Earticle

RFID (Radio Frequence Identification) 기술을 이용한 위치 인식은 이차원 평면 또는 삼차원 공간에서 태그의 좌표를 추정하는 기법이 주를 이루고 있으며, 일부 일차원 상의 태그 순서에 대한 연구가 있다. 본 논문에서는 RFID 리더의 움직임을 통해 이차원 배열 형태로 분포된 수동형 태그들의 상대적 위치를 추정하는 기법을 제안한다. 리더의 움직임은 연속된 읽기주기(read cycle) 동안 인식된 태그 집합에 변화를 가져오므로, 본 기법은 이것을 이용하여 태그들 간의 상대적인 위치를 추정하는 것이다. 제안하는 기법은 추가적인 장비를 필요로 하지 않는다. 따라서 RFID 리더 이동을 위한 사용자 인터페이스를 추가함으로써 태그가 부착된 물품의 이차원 순서를 사용하는 다양한 응용에 간단하게 적용될 수 있다.

Localization techniques using RFID technology are mostly estimating the coordinates of tags either in a two dimensional plane or in a three dimensional space. Some previous researches have dealt with sequence estimation of tags spread in one dimension. In this paper, we propose a scheme that estimate the relative position among tags spread in two dimensional array by means of the movement of an RFID reader. Reader movement introduces the changes of tags read in consecutive read cycles, based on which the relative positions among tags are estimated. Proposed scheme does not need additional equipment, and can be easily applied to various applications that use two dimensional relative positions between tagged objects by adding user interface for moving an RFID reader.

PURPOSE: The aim of this study was to investigate the influence of hip abduction velocity and position change on the relative onset times of the gluteus medius, the tensor fascia latae, and the quadratus lumborum in healthy subjects. METHODS: For this study, 15 healthy young adults were recruited. The subjects were asked to move their hip joints up to 35 degrees of abduction at a speed of $70^{\circ}/sec$ and $17.5^{\circ}/sec$ in the supine and side-lying positions. Electromyography data was collected for the gluteus medius, tensor fascia latae, and quadratus lumborum to determine the onset times. RESULTS: There were significant differences between the fast speed ($70^{\circ}/sec$) and the slow speed ($17.5^{\circ}/sec$) in hip abduction in a supine position and in a side-lying position, relatively. The onset time of the gluteus medius was faster than that of the tensor fascia latae and the quadratus lumborum in the side-lying position at the speed of $70^{\circ}/sec$ and $17.5^{\circ}/sec$. CONCLUSION: The findings of this study indicated that hip abduction in a side-lying position is an effective method to recruit the gluteus medius earlier than the tensor fascia latae and the quadratus lumborum. Thus, the exercise position is considered necessory in the purpose of rehabilitation for gluteus medius muscle strengthening program.

It is generally important to get a precise position information for autonomous unmanned vehicle(AUV) to run safely. For getting the position of AUV, the GPS has been using to navigation in a vehicle. Though it is useful to finding a position, it is difficult to precisely control a trajectory of the AUV due to large measuring error which may reach over 10 meters. Therefore to apply AUV it needs to compensate for the error. This paper proposes a method to more precisely localize AUV using three low-cost differential global positioning systems (DGPS). The distance errors between each DGPS are minimized as using the least square method (LSM) and the Kalman filter to eliminate a Gaussian white noise. The selected DGPS is cheaper and easier to set up than the RTK-GPS. It is also more precise than the general GPS. The proposed method can compensate the relatively position error according to stationary and moving distance of the AUV. For evaluating the algorithm by simulation, the DGPS signal with the Gaussian white noise to any points is generated by the AR model and compared with the measurement signal. It is confirmed that the proposed method can effectively compensate the position error as comparing with the measurement signal. The compensated position signal can be used to localize and control the AUV in the road.

본 연구에서는 현존하고 있는 잠금 해제 방식에서 보이는 문제점으로부터 출발해 보안성 및 사용성 측면에서 개선된 블라인드 인터랙션을 적용한 상대적 위치 기반 패턴 잠금 해제 방식을 제안하고 이론적 타당성을 고찰했다. 기존 숫자암호 잠금 해제 방식과 패턴 그리기 잠금 해제 방식과의 차이를 실험을 통해 확인하고 실용적 가치를 평가했다. 상대적 위치 패턴은 숫자 암호 보다 쉽게 기억되고 그리기 패턴과 비슷한 정도의 학습 용이성을 보여 주었고 타 방식에 비해 훔쳐보기 공격에 안전한 결과를 얻었다. 생체신호를 센싱 할 센싱 모듈을 사용할 필요 없이 터치스크린의 기본기능 만으로 실현 가능하기에 적은 원가로 제작할 수 있다. 시각적 요소가 필요 없는 방식이기에 시각 장애인과 같은 특수 사용자들도 불편함 없이 사용할 수 있기에 실용적 가치도 상대적으로 높다.

