• Journal of Electrical Engineering and Technology
• /
• 제13권2호
• /
• pp.943-952
• /
• 2018

This paper presents a new type of absolute rotary encoder system based on the affine n-digit N-ary gray code. A brief comparison of the existing encoder systems is carried out in terms of resolution, encoding and decoding principles and number of sensor heads needed. Using the proposed method, two different types of encoder disks are designed, namely, color-coded disk and grayscale coded disk. The designed coded disk pattern is used to manufacture 3 digit 3 ary and 2 digit 5 ary grayscale coded disks respectively. The manufactured disk is used with the light emitter and photodetector assembly to design the entire encode system. Experimental analysis is done on the designed prototype with LabVIEW platform for data acquisition. A comparison of the designed system is done with the traditional binary gray code encoder system in terms of resolution, disk diameter, number of tracks and data acquisition system. The resolution of the manufactured system is 3 times higher than the conventional system. Also, for a 5 digit 5 ary coded encoder system, a resolution approximately 100 times better than the conventional binary system can be achieved. In general, the proposed encoder system gives $(N/2)^n$ times better resolution compared with the traditional gray coded disk. The miniaturization in diameter of the coded disk can be achieved compared to the conventional binary systems.

• 대한토목학회논문집
• /
• 제34권5호
• /
• pp.1443-1454
• /
• 2014

본 연구는 레이더 강우와 분포형 수문모형의 공간해상도가 매개변수 추정 및 강우-유출 모의에 미치는 영향을 분석하였다. 레이더 강우는 비슬산 S밴드 이중편파 강우레이더에서 2012년 관측된 강우사상을 대상으로, R-KDP, R-Z, R-ZDR의 관계식에 의해 추정된 레이더 강우를 지상관측 강우와 비교하였다. 세 가지 강우 추정식에 의한 레이더 강우를 지상 관측 강우와 비교 시 유역 평균에 대해서는 모두 높은 일치도를 보였으며, 이는 지상 관측 강우에 대한 레이더 강우 보정의 영향으로 판단되었다. 그 중에서도 R-KDP에 의한 추정 강우가 비교적 높은 정확도를 보였으며, 이를 강우-유출 모형의 입력자료로 적용하였다. 강우-유출 모형으로는 GRM (grid based rainfall-runoff model) 모형을 이용하여, 낙동강 수계 금호강 유역을 대상으로, 200m, 500m, 1000m의 공간해상도로 입력자료를 구축하였다. 또한, 범용 매개변수 최적화 모형인 PEST(model independent parameter estimation tool)로 초기 포화도, 지표면 조도계수 및 토양 투수계수의 보정계수를 각 공간해상도 및 호우사상 별로 추정하였다. 매개변수 추정 결과, 200m 공간해상도 모형에서는 비교대상 강우사상에 대해 지표면 조도계수와 토양 투수계수 관련 보정계수가 비교적 안정적으로 추정되었으나, 500m, 1000m 공간해상도 모형에서는 강우사상에 따라 매개변수의 최적 추정 값의 변동이 확인되었다. 초기 포화도는 강우사상 별, 공간해상도 별로 일정한 경향을 보이지 않았다. 또한, 200m와 1000m 공간해상도에 대해 최적화된 매개변수를 다른 공간해상도에 적용한 결과, 1000m 공간해상도에 대해 보정된 매개변수를 200m 공간해상도 모형에 적용하면 첨두 홍수량이 증가하는 경향이 있었다.

• 제어로봇시스템학회논문지
• /
• 제10권5호
• /
• pp.458-463
• /
• 2004

This paper presents a fast IA(integer ambiguity) resolution method that determines the IA within short epochs with guaranteed reliability. Based on the fact that the search volume and the cost function are influenced by the selection of primary IAs in the plane intersection method, an IA resolution method is proposed that evaluates IA candidates repeatedly in an epoch with different combinations of primary IAs. In order to guarantee the reliability of the resolved IA with a certain probability, an inequality condition for selecting differencing operator is derived. Experiment results show that the proposed method consistently provides the true IA estimates within short time.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
• /
• pp.783-786
• /
• 2004

