• 한국생산제조학회지
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• 제19권1호
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• pp.145-155
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• 2010

This paper presents a new approach to obstacle avoidance for mobile robot in unknown or partially unknown environments. The method combines two navigation subsystems: low level and high level. The low level subsystem takes part in the control of linear, angular velocities using a multivariable PI controller, and the nonlinear position control. The high level subsystem uses ultrasonic and IR sensors to detect the unknown obstacle include static and dynamic obstacle. This approach provides both obstacle avoidance and target-following behaviors and uses only the local information for decision making for the next action. Also, we propose a new algorithm for the identification and solution of the local minima situation during the robot's traversal using the set of fuzzy rules. The system has been successfully demonstrated by simulations and experiments.

• 한국산림과학회지
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• 제104권1호
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• pp.117-126
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• 2015

시군구 단위 산림통계의 사회적 필요성에도 불구하고 자료의 부족으로 인하여 현실을 반영한 산림통계 산출이 어려운 상황에 있다. 따라서, 시군구 산림 통계 산출을 위하여 해당 시군구의 국가산림자원조사 자료와 주변 지역의 자료를 함께 활용하여 통계량의 오차 수준을 감소시키고 소면적 통계량이 해당 지역 산림의 지역적 특수성을 반영할 수 있는 새로운 소면적 통계산출 방법의 개발이 필요하다. 본 연구에서는 소면적 지역과 특성 구조가 유사하다는 가정을 만족하면서 통계산출을 위한 최소한의 표본점 개수를 확보하기에 적정한 공간 단위에 대한 연구를 수행하였다. 그리고 산림의 지역적 특성을 결정하는 주요 요인인 기후, 토양, 수종 구성 등의 동질성을 기준으로 구획된 확장시군구 기반의 합성추정법, 시 도 단위 자료를 이용하는 기본계획구 합성추정법, 인접 시군구 자료를 이용하는 이웃시군 합성추정법을 비교하고, 이 방법들을 통해 산출된 임목축적 통계의 지역적 특성 설명력과 상위 통계와의 관계에 대한 평가를 수행했다. 그 결과, 확장시군구 합성추정법이 기본계획구 합성추정과 이웃시군 합성추정보다 지역적 특성을 보다 잘 반영하는 통계를 산출하는 것으로 평가되었다. 또한 확장시군구 합성추정법을 통해 산출된 통계량은 시도 단위로 산출된 통계량의 95% 신뢰구간 내에 포함되었으며, 이웃시군 합성추정법에 의해 산출된 결과보다 시도단위 통계량과의 차이가 적게 발생하였다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제10권3호
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• pp.203-209
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• 2010

This paper presents a hierarchical fuzzy motion planner for humanoid robots in 3D uneven environments. First, we define both motion primitives and locomotion primitives of humanoid robots. A high-level planner finds a global path from a global navigation map that is generated based on a combination of 2.5 dimensional maps of the workspace. We use a passage map, an obstacle map and a gradient map of obstacles to distinguish obstacles. A mid-level planner creates subgoals that help the robot efficiently cope with various obstacles using only a small set of locomotion primitives that are useful for stable navigation of the robot. We use a local obstacle map to find the subgoals along the global path. A low-level planner searches for an optimal sequence of locomotion primitives between subgoals by using fuzzy motion planning. We verify our approach on a virtual humanoid robot in a simulated environment. Simulation results show a reduction in planning time and the feasibility of the proposed method.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송∙미디어공학회 2018년도 추계학술대회
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• pp.73-76
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• 2018

A Gaussian noise is caused by surrounding environment or channel interference when transmitting image. The noise reduces not only image quality degradation but also high-level image processing performance. The Non-Local Means (NLM) filter finds similarity in the neighboring sets of pixels to remove noise and assigns weights according to similarity. The weighted average is calculated based on the weight. The NLM filter method shows low noise cancellation performance and high complexity in the process of finding the similarity using weight allocation and neighbor set. In order to solve these problems, we propose an algorithm that shows an excellent noise reduction performance by using Summed Square Image (SSI) to reduce the complexity and applying the weighting function based on a cosine Gaussian kernel function. Experimental results demonstrate the effectiveness of the proposed algorithm.

• Journal of Dental Anesthesia and Pain Medicine
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• 제23권1호
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• pp.1-8
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• 2023

Backgrounds: Pain management is one of the most important factors affecting the success of pediatric dentistry. Therefore, new needle- and pain-free local anesthesia techniques have been developed in parallel with technological advancements. The purpose of this study is to compare the pain perception and dental anxiety levels associated with a needle-free injection system (Comfort-in^TM) and the classic needle method during treatment-required infiltration anesthesia in children. Methods: This randomized controlled crossover split-mouth clinical study included 94 children who required dental treatment with local anesthesia using a dental needle or needle-free injection system for the bilateral primary molars. The Wong-Baker Scale (WBS) was used to measure pain perception at different times, and the Modified Child Dental Anxiety Scale (MCDAS) was used to measure the anxiety level of the child. A statistical software package was used to process the data. Statistical significance was set at P < 0.05. Results: There was no significant difference between the needle-free injection system and dental needle method during the induction stage for filling and pulpotomy (P > 0.05). "Pain on postoperative 1st day" was similar in both types of anesthesia (P = 0.750). Conclusions: The needle-free injection system was as effective as the dental needle method. The Comfort-in^TM system was an acceptable alternative for patients during the postoperative period. Understanding how pain management may be provided during local anesthesia administration and a child's fear and anxiety regarding the dentist may lead to better dental compliance.

