• ETRI Journal
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• 제40권5호
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• pp.604-612
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• 2018

To solve the problem of unbalanced loads and the short network lifetime of heterogeneous wireless sensor networks, this paper proposes a node-selection algorithm based on energy balance and dynamic adjustment. The spacing and energy of the nodes are calculated according to the proximity to the network nodes and the characteristics of the link structure. The direction factor and the energy-adjustment factor are introduced to optimize the node-selection probability in order to realize the dynamic selection of network nodes. On this basis, the target path is selected by the relevance of the nodes, and nodes with insufficient energy values are excluded in real time by the establishment of the node-selection mechanism, which guarantees the normal operation of the network and a balanced energy consumption. Simulation results show that this algorithm can effectively extend the network lifetime, and it has better stability, higher accuracy, and an enhanced data-receiving rate in sufficient time.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2643-2645
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• 2001

In this paper, a problem of limited sampling time that occurs essentially in digital data acquisition system is discussed. Low sampling frequency and a lot of processed data in micro-controller interferes normal operation of the controller from acquiring information in some case. To settle this problem, we design the sub-system which consists of a new simple micro-controller. which is managed the particular sensor making the trouble to main-controller system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1106-1107
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• 2007

Planar magnetic based design technologies have been widely applied to power design for better cooling and ease of fabrication. The planar transformer and the planar inductor have a low profile characteristics compare to the conventional transformer which would be more cubical in volume. High frequency operation of magnetic components is a main key to achieve high power density of the power module. However, at a high frequency, the skin effect and the proximity effect have to be considered very significantly in magnetic design and also the parasitics in the converter cannot be ignored. This paper deals with the design and the experiment of planar integrated magnetic component. The optimal design for planar magnetics is summarized.

• International journal of advanced smart convergence
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• 제8권2호
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• pp.1-7
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• 2019

Drones will evolve from military to personal or social purposes. How can people socially interact with a drone that is familiar to them? This study explored the social proximity of human drone interaction with safety glass wall between participants and drone. The experiment results showed that drone's altitude, size and gender factor did not significantly affect social proxemics as to what extent participants got closer to hovering drones by the limitation of the distance from the safety wall. However, it shows a tendency that participants more closely approached an eye-level drone compared with an overhead drone, and females tended to approach more closely males. This study consequently demonstrated that most participants are nearly ready to allow a near field operation of social drone under safe conditions.

• Journal of Information Processing Systems
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• 제19권4호
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• pp.407-416
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• 2023

In order to effectively relieve the traffic pressure of the city, ensure the smooth flow of freight and promote the development of the logistics industry, the selection of appropriate port logistics location is the basis of giving full play to the port logistics function. In order to better realize the selection of port logistics, this paper adopts the entropy weight method to set up a multi-dimensional evaluation index, and constructs the evaluation model of port logistics location. Then through the actual case, from the environmental dimension and economic competition dimension to make choices and analysis. The results show that port d has the largest logistics competitiveness and the highest relative proximity among the three indicators of hinterland city economic activity, hinterland economic structure, and port operation capacity of different port logistics locations, which has absolute advantages. It is hoped that the research results can provide a reference for the multi-dimensional selection of port logistics site selections.

• Clinics in Shoulder and Elbow
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• 제26권4호
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• pp.445-454
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• 2023

The Latarjet procedure is a surgical procedure that can effectively restore glenohumeral stability, especially in patients with anterior shoulder instability and glenoid bone loss. Many studies have shown comparable clinical outcomes between patients undergoing the arthroscopic Latarjet procedure and those undergoing traditional open methods or other glenohumeral joint stabilization procedures. However, the arthroscopic Latarjet procedure is a challenging technique due to the unfamiliar portal placements, proximity of neurovascular structures, and serious postoperative complications. The arthroscopic Latarjet procedure has not yet been widely applied, and a clear understanding of the anatomical structure and the precise methods is required prior to operation performance. Satisfactory clinical outcomes can be achieved by thorough preoperative planning and proper implant fixation methods.

