Earticle

Many people are exposed to accidents by vehicles or sports. The most frequent injuries by these accidents is concerned with a knee joint. The three-dimensional surface model of a knee is needed for dynamic analysis of knee motion and knee reconstruction. three-dimensional motion data of a knee joint were obtained using X-ray and precise magnetic sensors. The surface data of a femur and a tibia were obtained using cross-sectional pictures by CT. The three-dimensional surface models of a femur and a tibia were made by the method of optimal triangular patch. Using obtained motion data, we simulated the motion of three-dimensional knee joint model.

인지무선네트워크에서 기 사용자(primary user)의 위치를 정확하게 파악하는 것은 2차 사용자(secondary user) 들의 스펙트럼 이용 효율 향상 및 적절한 전력제어를 통한 기 사용자에 대한 간섭을 야기하는 것을 회피하는데 사용 될 수 있기 때문에 인지무선네트워크에서 매우 중요한 연구 주제이다. 노드의 위치를 추정하는 다양한 기법들 중, 수 신신호세기(RSS) 기반의 위치 추정 기법은 추가적인 하드웨어 자원 없이 쉽게 구현할 수 있어 일반적으로 가장 많이 사용되는 기법으로 인지무선네트워크에서도 사용될 수 있다. 하지만, 수신신호세기 기반의 위치 추정에서 노드간 거 리 측정은 수신된 신호 세기를 기반으로 이루어져 무선 채널 환경의 페이딩, 쉐도잉 그리고 장애물 등으로 인해서 거 리 추정의 오차가 생긴다. 따라서 본 논문에서는 수신신호세기 기반으로 기 사용자의 위치 측정의 정확도를 향상시키 기 위하여 전송 손실 지수(path loss exponent) 추정기반의 기 사용자 위치 검출 기법을 제안한다. 시뮬레이션 결과를 통해 제안된 방식이 기존 방식보다 기 사용자 위치 측정의 오차를 줄어 기 사용자에 대한 간섭률을 더 줄일 수 있음 을 보였다.

In cognitive radio networks, acquirement of position information of primary user is very important to secondary network since localization information of primary users can be utilized for improving the spectrum efficiency of secondary network and for avoiding harmful interference to primary users by using proper power control. Among various location methods, Received Signal Strength (RSS)-based localization has been widely used for distance measurements in the location detection process despite its inherent inaccuracy because it can be easily implemented without any additional hardware cost. In the RSS-based localization, the distance is measured by the received signal strength, and distance error can be caused by many factors such as fading, shadowing and obstacle between two nodes. In the paper, therefore we propose a localization scheme based on estimation of path-loss exponent to localize the location of primary users more accurately. Through simulations, it is shown that the proposed scheme can provide less localization error and interference rate to primary users than other schemes.

Triangulation Measurement Method (TCMM) technology, which uses load cells to measure an object's weight or force, continues to advance. Load cell technology is developed for high precision and sensitivity, and is used for extremely precise measurements in the development of nano and micro sensors. Systems employing Triangulation Measurement Method (TCMM) collect electrical signals from load cells to measure vertical load changes resulting from shifts in an object's center of gravity, thereby obtaining load variations over time. The minute shaking of an object reflects slight sway or balance movement as vibration. The signal amplification section in the load cell integrates the steady signal through a specific process before passing it to the microprocessor. The transmissible signal is configured for real-time data transmission and remote monitoring via a smart load cell with an embedded wireless communication module. Changes in the human body are measured as mechanical motion, generating vibrations within a frequency range of 1 to 20 Hz. The results of the Triangular Configuration Measuring Method System (TCMMS) showed motion state changes due to vibration. The wobble motion state of the TCMMS-FA-τMAX was 26.03±5.53 units from the sprinkling monochrome-dot echo, while the wobble motion state of the TCMMS-CO-τMAX was 12.13±2.19 units, the wobble motion state of the TCMMS-FL-τMAX was 4.18±0.74 units, and the wobble motion state of the TCMMS-VI-τMAX was (0.74±0.11) units. We can utilize load cells designed using this Triangular Configuration Measuring Method (TCMM) for precision medical devices, advanced industrial measuring instruments, and more. Load cells can be employed to measure forces such as tension, compression, pressure, or torque, and can serve as indicators for monitoring cardiac activity, similar to an electrocardiogram.

Fingerprint recognition systems are the top topics of biometric research and more researchers’ effort is provided to improve high accuracy and speed. Matching methods based on the minutiae points are commonly used and are effective in practice. Algorithms which based on minutia triplets among them are attractive matchers. However, recognizing fingerprints in poor quality images, direction changed, size different fingerprints and so forth is still a very complex job. To overcome these drawbacks, a fingerprint match method used minutiae-based triangular acreage is described here to improve matching accuracy.

