Earticle

본 연구의 목적은 전자 퍼포먼스 트래킹 시스템(EPTS)의 GPS, LPS, IMU 센서, 영상추적(VID) 기기를 활용하 여 무용 동작을 정량화하여 과학적인 무용 평가 방법을 모색하며, 무용수의 부상 방지 예측 모델의 적용 가능성을 제시하는 데 있다. 연구 결과는 무용의 객관적인 평가를 위한 척도로 역동성, 연속성, 균형성의 요인을 EPTS의 LPS와 IMU 센서를 활용하여 정량적인 데이터를 측정할 수 있으며, 이를 통해 무용수의 움직임을 비교 및 평가할 수 있다. 또한, 무용수들이 훈련 및 경기에서 측정되는 가속, 감속, 방향전환, 점프 그리고 Playerload의 횟수를 주간 단위로 운동량을 계산하여, 부상 발생률(ACPR)을 확인하고 과 훈련으로 인한 상해를 방지할 수 있다.

The purpose of this study is to investigate the objective and the scientific evaluation method of dance using Electronic Performance Tracking System (EPTS) and to suggest the applicability of predictive model of injury prevention of dancers. The results of this study can be used to measure quantitative data using EPTS's LPS and IMU sensors. Dancers can also be calculated the number of high-strength accelerations, decelerations, Chang of Direction, jumps and playerload measured in training and competitions as momentum per week to check the incidence of injury (ACPR) and prevent injury from over-training.

본 논문에서는 cross-eye의 두 재밍 안테나의 진폭 불일치로 인한 성능 저하를 고려한다. 진폭비의 불일치 는 기계적 결함에 따른 실제 진폭비와 명목상 진폭비의 차이가 정규분포를 갖는 랜덤변수로 모델링한다. 1차 테일러 전개와 2차 테일러 전개를 통한 해석적 성능분석이 제안된다. 실제 진폭비와 명목상 진폭비의 불일치가 발생한 Cross-eye 재밍의 성능 측정은 mean square difference (MSD)를 계산함으로서 측정된다. 해석적으로 유도된 MSD는 1차 테일러 전개 기반 시뮬레이션 기반 MSD 및 2차 테일러 전개 기반 시뮬레이션 기반 MSD와 해석 기반 MSD와 비교함으로써 검증된다. 계산비용이 높은 Monte-Carlo기반 MSD보다 해석 기반 MSD가 우수함을 보인다.

In this paper, performance degradation in the cross-eye jamming due to amplitude mismatch of two jamming antennas is considered. The mismatch of the amplitude ratio is modeled as a random variable with a normal distribution of the difference between the actual amplitude ratio and the nominal amplitude ratio due to mechanical defects. In the proposed analytic performance analysis, the first-order Taylor series expansion and the second-order Taylor series expansion is adopted. Performance measure of the cross-eye jamming is the mean square difference (MSD). The analytically derived MSD is validated by comparing the analytically derived MSD with the first-order Taylor series-based simulation-based MSD and the second-order Taylor series-based simulation-based MSD. It shows that the analysis-based MSD is superior to the Monte-Carlo-based MSD, which has a high calculation cost.

In this paper, code tracking loop was designed and the timing tracking performance of 1st order and 2nd order Delay-Locked Loop(DLL) for S-CDMA cable modem was evaluated in impulse, AWGN, and frequency offset channel environment. The designed 1st order DLL showed insufficient tracking performance in severe impulse noise or large frequency offset. On the other hand, the designed 2nd order DLL of loop gain G1=0.8, G2=0.01 showed good tracking performance with noticeable reduction of jitter.

The tracking trainer is an equipment for practicing every step of firing missile, targeting either a real target or a virtual target with the IR source in the field. The main components of the tracking trainer are the training missile round, dummy BCU, battery pack, and battery charger. The tracking practice missile is equipped with a controller instead of a warhead, and a propulsion and ejection motor. The launcher system for the tracking trainer is the same as the actual launcher system; the size, shape, electronic and mechanical interface are exactly the same as the actual equipment. This paper shows that the previously researched cooled type tracking missile has limitations in its tracking range and is inadequate for repeated practice, especially under unusual environments. This study suggests some improvements in the range of the cooled type tracking missile so that it could be used more repeatedly. The main configurations of Chiron consist of missiles in container, launcher system, tracking trainer, simulator, and mobile maintenance equipment. In this paper, we adopt an un-cooled type seeker for the tracking trainer so that it does not require nitrogen gas injection for operation. As the consequence, the system has become very cost effective. The controller which shows the status of tracking training is also designed to be integrated into the missile for more convenient operation.