• 한국운동역학회지
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• 제31권1호
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• pp.30-36
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• 2021

Objective: The objective of the present study was to analyze the relationship between strength of the lower extremity's joints and their local dynamic stability (LDS) of gait in elderly women. Method: Forty-five elderly women participated in this study. Average age, height, mass, and preference walking speed were 73.5±3.7 years, 153.8±4.8 cm, 56.7±6.4 kg, and 1.2±0.1 m/s, respectively. They were tested torque peak of the knee and ankle joints with a Human Norm and while they were walking on a treadmill at their preference speed for a long while, kinematic data were obtained using six 3-D motion capture cameras. LDS of the lower extremity's joints were calculated in maximum Lyapunov Exponent (LyE). Correlation coefficients between torque of the joints and LyE were obtained using Spearman rank. Level of significance was set at p<.05. Results: Knee flexion torque and its LDS was negatively associated with adduction-abduction and flexion-extension movement (p<.05). In addition, ratio of the knee flexion torque to extension and LDS was negatively related to internal-external rotation. Conclusion: In conclusion, knee flexion strength should preferentially be strengthened to increase LDS of the lower extremity's joints for preventing from small perturbations during walking in elderly women.

• 농촌지도와개발
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• 제22권2호
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• pp.135-144
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• 2015

Competitiveness has been associated in the tourism literature as a crucial factor for the success of tourist destinations. This study is to develop indicators that measure destination competitiveness of rural tourism townships in Korea. It was conducted via a Delphi technique and the analytical hierarchy process method. After four rounds of discussions, the panel members reached consensus on a set of 27 indicators with three dimensions which are attractor (resource, infrastructure, and tourism products), assistance (tourism business assistance and value-added processing assistance), and planning and management (planning for development, capacity for management). This set of destination competitiveness indicators can serve as a starting point for devising a set of indicators at the local level in order to be useful rural tourism sector manager and administrators. The selected indicators are measurable, demand driven and practical to show the real performance in rural destination.

• 한국정보통신학회논문지
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• 제23권9호
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• pp.1049-1059
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• 2019

기존의 영역 병합을 통한 이미지 분할 방법에서는 이웃한 두 영역 사이의 정보만을 이용하여 병합 모델을 학습한다. 학습 과정에서는 두 영역 사이의 지역적인 정보뿐만 아니라 물체 정보와 같은 전역적인 정보 또한 활용 가능하므로 주어진 모든 정보를 활용하여 병합 모델의 성능을 높이는 것이 바람직하다. 본 논문에서는 학습 기반의 이미지 분할 알고리즘에서 학습 시에만 사용 가능한 특권정보를 활용하는 SVM+ 방법을 제안한다. 특권정보는 학습 시에만 사용 가능한 정보이므로 전통적인 지도학습 방법으로는 학습이 불가하다. SVM+와 같은 특권정보를 학습할 수 있는 구조를 통해 지역 정보뿐만 아니라 물체 정보를 포함하여 영역 간의 병합 여부를 결정하는 모델을 학습하였다. BSDS 500 데이터 세트와 VOC 2012 데이터 세트에서 벤치마크를 수행하였으며 대부분의 평가 지표에서 개선된 성능을 보여 주었다. 특히 학습 데이터 세트가 작은 경우에 기존의 알고리즘에 비해서 월등히 뛰어난 성능을 보인다.

• 한국산업보건학회지
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• 제33권3호
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• pp.291-297
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• 2023

Objectives: An epidemiological investigation was requested for a worker who developed COPD and IPF after long-term molding and firing at a domestic tile manufacturing site. We would like to share the results of the exposure assessment and the estimation of past work. Methods: The content of crystalline silica in four raw materials was analyzed, and the respirable fraction of crystalline silica and dust generated in the air from molding and firing workers and other processes were measured. The measurement and analysis method referred to the NIOSH method. Results: The crystalline silica content of the raw material was 24~47%. The concentration of crystalline silica in the molding and firing process workers and the surrounding area was at the level of the exposure standards set by the Ministry of Employment and Labor and ACGIH, and the respirable and total dust exposure levels were generally low. The crystalline silica concentration of the area samples measured to estimate past work was about twice as high as the exposure standard of the Ministry of Employment and Labor (0.05 mg/m3), and the exposure levels of respirable dust were also quite high at 0.903 and 1.332 mg/m3. Conclusions: It was confirmed that tile molding and firing workers are currently exposed to a fairly high level of crystalline silica, and a high level is also confirmed in area samples to estimate past work. In the past, it is judged that the level of exposure would have been much higher due to differences in production volume, working method, presence/absence of local ventilation facilities, and process layout. When working in such a working environment for a long time, respiratory diseases such as lung cancer, COPD, and IPF can occur.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제11권2호
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• pp.41-47
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• 2007

A fine segmentation algorithm is proposed for extracting objects in an image, which have both weak boundaries and highly non-convex shapes. The image has simple background colors or simple object colors. Two concepts, geometric attraction-driven flow (GADF) and edge-regions are combined to detect boundaries of objects in a sub-pixel resolution. The main strategy to segment the boundaries is to construct initial curves close to objects by using edge-regions and then to make a curve evolution in GADF. Since the initial curves are close to objects regardless of shapes, highly non-convex shapes are easily detected and dependence on initial curves in boundary-based segmentation algorithms is naturally removed. Weak boundaries are also detected because the orientation of GADF is obtained regardless of the strength of boundaries. For a fine segmentation, we additionally propose a local region competition algorithm to detect perceptible boundaries which are used for the extraction of objects without visual loss of detailed shapes. We have successfully accomplished the fine segmentation of objects from images taken in the studio and aphids from images of soybean leaves.