In order to deal with the issue of network attacks and enhance the security of the network environment, intrusion detection is gaining more and more attention all over the world. In this paper, a novel intrusion detection method based on improved triangular matrix factorization is presented. As a type of famous mathematical tool, triangular matrix factorization has a good ability to reduce the large amount of high dimensional data. However, the traditional triangular matrix factorization has its inherent drawbacks such as the difficulty of setting the parameter adaptively, so the model of an improved version of triangular matrix factorization together with its concrete algorithm is proposed in this paper firstly. Then, improved triangular matrix factorization is employed to convert the high dimensional data of the network into low dimensional vectors of several matrices, with which the anomaly detection can be realized. Experimental results indicate that the proposed method is promising, and it does significantly enhance the detection accuracy and computational efficiency compared with other current popular ones.

Products are often evaluated on rating scales to measure and quantify their attributes of interest. In case that one wishes to compare multiple rating datasets simultaneously, there must be a standardized scale with which one can discriminate relative differences among corresponding scale means. In this regard, the concept of Thurstonian modeling applied to various discrimination tests including the triangular method has been recently being reconsidered. In this paper we extend previous researches on the triangular method and evaluate the effect of unequal variances and correlated variables upon the probability of correct response using Monte-Carlo simulation. We observed that the probability of correct response depends on dimensionality, variances, and correlation structure of stimulus sets. But it does not depend on the relative orientation in a multidimensional space.

Recently, a technique for acquiring spatial information data using UAV (Unmanned Aerial Vehicle) has been greatly developed. It is a very crucial issue of the GIS (Geographic Information System) mapping system that passes way point in the unmanned airframe and finally measures the accurate image and stable localization to the desired destination. Though positioning using DGPS (Differential Global Navigation System) or RTK-GPS (Real Time Kinematic-GPS) guarantee highly accurate, they are more expensive than the construction of a single positioning system using a single GPS. In the case of a low-priced single GPS system, the stability of the positioning data deteriorates. Therefore, it is necessary to supplement the uncertainty of the absolute position data of the UAV and to improve the accuracy of the current position data economically in the operating state of the UAV. The aim of this study was to present an algorithm enhancing the stability of position data in a single GPS mode of UAV with multiple GPS. First, the arrangement of multiple GPS receivers through the center of gravity of the UAV were examined. Next, MD (Mahalanobis Distance) is applied to detect instantaneous errors of GPS data in advance and eliminate outliers to increase the accuracy of previously collected multiple GPS data. Processing procedure for multiple GPS reception data by applying the center of the triangular method were presented to improve the position accuracy. Second, UAV navigation systems integrated multiple GPS through configuration of the UAV specifications were implemented. Using the unmanned airframe equipped with multiple GPS receivers, GPS data is measured with the TCM (Triangular Center Method). In addition, UAV equipped with multiple GPS were operated in study area and locational accuracy of multiple GPS of UAV with VRS (Virtual Reference Station) GNSS surveying were compared. The result showed that the error factors are compensated, and the error range are reduced, resulting in the reliability of the corrected value. In conclusion, the result in this paper is expected to realize high-precision position estimation at low cost in UAV using multiple low-cost GPS receivers.

Simultaneous optimization of trusses which concurrently takes into account design variables related to the size, shape and topology of the structure is recognized as highly complex optimization problems. In this class of optimization problems, it is possible to encounter several unstable mechanisms throughout the solution process. However, to obtain a feasible solution, these unstable mechanisms somehow should be rejected from the set of candidate solutions. This study proposes triangular unit based method (TUBM) instead of ground structure method, which is conventionally used in the topology optimization, to decrease the complexity of search space of simultaneous optimization of the planar truss structures. TUBM considers stability of the triangular units for 2 dimensional truss systems. In addition, integrated particle swarm optimizer (iPSO) strengthened with robust technique so called improved fly-back mechanism is employed as the optimizer tool to obtain the solution for these class of problems. The results obtained in this study show the applicability and efficiency of the TUBM combined with iPSO for the simultaneous optimization of planar truss structures.

A preconditioning algorithm is developed in this paper for the iterative solution of the linear system of equations resulting from the p-version boundary element approximation of the three dimensional integral equation with hypersingular operators. The preconditioner is derived by first making the nodal and side basis functions locally orthogonal to the element internal bases, and then by decoupling the nodal and side bases from the internal bases. Its implementation consists of solving a global problem on the wire-basket and a series of local problems defined on a single element. Moreover, the condition number of the preconditioned system is shown to be of order $O((1＋ln/p)^{7})$. This technique can be applied to discretization with triangular elements and with general basis functions.

In this paper, a new modular design technique for globally and practically adaptive output tracking of high-order lower-triangular nonlinear systems is proposed. This technique is not based on certainty equivalence principle and completely uses feedback domination method for these linearly parameterized systems. Contrary to the methods based on adding a power integrator technique, for adaptive control of high-order lower-triangular nonlinear systems, in which the choice of a parameter update law is limited to a Lyapunov-type algorithm, the present method does not have this restriction and uses the swapping identifier as its parameter update law. The modularity of designing the controller and the identifier in this method, which relies on control design using feedback domination approach, is completely different from modular design in Immersion and invariance (I&I) based method, which relies on identifier design and desired features of parameter identification. Finally an example illustrates the feasibility and efficiency of the proposed method.

