$ 필 테스트(Peel test)를 이용하여 측정하였다. 그 결과 $270^{\circ}C$, 1s의 침지 조건에서 FPCB의 polyimide(PI)와 Cu 전극 계면에서 파단되고, 이때, 최대 박리 강도를 얻었다. FPCB와 RPCB의 열압착 접합시 주요 변수로는 압력, 온도, 시간이 있으며, 특히 온도의 증가에 따라 접합 강도가 크게 증가하였다. 접합부 계면 관찰 결과, 접합 온도와 시간이 증가함에 따라 접합 면적이 증가하였으며, 이로 인해 접합 강도가 증가하는 것으로 사료된다. 필 테스트 과정에서 나타나는 F-x(Forcedisplacement) 곡선을 토대로 산출한 파괴 에너지와 접합 강도는 $280^{\circ}C$, 10s의 접합 조건에서 가장 높게 나타났으며, 이 조건이 최적 접합 조건으로 도출되었다.

• 한국해안해양공학회지
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• 제7권2호
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• pp.156-162
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• 1995

스커트의 유연성을 고려한 2차원 오일붐 모델에 대한 수치해법을 개발하였다. 본 수치모델에서는 부체를 강체로, 스커트를 장력이 걸려 있는 막으로, 스커트의 아래끝엔 집중질량이 놓여 있다고 가정하였다. 유동은 포텐셜이라고 가정하였으며 부체와 스커트의 연결부에서는 변위가 연속이라는 운동학적 조건을 그리고 스커트의 아래끝에는 집중질량에 대한 동력학적인 조건을 부가하였다. 수치해법은 선형포텐셜유동 이론에 근거한 Green 함수방법에 기초를 두고 있다. 스커트의 변형을 미리 알 수 없으므로 방사 포텐셜(radiation potential)과 부체의 변위 그러고 스커트의 변형을 동시에 구하는 방식을 택하였다. Green 정리를 적용하여 얻은 적분방정식과 부체의 운동방정식 그리고 스커트의 변형 관계식을 이산화하여 방사포텐셜과 부체의 변위 그리고 스커트의 변위에 대한 선형대수 방정식을 얻었다. 수치계산결과에 의하면 스커트의 유연성이 부체의 운동응답을 다소 줄일 수 있으며 부체의 공진체계를 바꿀 수 있음을 확인하였다. 그리고 오일붐의 운동응답특성에 영향을 주는 인자들 중에서 스커트의 길이와 집중질량을 파라미터로 하여 오일붐 모델의 운동응답특성을 비교해 보았다. 스커트가 유연한 경우와 스커트가 강체인 경우의 저주파수 극한해는 거의 일치하고 있어 수치해의 타당성을 간접적으로 확인할 수 있었다.

• 유통과학연구
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• 제14권7호
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• pp.71-81
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• 2016

Purpose - Because creativity, which is an intangible resource embedded within the company, can offer a competitive advantage, most companies have an interest in promoting creativity among their employees and division(e.g., marketing organization). Creativity renders a sustainable competitive advantage to a firm because it is a strategic resource that is valuable, flexible, rare, and imperfectly imitable or substitutable. Although most companies broadly recognize the importance of creativity, the methods for developing creativity remain elusive. Therefore, the present study investigates how to structure incentives to motivate employees to be more creative and how to develop tools to facilitate creativity. In detail, the present study aimed to examine the relationship between the regulatory focus of marketing organizations(e.g., promotion focus vs prevention focus) and creativity of marketing organizations. In addition, the present study set out to examine the moderating role of interaction of financial reward and creative training in addition to investigating the direct relationship between creativity and regulatory focus in New Product Development(NPD) context. Research design, data, and methodology - The data used to test the hypotheses are drawn from a survey of full time NPD project members(including project manager, designer, engineer, and marketer). The present study utilized data obtained mainly from a database compiled by the Korea Investors Service-Financial Analysis System which provides comprehensive corporate and financial information on firms listed on the Korea Stock Exchange. A study population comprising 1,000 South Korean firms was obtained from this database. We selected 864 firms from the database, and the firms have experiences of new product development project. We collected a total of 162 responses, for a 18.8% response rate. After we excluded 14 questionnaire because of incomplete responses, a total of 148 questionnaire remained(final response rate: 17.1%). Working with a sample of 148 responses in South Korea, hierarchical moderated regression is employed to test research hypotheses(

The relationship between promotion focus and creativity of marketing organization,

The relationship between prevention focus and creativity of marketing organization,

The moderating effect of joint influences(interaction between financial rewards and creativity training) on the relationship between promotion focus creativity of marketing organization,

The moderating effect of joint influences(interaction between financial rewards and creativity training) on the relationship between prevention focus creativity of marketing organization). SPSS 18.0 and AMOS software were used in the data analysis. Results - The empirical study confirmed that promotion focus of marketing organization is positively related to creativity of marketing organization. Also, prevention focus of marketing organization is positively affected to creativity of marketing organization. In addition, the interaction between financial rewards and creativity training moderated the relationship between regularity focus(e.g.), promotion focus vs prevention focus) and creativity of marketing organization. These results suggest that managers can improve the performances of their creative efforts by providing the use of financial rewards and creativity training in combination. Conclusion - Based on results of this study that examine the effects of regulatory focused creative efforts on creativity of marketing organization, promotion focus is helpful with marketing organizations to enhance their service innovation and performance. Prevention focused organization should allow monetary rewards and creativity training to increase their creativity for innovation of new products.