The efficiency a solar cell system us mainly affected by the solar incident angle on the photovoltaic panels. The purpose of this thesis is to investigate a solar light-tracking BIPV system as the applicability on the educational facilities. Two typical types of BIPV system by operating system; fix PV panel type and rotating PV panel type, are analyzed in the performance of electric power generation and compared with solar light-tracking BIPV system. The simulation of solar irradiance is performed using ECOTECT, which has various advantage such as easy user interface and simple simulation processes. In order to evaluate the electric power generation efficiency, the electric power generation rate and global irradiation were measured on the spring/autumn equinox and the summer/winter solstice. As a result, the generation of solar power by solar light-tracking BIPV system shows 6.7% higher than fix-PV panel system. Meanwhile the generation of solar power by rotating PV system shows 1% higher than fix-PV panel system. Therefore, the solar light-tracking BIPV system will be an effective solution to develop for the zero energy building in educational facility.

본 연구는 야구에서 타자의 타격 성과를 예측하기 위한 배트 트래킹 지표와 기존 타격 지표 간의 상관관계를 비선형 회귀분석을 통해 분석하고 해석하는 데 중점을 두었다. MLB Statcast가 제공한 데이터를 바탕으로 평균 배트 스피드, 정타율, 블래스트, 스윙 길이와 타자의 주요 성과 지표인 안타 수, 홈런 수, 타율, 장타율, OPS 간의 관계를 분석하였다. 분석 결과, 정타율은 안타 수에 대해 양의 영향을 미쳤으며, 블래스트는 안타 수와 장타율에 큰 음의 영향을 미쳤다. 특히 홈런 수와 OPS의 경우, 블래스트와 정타율 간의 상호작용이 매우 중요했으며, 이들의 결합은 홈런 수와 OPS에 각각 긍정적인 영향을 나타냈다. 본 연구는 배트 트래킹 지표와 타격 지표 간의 복잡한 상호작용을 명확히 이해 함으로써, 타자의 타격 성과를 보다 정확하게 예측하는 데 중요한 통찰을 제공하며, 이는 야구 분석 및 선수 평가에 실질적인 기여가 가능할 것이다. 또한, 이러한 분석을 통해 배트 트래킹 데이터가 기존 타격 지표와 어떻게 상호작용하 는지를 심층적으로 이해하는 데 중요한 기초 자료를 제공하고, 야구 선수의 평가에 새로운 시각을 제시할 수 있다.

This study focuses on analyzing and interpreting the relationship between Bat Tracking metrics and traditional hitting metrics using non-linear regression analysis to predict baseball batter performance. Based on data provided by MLB Statcast, we analyzed the relationships between Average Bat Speed, Squared-up Rate, Blast, Swing Length, and key performance indicators such as Hits, Home Runs, Batting Average, Slugging Percentage, and OPS. The analysis revealed that Squared-up Rate had a significant positive impact on Hits, while Blast showed a substantial negative impact on both Hits and Slugging Percentage. In the case of Home Runs and OPS, the interaction between Blast and Squared-up Rate was crucial, showing positive effects. This study provides important insights into understanding the complex interactions between Bat Tracking metrics and hitting metrics to more accurately predict batter performance, offering practical contributions to baseball analytics and player evaluation.

본 논문에서는 동시통화에 강인한 특성을 갖는 알고리즘의 추적성능을 개선시킬 수 있는 새로운 방법을 제안하였다. 반향경로의 변화를 검출하는 방법과 적응필터의 계수 적응식을 변경하는 방법을 제안하였다. 오차신호 대 스케일 파라메터의 비는 반향경로가 변화한 경우와 동시통화가 발생한 경우에 지속시간이 다른 특성을 가지며 이를 이용하여 반향경로 변화를 검출한다. 제안한 적응필터계수 적응식은 잘못된 오차신호선택을 방지하도록 하여 추적 성능을 개선시킨다. 실제 음성신호와 ITU-T G.168에서 제공하는 반향경로를 사용한 실험을 통하여 제안한 방법이 기존의 방법에 비해 4dB 이상 성능을 개선시킴을 확인하였다.