• 한국항공우주학회지
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• 제43권10호
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• pp.902-909
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• 2015

본 논문에서는 인공위성 근접운용을 위한 단일 영상 기반 상대항법에 대한 연구를 수행하였다. 추적 위성은 하나의 카메라 센서만을 이용하여 표적 위성을 관측하고 영상추적을 통해 표적 위성의 위치 정보를 얻게 된다. 그러나 단일 영상만을 이용할 경우, 표적과의 상대 거리에 해당하는 깊이 정보를 얻기 힘들다. 이러한 문제를 해결하기 위해 능동 윤곽 기법을 영상 추적에 적용하였다. 능동 윤곽 기법을 통해 표적의 이미지 크기를 얻을 수 있고 이러한 형상 정보를 바탕으로 상대 거리를 간접적으로 계산할 수 있다. 두 인공 위성이 상대 운동을 하는 우주환경을 구현하고 가상의 카메라 영상을 생성하기 위해 3차원 가상현실이 이용되었다. 추적 위성은 UKF를 이용하여 표적 위성에 대한 상대위치를 추정하면서 글라이드슬로프 접근 기법을 이용하여 표적 위성에 근접한다. 상대항법의 성능을 분석하기 위해서 폐 루프 시뮬레이션을 수행하였다.

• 한국전자파학회논문지
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• 제14권1호
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• pp.75-80
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• 2003

본 논문에서는 기존 원형 링 마이크로스트립 슬롯 안테나의 방사소자 일부를 제거하고, 길이가 서로 다른 십자슬롯을 부설하여 원형편파를 구현하고, 안테나 크기를 소형화시킨 새로운 구조의 안테나를 제안하였다. 급전구조는 입력단 설계가 간단하고 정합이 쉬운 전자파 결합방식을 사용하였고, Ansoft HFSS V8.0으로 최적화한 후 제작 및 측정하였다. 제안된 안테나는 GPS(1.5 GHz)대역에서 1.9 %의 축비 대역폭(AR$\leq$3 dB)을 나타내었고, LHCP$.$RHCP 각각의 구조에서 7.74 %의 임피던스 대역폭(VSWR$\leq$2)을 나타내었다. 이는 기존의 원형링 마이크로스트립 슬롯 안테나의 임피던스 대역폭 및 축비 특성을 보다 더 개선한 것이다.

• 한국정밀공학회지
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• 제20권1호
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• pp.107-117
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• 2003

Polishing a die that has free-form surfaces is a time-consuming and tedious job, and requires a considerable amount of high-precision skill. In order to reduce the polishing time and cope with the shortage of skilled workers, an automatic polishing robot system was developed. The polishing robot system is composed of two subsystems, a three-axis machining center and a two-axis polishing head. The machining center is controlled by a FANUC controller, and the polishing head by DSP controller. The system has five degrees of freedom and is able to keep the polishing tool normal to the die surface during operation. To easily operate the developed polishing robot system, this study developed an integrated operating program in the Windows environment. The program consists of five modules: a polishing data generation module, a code separation module, a polishing module, a graphic simulator module, and a teaching module. And, the automatic teaching system was developed to easily obtain teaching data and it consists of a three dimensional joystick and a proximity sensor. Also, to evaluate the performance of the integrated operating program and the polishing robot system, polishing experiments of a die of shadow mask were carried out.

• 한국소음진동공학회논문집
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• 제24권6호
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• pp.476-482
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• 2014

The stress analysis of the pipeline is required in any kind of plant for its safe operation. For this, the displacement vibration data measured at many locations of the pipeline should be provided. In reality, the installation of the non-contact type displacement sensors such as laser displacement sensors or eddy current type proximity sensors in a narrow and confined region in the vicinity of the pipeline is almost impracticable. In this work, the general purpose piezo-ceramic accelerometers were attached on the measuring points on the pipeline and the acceleration vibration signal was acquired. The measured acceleration signal was low pass filtered and then downsampled. The resulting acceleration signal was transformed into both the time-domain and frequency-domain displacement signal utilizing the fast Fourier transform techniques. All the procedures are presented in detail. It is demonstrated that the measurement of the pipeline acceleration by using contact type accelerometers can be made for the purpose of providing the required displacement data for the stress analysis of the pipeline.