• 정보통신설비학회논문지
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• 제4권1호
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• pp.23-29
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• 2005

This study is about designing mobile phone display in consideration of elder people's preferences by reason of their optical weakness. The research is closely connected with designing user-friendly interface by considering user characteristics. The criteria for first experiment are font sizes, font types, line spacing and background colors. With the experiment result, relative importance of each attribute and subjective preference are investigated by conjoint analysis. Secondly, an optimal display design for elder people is presented by response surface method on the basis of the result of conjoint analysis, other statistical analyses, and user interviews.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1685-1686
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• 2008

Almost all existing controllers for nonholonomic mobile robots are designed without considering the motor dynamics. This is because the presence of the motor dynamics increases the complexity of the system dynamics, and makes difficult the design of the controller. In this paper, we propose a simple controller for trajectory tracking of mobile robots including motor dynamics. For the simple controller design, the dynamic surface control methodology is applied and extended to multi-input multi-output systems (i.e., mobile robots) that the number of inputs and outputs are different. Finally, simulation results demonstrate the effectiveness of the proposed controller.

• 한국군사과학기술학회지
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• 제17권4호
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• pp.501-509
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• 2014

In NCW(Network Centric Warfare) environment, mobile nodes communicate through wireless link. But wireless link provides limited networking performance due to signal interferences or mobility of nodes. So it is quite challenge to acquire enough networking resources and use the resources efficiently. In this paper, we have proposed a P2P based tactical information sharing system which provides satisfactory visual information playout for mobile nodes(i.e., military personnel, vehicle,..) in NCW environment. Our proposed system consists of two components. One is caching-enabled switch which stores tactical information segments at its internal storage and then transports them to mobile nodes when require. Another is centralized scheduling algorithm which exploits networking resources more efficiently. To validate performance of proposed system, we performed series of experiments in wireless network testbed. Results show improved performance in terms of segment-missing ratio, networking resources usage, sharing time, and number of simultaneous playout mobile nodes with acceptable playout continuity(i.e., over 95%).

• 대한의생명과학회지
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• 제27권4호
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• pp.310-316
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• 2021

Mobile phones used by healthcare workers are not only an indicator of the contamination of healthcare associated bacteria, but can also be another source of infection. The number and time of handwashing, mobile phone operation time and disinfection were highly relation with the bacterial contamination on the surface of mobile phone. Healthcare associated bacteria isolated from the mobile phone surface were 28 MRCoNS (48.3%), 14 S. aureus (24.2%), 3 MRSA (5.2%), 5 A. baumannii (8.6%), 3 MRAB (5.2%), 3 Entrococcus spp. (5.1%), 2 Pantoea spp. (3.4%), 2 A. lowffii (3.4%), 1 E. cloacae (1.7%), 1 P. stutzeri (1.7%), and P. mirabillis (1.7%). For isolation according to department, 2 MRAB from the emergency room and 1 MRSA from intensive unit, the radiology team and the rehabilitation medical team, respectively were isolated. As a result of the relation of isolates from the department of patient contact (ER, RT, GW, CP, ICU, RMT), the bacterial isolation rate was 75% and the department of patient non-contact (MRT) was 10%.

• 한국광학회:학술대회논문집
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• 한국광학회 2006년도 하계학술발표회 논문집
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• pp.79-80
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• 2006

• 전자공학회논문지S
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• 제34S권10호
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• pp.71-79
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• 1997

This paper introduces a methodology of the precise control of a mobile/task robot using visual information captured bythe camera attached at the hand of the task robot. The major problem residing in the precise control of mobile/task robot is providing an accurate and stable base for the task robot through the precise control of mobile robot. On account of uncertainties on the surface, the precise control of mobile robot is not feasible without using external position sensor. In this paper, the methodology for the precise control of mobile robot is proposed, which recognizes the position of mobile robot using the camera attached at the hand of the task robot. While the task robot is approaching to an assembly part, the position of mobile robot is measured using the line correspondence between the image capturesd by the camera and the real assembly part, and using the kinematic transformation from the hand of the task robot to the mobile robot. To verify the solidness of this method, experimental data for the measurement of camera position/orientation and for the precise control of mobile robot using measurement are shown.