We present a new algorithm which can improve the tracking performance of the double-talk robust algorithm. A detection method of the echo path change and a modification method for the update equation of the conventional adaptive filter are proposed. A duration of the high error signal to scale parameter ratio varies according to the call status and this property is used to detect the echo path change. The proposed update equation of the adaptive filter improves the tracking performance by prohibiting wrong selection of the error signal. Simulations using real speech signals and echo paths of the ITU-T G.168 standard confirmed that as compared to the conventional algorithm, the proposed algorithm improved the tracking performance by more than 4 dB.

Chip Tracking Loop (CTL) is the key to ensure the accuracy of regenerative pseudo-noise ranging in the deep space measurement and control communication system. However, due to the impact of the code imbalance, clock attenuation rate and noise, the loop locking time of CTL is prolonged and the ranging accuracy is degraded. In this paper, we proposed the discriminator optimization algorithm to address this problem. This algorithm is based on the loop discrimination performance of clock code and composite code, and the impact of the noise on the discrimination performance. In order to improve the tracking accuracy and shorten the loop locking time, this algorithm corrected the curve of discriminator’s gain by compensating discriminator’s gain. Both the theory analysis and simulation results illustrate that the algorithm can correct the discriminator’s gain curve, reduce the loop locking time and ensure the significant tracking accuracy in low SNR.

Augmented reality (AR), which integrates virtual media into reality, is increasingly utilized across various industrial sectors, thanks to advancements in 3D graphics and mobile device technologies. The IT industry is thus carrying out active R&D activities about AR platforms. Google plays a significant role in the AR landscape, with a focus on ARCore services. An essential aspect of ARCore is the use of anchors, which serve as reference points that help maintain the position and orientation of virtual objects within the physical environment. However, if the accuracy of anchor positioning is suboptimal when running AR content, it can significantly diminish the user's immersive experience. We are to assess the performance of these anchors in this study. To conduct the performance evaluation, virtual 3D objects, matching the shape and size of real-world objects, we strategically positioned ourselves to overlap with their physical counterparts. Images of both real and virtual objects were captured from five distinct camera trajectories, and ARCore's performance was analyzed by examining the difference between these captured images.

Sensors collect information for Internet of Things (IoT)-based services. However, indoor construction sites have a poor communication environment and many interfering elements that make it difficult to collect sensor information. In this study, a network was constructed between a Bluetooth Low Energy (BLE)-based IoT device based on a serverless IoT framework and a router. This experimental environment was applied to large- and small-scale indoor construction sites. Experiments were performed to test the communication performance of BLE-based IoT devices and routers at indoor construction sites. An analysis of the received signal strength indication (RSSI) graph patterns collected from the communication between the BLE-based IoT devices and routers for different testbed site situation revealed areas with good communication performance and poor communication performance due to interfering factors. The results confirmed that structural components of the building as well as the materials, equipment, and temporary facilities used in indoor construction interfere with the communication performance. Construction project managers will require improved technical knowledge of IoT, such as optimizing the router placement and matching communication between the router and workers, to improve the communication performance for large-scale indoor construction.

기동 플랫폼에 탑재된 레이다는 플랫폼이 이동 및 회전함에 따라 레이다의 좌표계 상태도 같이 변화한다. 이 때, 추적을 수행하기 위하여 센서로부터 측정된 플랫폼의 상태 정보를 이용하여 표적의 좌표를 변환하게 되며 센서의 잡음, 통신 지연, 센서 갱신 주기와 같은 원인으로 인하여 추적 성능이 저하될 수 있다. 본 논문에서는 센서의 오차로 인한 추적 성능 저하를 최소화하기 위하여 기동 플랫폼의 상태정보를 추정하기 위한 항법 필터를 설계하고 모의 시험을 통해 항법 필터 적용을 통한 추적 성능 개선 효과를 분석하였다. 이러한 항법 필터 설계를 위하여 3가지의 필터 알고리 즘을 분석 및 적용하여 각 필터별 플랫폼 위치 및 자세 성능 개선 효과를 확인하였고 가장 높은 성능의 필터 알고리즘을 적용하여 설계된 항법 필터를 추적 모의 시험에 적용하여 항법 필터 적용 전후의 추적 성능 개선을 확인하였다.