In this study, we propose a new Relative position pattern unlocking solution based on blind interaction, which is a new unlocking method, and compared it with existing unlocking methods to verify usability and security improvement. And verified the practical value of the proposed new unlocking solution. The relative position pattern unlock method is easily remembered than the numeric code method and is worth practical enough to show a degree of learning ease similar to the drawing pattern method. The new method is safer to steal than other two methods. It can be manufactured at a low cost and can also be used by special users such as blind people. Therefore, the practical value is relatively high.

본 논문은 자유수면에서 마이크로 중력식 와류 수차의 성능에 블레이드 상대위치 변화의 영향을 이해하는 것이다. 일정한 와류 유동에서 자유수면 아래 상대 와류 수심비(y/hv)의 범위 0 ~ 0.778 지점에 설치된 블레이드의 위치 변화에 따른 마이크로 와류 수차의 회전수, 전압 및 전류를 측정하였다. 유량은 0.0063 ~ 0.00662 m3/s 범위이다. 실험 결과는 유입되 는 유속과 난류강도의 분포가 변하기 때문에 블레이드의 상대위치가 마이크로 와류 수차의 성능에 영향을 미치는 것으로 나타났다. 와류 수차에서 발생하는 에너지의 최대량은 상대 와류 수심비 0.111 ~ 0.222 지점에서 발생했다. 상대 와류 수심비 0.111 지점의 출력은 자유수면 아래 상대 와류 수심비 0.588 지점보다 약 2.4배 더 크게 나타난다.

This paper contributed to the understanding of the effect of the blade relative position on performance of micro gravitational vortex turbine in free water surface. In a constant vortex flow, the rotation, voltage and current of micro vortex water turbine were measured according to the position change of the blade installed at the relative vortex height (y/hv) ranging from 0 to 0.778 below the free water surface. The flow rate ranged from 0.0063 to 0.00662 m3/s. The results of the experiments showed that relative positions of the blade affected the performance of vortex water turbine because the distributions of incoming flow velocity and turbulence intensity were changed. The highest amount of the energy generated by the vortex water turbine occurred in the relative vortex height ranging from 0.111 to 0.222. The output power at the relative vortex height of 0.111 was about 2.4 times larger than the relative vortex height of 0.588 below the free water surface.

실내에서의 위치기반 서비스 및 상황인식 서비스를 위해서는 실내에서의 정밀한 위치인식 기술이 필수적이 다. 신호원과 여러 개의 신호 수신기와의 거리 차이를 이용하여 신호원의 상대위치를 추정하는 TDOA(Time Difference of Arrival) 기술이 사용되고 있는데, 거리 차이 측정의 오차에 따른 위치 추정 오차가 발생하므로 이를 최 소화하기 위한 연구가 많이 진행되어 왔다. 본 논문에서는 신호원과의 거리 차이값을 이용하여 계산된 여러 근중에서 실제의 근을 선별하고 이를 평균내어 신호원의 위치를 추정하는 알고리즘이 제안되었으며, 기존의 방법에 비해 오차 가 개선되었다.

For location based service and context awareness services, accurate indoor positioning technology is essential. The TDOA method that uses the range difference between signal source and receivers for estimating the location of the signal source, has estimation error due to measurement error. In this paper, a new algorithm is proposed to select the real root among calculated roots using the range difference information, and the estimated position of the signal source shows good accuracy compared to the existing method.

An integrated coupled control strategy for a servicing spacecraft autonomously approaching and docking with a freely tumbling target is studied. To implement capturing successfully, the docking port of the servicing spacecraft should be always pointing to the docking port of target during close rendezvous and docking, which involves proximity maneuvering of coupled position and attitude simultaneously. The integrated coupled control is accomplished through a robust sliding mode control for coupled relative position and attitude tracking. In order to design the integrated coupled control law, the integrated coupled dynamics of relative position and attitude is established through relative position vector and relative attitude quaternion. Then, based on the integrated coupled dynamics, an integrated coupled control law is designed through a robust sliding mode control technique which is constructed by two sliding surfaces. The convergence of sliding surfaces and tracking error are guaranteed in presence of unknown but bounded disturbances and model uncertainties. The robustness of the proposed control law to measurement noise is also analyzed. Finally, three numerical simulation scenarios are conducted and the results validate the effectiveness and robustness of the integrated coupled control law.

One of key goals of disaster response and relief robots is to acquire knowledge about the situation that would be either dangerous or inaccessible to human operator. However, the robot is difficult to acquire tele-operations from the operator. A disconnected communication link and no-visual control situation are frequently happened in disaster areas. Moreover, disaster scenarios are typically spatially distributed, so we may need an intelligent robot that has functions such as autonomy, cooperation, and collective behaviors. Thus, we propose the bio-inspired modular robot named as ARTHROBOT so as to support emergency responders. ARTHROBOT can assemble or disassemble process based on the proposed mobile algorithms.