• 한국기계가공학회지
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• 제16권3호
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• pp.119-124
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• 2017

Machining optimization using typical computer-aided manufacturing (CAM) software mainly depends on tool paths, and it is impossible to predict the behavior of material or cutting force. In this paper, cutting force analysis simulation is performed on the Unibody Case of a mobile phone with the aim of optimizing cutting-force-based machining using the Third Wave Systems' AdventEdge Production Module. Machining time after optimization was shortened by 42% for roughing compared to pre-optimization, and actual machining time was reduced by 36.8%. For finishing, machining time was reduced by 92%, and actual machining time was reduced around 90%. A surface roughness analysis found that the post-optimization surface roughness was $1.16{\mu}m$ Ra, compared to a pre-optimization value of $1.75{\mu}m$ Ra.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.539-545
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• 2014

Styrene-acrylamide co-polymer was immobilized on porous partially sub-$2{\mu}m$ silica monolith particles and inner surface of fused silica capillary ($50{\mu}m$ ID and 28 cm length) to result in ${\mu}LC$ and CEC stationary phases, respectively, for separation of anomeric D-glucose derivatives. Reversed addition-fragmentation transfer (RAFT) polymerization was incorporated to induce surface polymerization. Acrylamide was employed to incorporate amide-functionality in the stationary phase. The resultant ${\mu}LC$ and CEC stationary phases were able to separate isomers of D-glucose derivatives with high selectivity and efficiency. The mobile phase of 75/25 (v/v) acetonitrile (ACN)/water with 0.1% TFA, was used for HPLC with a packed column (1 mm ID, 300 mm length). The effects of pH and ACN composition on anomeric separation of D-glucose in CEC have been examined. A mobile phase of 85/15 (v/v) ACN/30 mM sodium acetate pH 6.7 was found the optimized mobile phase for CEC. The CEC stationary phase also gave good separation of other saccharides such as maltotriose and Dextran 1500 (MW~1500) with good separation efficiency (number of theoretical plates ~300,000/m).

• 해양환경안전학회지
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• 제21권6호
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• pp.744-750
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• 2015

본 연구에서는 해상에서 선박의 외측 표면 검사를 위한 모바일 로봇의 개발에 대해 언급하였다. 해상에서 선체 측면에 대한 검사를 육안으로 진행하기 어려우며 이러한 검사를 효과적으로 수행하기 위해 모바일 로봇은 선체 측면에 부착되어 주행할 수 있는 기능을 갖추어야 한다. 이를 위해 선체 측면과의 부착력을 발생시키기 위해 영구 자석 모듈을 도입하였고, 곡면 주행 시 자기력의 변화를 최소화하는 구조로 설계를 하였다. 이러한 설계를 바탕으로 4개의 네오디움 자석, 4개의 구동바퀴, 영상 획득 모듈로 구성되는 모바일 로봇을 제작하였다. 제작된 로봇에 대해 선체와의 부착력을 확인하기 위한 하중 실험을 실시하였고, 주행이후 정지 시 측면 미끄럼 실험과 주행 속도 측정 실험을 실시하였다. 실험 결과 13 [Kgf]까지 선체와의 부착력을 유지할 수 있었고, 미끄러짐이 없는 하중은 8 [Kgf]까지였다. 주행 실험에서는 6.5 [A]의 전류에 대해 0.82 [m/s]의 속도로 주행할 수 있는 것을 확인하였다. 선박의 표면 검사를 위해 개발한 모바일 로봇의 특성 실험을 통해 로봇의 유용성을 확인할 수 있었다.

• International Journal of Control, Automation, and Systems
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• 제6권5호
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• pp.713-721
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• 2008

This paper presents the robust velocity estimation of an omnidirectional mobile robot using a polygonal array of optical mice that are installed at the bottom of the mobile robot. First, the velocity kinematics from a mobile robot to an array of optical mice is derived as an overdetermined linear system. The least squares velocity estimate of a mobile robot is then obtained, which becomes the same as the simple average for a regular polygonal arrangement of optical mice. Next, several practical issues that need be addressed for the use of the least squares mobile robot velocity estimation using optical mice are investigated, which include measurement noises, partial malfunctions, and imperfect installation. Finally, experimental results with different number of optical mice and under different floor surface conditions are given to demonstrate the validity and performance of the proposed least squares mobile robot velocity estimation method.