As the radar mounted on a moving platform moves and rotates, the state of the radar's coordinate system also changes. At this time, in order to track target, the target's coordinates should be converted using the platform state measured from the sensor, and tracking performance may deteriorate due to causes such as sensor noise, communication delay, and sensor update cycle. In this paper, to minimize the degradation of tracking performance because of sensor error, we designed a navigation filter to estimate the state of the moving platform and analyzed the effect of improving tracking performance by applying the navigation filter through a simulation test. To design this navigation filter, three filter algorithms were applied and analyzed to confirm the effect of improving platform position and attitude performance for each filter, and the navigation filter designed by applying the highest performance filter algorithm was applied to a tracking simulation test. Finally we confirmed Improvement in tracking performance before and after applying navigation filters.

무선주파수를 사용하는 추적안테나의 추적성능은 비행체 추적 및 위치 측정에서 매우 중요한 요소이나, 전기적·물리적으로 매우 큰 안테나의 특성을 정확히 측정하는 것은 쉽지 않다. 특히 우주응용분야에서 사용되는 대형 접시형 추적안테나 시스템과 같이 신호원을 따라 안테나의 지향방향이 변하는 경우에는 안테나 지향방향에 따라 특성이 일정하지 않을 수 있다. 본 논문에서는 대형 추적안테나 시스템의 추적 성능지표인 지향정확도 및 추적정확도에 영향을 주는 오차요인을 검토하고, 나로우주센터에서 원격측정용으로 사용하고 있는 11m 대형 접시형 추적안테나에 대한 추적성능을 효율적으로 측정할 수 있는 저궤도위성(Low Earth Orbit)을 사용한 측정방법 및 그 결과를 기술한다.

The tracking performance of the big tracking antenna system using Radio Frequency is very important for the tracking and position measuring for the flight vehicle, but the precise measuring of the tracking performance is not easy, especially for the big antenna system such as ground telemetry antenna or tracking radar in space application because it's characteristics could be different in accordance with the antenna direction. In this paper, the error factors impacting on the tracking performance (pointing accuracy and tracking accuracy) and the ranges of each factor are reviewed, and the simple and efficient method to measure the tracking performance is introduced which using low earth orbit as the signal source. Finally, the measurement results for the telemetry ground antenna in NARO Space Center are reviewed.

영상처리에서 인식에 관련된 기술들은 환경에 아주 많은 영향을 받게 되는데 이러한 인식률을 결정짓는 요 소 중인 파라미터는 환경에 적절한 값을 얼마나 잘 선택하느냐에 따라서 인식률의 큰 차이를 보인다. 본 논문은 눈동 자 추적 알고리즘이 사람이나 실험 환경의 변화에 따라 인식률이 저하되는 현상을 보완하기 위한 성능 향상 및 환경 에 적응하는 시스템의 구현에 대한 방법이다. 최적의 파라미터를 얻기 위해 전 처리에 사용되는 이진화 알고리즘의 문턱값을 학습이 필요한 시기를 적절히 판단해 강화학습을 이용하여 다시 학습시켜 인식률을 향상시키는 방법을 사 용했다. 실험데이터를 수집하기 위해 입력 장치는 가격이 저렴하고 일반적인 웹 카메라를 사용 하였으며 얼굴 영역에 해당하는 많은 양의 이미지를 수집하여 강화학습의 적응력을 실험하였다. 이미지의 그룹을 다양하게 변화시켜 실험한 결과 강화학습을 사용한 경우 그렇지 않은 경우에 비해 작게는 3% 많게는 14%가량의 성능이 향상됨을 확인하였다. 이렇게 성능이 향상된 눈동자 추적 시스템은 휴먼 컴퓨터 인터랙션 분야에 효과적으로 활용될 수 있을 것이다.

Recognition and image processing technology depends on illumination variation. One of the most important factors is the parameters of algorithms. When it comes to select these values, the system has different types of recognition accuracy. In this paper, we propose performance improvement of the eye tracking system that depends on some environments such as, people, location, and illumination. Optimized threshold parameter was decided by using reinforcement learning. When the system accuracy goes down, reinforcement learning used to train the value of parameters. According to the experimental results, the performance of eye tracking system can be improved from 3% to 14% by using reinforcement learning. The improved eye tracking system can be effectively used for human-computer interaction.