We synthesized and analyzed the optical transfer function(OTF) of the modified triangular interferometer (MTI) using two-pupil synthesis method. Also, we presented the optimal MTI, which can obtain any bipolar function by combining two wave plates and a linear polarizer. By using the proposed MTI, we can obtain the complex hologram without bias and conjugate image.

프랙탈 이론은 컴퓨터 과학, 공학, 의학, 기상학 등 여러 분야에서 직면하는 복잡하고 불규칙적인 자연현상을 모델링할 수 있는 효과적인 도구로서 인정받아 왔다. 본 연구에서는 지형 및 이미지의 프랙탈 정보 추출에 많이 이용되는 삼각프리즘법의 정밀도를 개선하는 문제를 다룬다. 이를 위해 기존의 샘플링 방법들을 분석하고 그들의 장점을 취하는 새로운 샘플링 방법을 제안한다. 가상의 프랙탈 맵에서 제안된 방법을 다른 방법과 비교하며 그 유효성을 검정한다.

Fractal theory has been adopted as an effective tool for modelling complex and irregular natural phenomena facing in the fields of Computer Science, Engineering, Medical, Climatology and so on. In this paper, we presents an algorithm which enhances the performance of the triangular prism method(TPM) which has been widely used for fractal dimension extraction of natural terrains and images. For this, existing sampling methods are analyzed and a new sampling method which takes their merits is proposed. The effectiveness of the proposed algorithm is tested on fractal terrain maps and its performance is compared with that of other methods.

우리나라의 악취배출 허용기준에는 직접관능법, 공기희석관능법 및 기기분석법에 의한 측정과 규제 기준을 제시하고 있다. 직접관능법의 경우 신속하고 간편하여 현장에서 바로 판정을 내릴 수 있다는 점에서 부지경계선상에서의 악취의 평가수단으로 이용되어 현재까지 많은 평가서에 측정결과를 제시하고 있다. 그러나 직접관능법에 의한 평가결과가 규제치를 넘어 법적 조치가 이루어진 사업장은 거의 없는 듯하다. (중략)

본 논문에서는 삼각형 태양돛의 주름저감설계 방안에 대한 연구를 수행하였다. 태양돛 멤브레인에 부분적으로 발생하는 주름으로 인하여 구조물의 추력성능과 제어성능에 영향을 받을 수 있으므로 멤브레인에 발생하는 주름을 감소시키거나 제거하는 것은 매우 중요하다. 주름을 저감하는 방법으로 태양돛 멤브레인과 붐을 연결하는 케이블의 하중의 각도를 조정하는 방식, 현수선 방식 및 현수선-와이어 방식을 고려하였으며 매개변수 연구를 통하여 주름저감효과에 대해 체계적으로 조사하였다.

In this paper, wrinkle reduction design was studied for triangular sail. Wrinkles in the solar sail membrane can change the load path and surface topology which may have an adverse effect on propulsion performance and controllability. In this study, wrinkle reduction strategies of adjusting cable angle, catenary and catenary-wire schemes were considered and the design parameters for wrinkle reduction were systematically investigated.

중력탐사 자료 처리 과정 중 더 정밀한 지형보정을 수행하기 위하여 삼각요소법(triangular element method)을 이용한 지형보정의 효과를 검증하였다. 삼각요소법은 임의 다면체를 삼각형 면들의 조합으로 구성하여 중력 효과를 계산하는 방법이다. 이 방법을 이용하면 기존 지형 보정에서 사용하는 사각 기둥의 조합으로 지형을 구성하는 것보다 지형을 실제에 가깝게 근사할 수 있으므로 정밀한 지형효과 계산이 가능하다. 이 연구에서는 해석해가 존재하는 원뿔모델을 이용하여 삼각요소법을 이용한 지형보정효과를 검증하였다. 또한 지금까지 많이 사용되어 왔던 사각프리즘법과의 차이를 보이기 위해 지형효과 차이가 많이 발생하는 경사모델에서 두 방법의 차이를 보였다. 이 연구에서 제안한 삼각요소법을 이용한 지형보정 프로그램을 우리나라 남해안의 중력자료에 적용하여 그 효용성을 검증하였다.

We developed a precise terrain correction program using triangular element method (TEM) for microgravity data processing. TEM calculates gravity attraction of arbitrary polyhedra whose surface is patched by triangles. We showed that TEM can calculate more precise terrain effect than conventional rectangular prism method. We tested the accuracy of TEM on the cone model which has analytic solution. Also, we tested the accuracy of TEM on the slope model, this results showed that there are big differences calculated by TEM and rectangular prsim method (RPM) on slope model. The developed terrain correction program was applied on the gravity data on the southern area near sea shore of Korean peninsula, calculated terrain effect very precisely.

This paper presents the matching algorithm with the satellite images using the image warping method. Two stereo images, which are used for the DEM(Digital Elevation Model) extraction, are generally distorted because the images are acquired at different locations and angles. Therefore, the matching Process can't be executed with the original images. To solve this problem, a dynamic triangular image warping method is proposed. At first, the initial matching is executed with seed point, and then, using the matched points from the initial matching, the distorted images is compensated. We experimented this algorithm with the parts of the $6000{\times}6000$ SPOT satellite images. The experiment results show this algorithm is superior to other warping algorithm.