This paper proposes a vehicle-positioning improvement algorithm that utilizes positioning data collected from budget GPS devices and vehicle data obtained from ODB devices and relays the information via WAVE communications between cars. Data from both sender and recipient vehicles are matched with Procrustes analysis based on the location in-formation of the other car. The corrected location data is used in order to calculate the distance be-tween the two cars. By using commercial lane-detection technology, the distance between the cars and each lane can also be calculated with the calibrated location data. The difference between the cars’ video-estimated distance and GPS data can be used to improve vehicle-location correction algorithms.

Background: This study aims to measure regional healthcare differences in Korea, and define relatively underserved areas. Methods: We employed position value for relative comparison index (PARC) to measure the healthcare status of 250 areas using 137 indicators in five following domains: healthcare demand, supply, accessibility, service utilization, and outcome. We performed a sensitivity analysis using t-SNE (t-distributed stochastic neighboring embedding). Results: Based on PARC values, 83 areas were defined as relatively underserved areas, 49 of which were categorized as moderate and 34 as severe. The provincial regions with the most underserved areas were Gyeongbuk (16 areas), Gangwon (13), Jeonnam (13), and Gyeongnam (12). Conclusion: This study suggests a relative comparison approach to define relatively underserved areas in healthcare. Further studies incorporating various perspectives and methods are required for policy implications.

Flow of steam is different from other gas flows and involves droplet generation in the flow field. This phase-transition affects not only flow aspects, but also machine performance in a negative way. These days, CFD is widely used in machine design and optimization processes, so phase-transition phenomena in steam flows should be considered in CFD to predict the internal flows precisely. In the past, non-equilibrium wet-steam model was implemented on in house code T-Flow and it was applied to steady calculations of a steam turbine model with changing stator/rotor interface. The results showed that mixing plane method is not appropriate to simulate steam condensing flow and frozen rotor method can be affected by relative position between a stator and a rotor. Therefore, steady wet-steam flows with non-equilibrium phase-transition were simulated for a steam turbine model in this study with 4 different stator-rotor positions and their effects on the wet-steam flow fields were investigated in detail.

Objective: To provide reliable prediction models based on dentoskeletal and soft tissue variables for customizing maxillary incisor positions and to optimize digitalized orthodontic treatment planning. Methods: This study included 244 Chinese women (age, 18-40 years old) with esthetic profiles after orthodontic treatment with fixed appliances (133 in group I: 1° ≤ The angle between the nasion [N]-A point [A] plane and the N-B point [B] plane [ANB] ≤ 4°; 111 in group II: 4° < ANB ≤ 7°). Dental, skeletal, and soft tissue measurements were performed on lateral cephalograms of the participants. Correlation and multiple linear regression analyses were used to determine the influence of dentoskeletal and soft tissue variables on maxillary incisor position. Results: The ideal anteroposterior position of the maxillary incisor varied between sagittal skeletal patterns. The position of the maxillary incisor correlated with the sagittal discrepancy between the maxilla and the mandible (ANB), protrusion of the midface, nasal tip projection, development of the chin, and inclination of both the maxillary and mandibular incisors. Distance from the maxillary central incisor to nasion-pogonion plane predicted using multiple linear regression analysis was accurate and could be a practical measurement in orthodontic treatment planning. Conclusions: Instead of using an average value or norm, orthodontists should customize a patient's ideal maxillary incisor position using dentoskeletal and soft tissue evaluations.

We made a study on real-time determination method for relative position using the laser-measured distance data between satellites. We numerically performed the determination of relative position in accordance with extended Kalman filter algorithm using the vectors obtained through nonlinear equation of relative motion, laser simulator for distance measurement, and attitude determination of chief satellite. Because the spherical parameters of relative distance and direction are used, there occur some changes in precision depending on changes in relative distance when determining the relative position. As a result of simulation, it was possible to determine the relative position with several millimeter-level errors at a distance of 10 km, and sub-millimeter level errors at a distance of 1 km. In addition, we performed the determination of relative position assuming the case that global positioning system data was not received for long hours to see the impact of determination of chief satellite orbit on the determination of relative position. The determination of precise relative position at a long distance carried out in this study can be used for scientific mission using the satellite formation flying.

