• 한국정보통신학회논문지
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• 제17권12호
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• pp.2937-2943
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• 2013

본 논문은 방사기저함수(Radial Basis Function)를 이용한 실시간 군집 시뮬레이션 프레임웍을 제안한다. 제안된 프레임웍에서는 군집이 존재하는 환경을 격자 구조로 모델링 한 후, 격자 구조 각 셀에 하나의 방향 벡터를 할당한 벡터필드를 선형 방사기저함수를 이용하여 실시간으로 합성한다. 방사기저함수를 통한 벡터필드 생성 시, 마우스를 통한 제어라인(Control line)을 이용하며, 이 벡터필드 위에서 군집들은 벡터 필드 흐름에 따라, 자신의 움직임을 결정한다. 방해물과의 충돌회피는 반발벡터필드로 모델링하여, 기존의 벡터필드에 오버레이 하여 이용하고, 다른 캐릭터와의 충돌회피는 lattice-bin 알고리즘에 빠른 충돌회피를 수행한다.

• 전기학회논문지P
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• 제65권3호
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• pp.171-177
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• 2016

Noise problem that occurs in living environment is a big trouble in the economic, social and environmental aspects. In this paper, the filtered-X LMS algorithms, the adjoint LMS algorithms, and the robust adjoint LMS algorithms will be introduced for applications in active noise control(ANC). The filtered-X LMS algorithms is currently the most popular method for adapting a filter when the filter exits a transfer function in the error path. The adjoint LMS algorithms, that prefilter the error signals instead of divided reference signals in frequency band, is also used for adaptive filter algorithms to reduce the computational burden of multi-channel ANC systems such as the 3D space. To improve performance of the adjoint LMS ANC system, an off-line measured transfer function is connected parallel to the LMS filter. This parallel-fixed filter acts as a noise controller only when the LMS filter is abnormal condition. The superior performance of the proposed system was compared through simulation with the adjoint LMS ANC system when the adaptive filter is in normal and abnormal condition.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제7권3호
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• pp.198-204
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• 2007

In mobile robotics, ultrasonic sensors became standard devices for collision avoiding. Moreover, their applicability for map building and navigation has exploited in recent years. In this paper, as the preliminary step for developing a multi-purpose autonomous carrier mobile robot to transport trolleys or heavy goods and serve as robotic nursing assistant in hospital wards. The aim of this paper is to present the use of multi-sensor data fusion such as ultrasonic sensor, IR sensor for mobile robot to navigate, and presents an experimental mobile robot designed to operate autonomously within both indoor and outdoor environments. The global map building based on multi-sensor data fusion is applied for recognition an obstacle free path from a starting position to a known goal region, and simultaneously build a map of straight line segment geometric primitives based on the application of the Hough transform from the actual and noisy sonar data. We will give an explanation for the robot system architecture designed and implemented in this study and a short review of existing techniques, Hough transform, since there exist several recent thorough books and review paper on this paper. Experimental results with a real Pioneer DX2 mobile robot will demonstrate the effectiveness of the discussed methods.

• 한국정보통신학회논문지
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• 제12권9호
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• pp.1584-1590
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• 2008

영역 질의와 궤적 질의로 구성된 복합질의는 특정 영역에 위치하는 이동체의 궤적을 검색하는 질의이다. 궤적질의는 선행궤적을 찾기 위해 점질의를 계속 반복하기 때문에 복합질의의 성능을 결정짓는 중요한 요소이다. 이 경우에 점질의는 인덱스의 노드를 중복해서 방문하기 때문에 질의처리의 수행속도가 매우 느려진다. 이 논문은 영역 질의에 우수한 성능을 가진 R-tree 기반의 이동체 색인을 대상으로 궤적 질의를 효율적으로 처리함으로써 복합 질의의 성능을 향상시키기 위한 방법을 제시한다. 기존 연구의 문제점인 노드의 중복 방문을 방지하기 위해 최소 공통 탐색 선분을 정의하여 단일 방향으로만 탐색하며 궤적을 예측하고 예측된 선분을 이용하여 연속된 궤적을 동시에 탐색하는 예측기반 여과 방법을 제안한다.

• 한국군사과학기술학회지
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• 제22권5호
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• pp.616-624
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• 2019

In order to understand flying aircraft, satellite, missile, etc, a telemetry ground system is used to receive, record, and process the transmitted radio signal from vehicles. In some cases, a line-of-sight communication is not possible along to the trajectory of vehicles, and multipath fading result in a shade area of communication. A number of telemetry ground systems are installed to overcome this limitation, and acquire the transmitted signal seamlessly. The telemetry signals received by multiple independent ground systems have independent probability of errors since they experienced their own communication channels. In other words, we can exploit the independent error characteristics of received signals by processing them in a hybrid method. The optimum hybrid post-process method is proposed in this study, and applied to process telemetry signals acquired from flight tests.