We have developed a 470 x 235ppi poly-Si TFT LCD with a novel pixel arrangement, called HDDP (Horizontally Double-Density Pixels), for high-resolution 2D and 3D autostereoscopic display. 3D image quality is especially high in a lenticular-lens-equipped 3D mode because both horizontal resolution and vertical resolution are high, and because these resolutions are equal. 3D and 2D images can be displayed simultaneously in the same picture. In addition, 3D images can be displayed anywhere and 2D characters can be made to appear at different depths with perfect legibility. No switching of 2D/3D modes is necessary, and the design's thin and uncomplicated structure makes it especially suitable for mobile terminals.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
• /
• pp.234-239
• /
• 1993

Most of the control problem is for the redundant manipulators use the pseudo-inverse control, thit is, the redundancy is resolved by the pseudo-inverse of the Jacobian matrix and then the controller is designed based on this resolution. However, this pseudo-inverse control has some problems when the redundant robot repeats the cyclic tasks. This is because the pseudo-inverse resolution is a local solution that generates the different configurations of the robot arm for the same hand position. Therefore it is necessary to find the global solution that maintains the optimal configuration of the robot for the repetitive tasks. In this paper, we want to propose a redundancy resolution method by the optimal theory that uses the calculus of variation. The problem formulations are : first to convert the optimal resolution problem to an optimal control problem and then to resolve the redundancy using the necessary conditions of optimal control.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 춘계학술대회 논문집
• /
• pp.828-831
• /
• 2005

In feature-based multi-resolution modeling, the features are rearranged according to a criterion for the levels of detail (LOD) of multi-resolution models. In this paper, two different LOD criteria are investigated and discussed. The one is the volumes of subtractive features, together with the precedence of additive features over subtractive features. The other is the volumes of features, regardless of whether the feature types are subtractive or additive. In addition, the algorithms to define and extract the LOD models based on the criteria are also described. The criterion of the volumes of features can be used for a wide range of applications in CAD and CAE in virtue of its generality.

• 한국항공운항학회지
• /
• 제18권3호
• /
• pp.27-33
• /
• 2010

The goal for the CD&R system is to predict that a conflict is going to occur in the future, communicate the detected conflict to a human operator, and, in some cases, assist in the resolution of the conflict situation. To provide insight into different methods of conflict detection and resolution, a literature review of previous research models and current developmental and operational systems was performed. This paper focuses only on the specific attributes of each model, not on the depth to which a model has been analyzed, validated, or accepted. Thus, care should be taken to remember that a model that seems to be simple according to our categorization scheme may be significantly more viable than an apparently sophisticated model.

• 한국안전학회지
• /
• 제23권4호
• /
• pp.30-35
• /
• 2008

The present study has been conducted to examine the effect of grid resolution on the predicted results for electric cable fire using pyrolysis model in FDS(Fire Dynamics Simulator, version 5). The grid independent test for different grid resolutions has been performed for a PE coating cable and the grid resolution is defined by the non-dimensional characteristic length of fire and mean grid size. The calculated maximum heat release rate and mean flame spread rate were almost constant for higher grid resolution of 20${\sim}$25 and the computing time for the grid resolution takes approximately 20hours to solve flame propagation with pyrolysis model. The geometrical simplification of a electric cable dose not greatly affect on the maximum heat release rate and flame spread rate and the rectangular approximation of cable shape gives acceptable result comparing with the round cable with stepwise grid.

• 한국광학회지
• /
• 제15권2호
• /
• pp.130-136
• /
• 2004

3차원 완전 결상에서 동적 배열 렌즈 방식을 사용하여 해상도를 향상시킬 때, 해상도 향상 특성을 조사하였다. 렌즈 배열의 이동 방향 및 이동 거리에 따라 관측 해상도가 달라짐을 컴퓨터 합성 완전 결상을 이용하여 보였다. 이를 통해 효율적으로 관측 해상도를 향상시킬 수 있는 렌즈 배열의 이동 조건을 찾을 수 있다.

• 아동학회지
• /
• 제22권4호
• /
• pp.69-84
• /
• 2001

Peer conflicts between school-aged children were observed to examine differences in conflict resolution strategies according to children's sex, peer status, and friendship. One hundred and forty eight dyads in 4th grade were selected for the study. The dyads' interactions in a small room while playing a Domino game were videotaped. Strategies the children used to resolve peer conflicts were analyzed by frequencies, and ANOVAs. School-aged children used reasoning and insistences to the partners frequently to resolve conflicts. Conflict resolution strategies were different by children's status among peers. Popular children used reasoning and listening more frequently. Rejected children used standing firm, behaving aggressively, ignoring, and withdrawing more frequently, and explaining and listening less frequently. Rejected children, especially rejected boys, used aggressive strategies more frequently.