Purpose: This study examined the factors that can be associated with the appearance of the interproximal papilla. Methods: One hundred and forty-seven healthy interproximal papillae between the maxillary central incisors were examined. For each subject, a digital photograph and periapical radiograph of the interdental embrasure were taken using a 1-mm grid metal piece. The following parameters were recorded: the amount of recession of the interproximal papilla, contact point-bone crest distance, contact point-cemento-enamel junction (CEJ) distance, CEJ-bone crest distance, inter-radicular distance, tooth shape, embrasure space size, interproximal contact area, gingival biotype, papilla height, and papilla tip form. Results: The amount of recession of the interproximal papilla was associated with the following: 1) increase in contact point-bone crest, contact point-CEJ, and CEJ-bone crest distance; 2) increase in the inter-radicular distance; 3) triangular tooth shape; 4) decrease in the interproximal contact area length; 5) increase in the embrasure space size; and 6) flat papilla tip form. On the other hand, the amount of gingival recession was not associated with the gingival biotype or papilla height. In the triangular tooth shape, the contact point-bone crest distance and inter-radicular distance were longer, the interproximal contact area length was shorter, and the embrasure space size was larger. The papilla tip form became flatter with increasing inter-radicular distance and CEJ-bone crest distance. Conclusions: The relative position of the interproximal papilla in healthy subjects was associated with the multiple factors and each factor was related to the others. A triangular tooth shape carries a higher risk of recession of the interproximal papilla because the proximal contact point is positioned more incisally and the bone crest is positioned more apically. This results in an increase in recession of the interproximal papilla and flat papilla tip form.

Previous studies have shown that even native English speakers have difficulty processing and interpreting object-extracted relative clauses compared to subject-extracted relative clauses (Ford, 1983, King & Just, 1991; Gibson, 1998). However, recent studies in English and Korean have shown that for sentences with high syntactic complexity, the relative difficulty of object-extracted relative clauses compared to subject relative clauses may be attenuated or eliminated (Kim, 2009, 2010). This study seeks to isolate the effects of gap position in English relative clauses by examining the comprehension of English relative clauses by Korean L2 learners of English, and also investigate whether these effects are correlated with L2 (English) proficiency. 15 students at a Korean university participated in an offline questionnaire study. The results showed that overall, the participants had lower accuracy scores on the object-extracted relative clauses, as compared to subject-extracted relative clauses (t= 4.70, p< .0001). In addition, the participants that had the lowest accuracy scores on the object-extracted relative clause comprehension questions were the participants with proficiency scores that were below average. These results suggest that the absence of gap effects in earlier studies (Kim, 2009, 2010) was indeed due to high levels of syntactic complexity that exceeded their threshold, and that the relative difficulty due to the position of the gap in the relative clause may be modulated by factors such as sentence complexity and L2 proficiency.

The design principles and implementation of rebar lap splice in architectural structures are governed by building regulations. Nevertheless, the minimization of rebar-cutting waste (RCW) is often impeded by the mandatory requirements pertaining to the rebar lapping zone as prescribed in design codes. In real-world construction scenarios, compliance with these rules often falls short due to hurdles concerning productivity, quality, safety, time, and cost. This discrepancy between code stipulations and on-the-ground construction practices necessitates an academic exploration. The goal of this research was to delve into the effect of rebar lap splice placement on the robustness and constructability of building edifices. The study initially took on a review of the computation of rebar lapping length and the rules revolving around the lapping zone. Following this, a structural robustness and constructability examination was undertaken, focusing on adherence to the lap splice zone. The interpretations and deductions of the research led to the following insights: (1) the efficacy of rebar lap splice is not solely contingent on the moment, and (2) the implementation of rebar lap splice beyond the specified zone can match the structural integrity and robustness of those confined within the designated area. As a result, the constraints on the rebar lapping zone ought to be revisited and possibly relaxed. The conclusions drawn from this research are anticipated to reconcile the disconnect between building codes and practical construction conditions, furnishing invaluable academic substantiation to further the endeavor of achieving near-zero RCW.

선박교통관제사는 충돌위험이 있는 선박을 식별하기 위하여 각 선박의 벡터(코스와 속력)를 실시간으로 모니터링하며, 이때 VTS 시스템을 통하여 CPA(Closest Point of Approach)와 TCPA(Time to Closest Point of Approach)를 확인할 뿐 아니라 선박의 조우상황에 따른 위험도 함께 고려하게 된다. 본 연구는 선박충돌위험을 자선의 관점이 아닌 제 3자 즉, VTS(Vessel Traffic Service)관점에서 서로 충돌 위험이 있는 선박을 실시간으로 계산하는 알고리즘과 시스템을 개발하기 위한 기초연구로써 선박의 조우상황에 따른 위험도를 구하는 것이 목적이다.

VTSO make a decision which one will be danger and what to expect ship's actions due to each encountering situation with CPA(Closest Point of Approach) and TCPA(Time to Closest Point of Approach) by monitoring ship's vectors(Course & Speeds) in real-time through the VTS system. This study is the fundamental research for developing algorithm and system that does not decide the collision risk in one's own ship's viewpoints, but it identifies the related ships into danger through the third party(VTS ) in real time.