• Journal of the Optical Society of Korea
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• 제17권1호
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• pp.103-108
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• 2013

The operation of a Doppler wind LIDAR in a mobile environment is very sensitive to shocks and vibrations, which can cause critical failures such as misalignment of the optical path and damage to optical components. To be able to stabilize the LIDAR and to perform wind field measurements in motion, a shock absorption and vibration isolation system was designed and implemented. The performance of the vehicle-mounted Doppler wind LIDAR was tested in motion, first in a circular test route with a diameter of about 30 m and later in regular expressway traffic. The vibration isolation efficiency of the system was found to be higher than 82% in the main vibration area and shock dynamic deflection was smaller than maximal deflection of the isolator. The stability of the laser locking frequency in the same mobile environment before and after the vibration isolation system installation was also found to be greatly improved. The reliability of the vibration isolation system was confirmed by good results of the analysis of the LIDAR data, in particular the plane position indicator of the line of sight velocity and the wind profile.

• 대한수학회보
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• 제58권5호
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• pp.1279-1300
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• 2021

Let P be a finite point set in ℝ² with the set of distance n-chains defined as ∆_n(P) = {(|p₁ - p₂|, |p₂ - p₃|, …, |p_n - p_n+1|) : p_i ∈ P}. We show that for 2 ⩽ n = O_|P|(1) we have ${\mid}{\Delta}_n(P){\mid}{\gtrsim}{\frac{{\mid}P{\mid}^n}{{\log}^{\frac{13}{2}(n-1)}{\mid}P{\mid}}}$. Our argument uses the energy construction of Elekes and a general version of Rudnev's rich-line bound implicit in [28], which allows one to iterate efficiently on intersecting nested subsets of Guth-Katz lines. Let G is a simple connected graph on m = O(1) vertices with m ⩾ 2. Define the graph-distance set ∆_G(P) as ∆_G(P) = {(|p_i - p_j|)_{i,j}∈E(G) : p_i, p_j ∈ P}. Combining with results of Guth and Katz [17] and Rudnev [28] with the above, if G has a Hamiltonian path we have ${\mid}{\Delta}_G(P){\mid}{\gtrsim}{\frac{{\mid}P{\mid}^{m-1}}{\text{polylog}{\mid}P{\mid}}}$.

• International journal of advanced smart convergence
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• 제8권3호
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• pp.78-86
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• 2019

Recently, IoT researches using sensor data based on embedded networks in various fields including healthcare and sports have been continuously attempted. This study analyzes golf ball mobility to support IoT application in golf sports field. Generally, since the difference in density occurs due to the condition of the inner material and the abnormal state at the time of the outer skin joining during the manufacturing of the golf ball, the weight of each subset is equal for any two points with the same radius in the sphere cannot be guaranteed. For this reason, the deflected weight of the sphere has the undesirable effect of hitting the ball in a direction in which the weight of the ball is heavy. In this study, it is assumed that there is a unique center of gravity of the ball, and even if the golf ball cannot be manufactured perfectly, it wants to establish the basic principle to accurately recognize or mark the putting line based on the center of gravity. In addition, it is evaluated how the mobility of the golf ball with a deviation from the center of gravity of the golf ball affects the progress path (or movement direction) and the moving distance (or carry distance) after the golfer hits. The basic model of the mobility of the golf ball can help the golfer exercise model and the correlation analysis. The basic model of the mobility of the golf ball can help the golfer exercise model and the correlation analysis.

• 한국수정란이식학회지
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• 제33권4호
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• pp.337-342
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• 2018

Cryopreservation is mainly used for preservation of boar sperm. However, this method stresses the sperm by reactive oxygen species (ROS), and the conception rate and the litter size are not more efficient than the liquid preservation of spermatozoa. Therefore, we use chitosan which is a natural product derived antioxidant compound. We used GnHA (chitosan+hyaluronic acid) and GnHG (chitosan hydrogel) as chitosan complexes to cryopreserve boar sperm for improve sperm metabolism and function. Sperm parameter (sperm motility, progressive motility, path velocity, straight-line velocity, curvilinear velocity) is measured by computer-assisted sperm analysis (CASA) using frozen sperm with GnHA or GnHG (0, 0.25, 0.5, 1 mg/mL), respectively. Also, lipid peroxidation analysis using malondialdehyde (MDA) is performed to confirm the antioxidative effect of chitosan in frozen spermatozoa. CASA analysis showed GnHA and GnHG are effective against cryopreserved boar sperm. And antioxidant effect is measured by lipid peroxidation analysis. GnHA and GnHG, which is chitosan complex are effective for boar sperm cryopreservation by antioxidant effect.

• The Journal of Asian Finance, Economics and Business
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• 제8권4호
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• pp.105-112
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• 2021

This study aims to find empirical evidence of the effect of increasing income on the potential transfer of wealth from manufacturing companies that go public to stakeholders. Earnings management with an accrual approach with the Modified Jones model is an identifier of the availability of earnings management practices, without paying attention to both positive and negative symbols. The interpretation of the results of the discretionary accrual measurement between positive and negative symbols has different meanings. Positive discretionary accruals indicate that management uses income-increasing techniques. Meanwhile, negative discretionary accruals indicate that management uses income-reducing techniques. Income-increasing techniques tend to be viewed as opportunistic behavior of managers. This study used 111 data from manufacturing companies listed on the IDX (Indonesia Stock Exchange) from 2015-2018. Path analysis is used to test the hypothesis. The results of this study are in line with the point of view of management strategy, increasing income is used as a way to transfer potential welfare from the company to stakeholders. Social welfare (tax) and managerial remuneration are proven to be mediators in increasing the effect of increasing income on future company value. Further research can complete the potential welfare transfer against the shareholders related to income-increasing strategy.