• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권3호
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• pp.1189-1204
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• 2018

Detecting and capturing 3D human structures from the intensity-based image sequences is an inherently arguable problem, which attracted attention of several researchers especially in real-time activity recognition (Real-AR). These Real-AR systems have been significantly enhanced by using depth intensity sensors that gives maximum information, in spite of the fact that conventional Real-AR systems are using RGB video sensors. This study proposed a depth-based routine-logging Real-AR system to identify the daily human activity routines and to make these surroundings an intelligent living space. Our real-time routine-logging Real-AR system is categorized into two categories. The data collection with the use of a depth camera, feature extraction based on joint information and training/recognition of each activity. In-addition, the recognition mechanism locates, and pinpoints the learned activities and induces routine-logs. The evaluation applied on the depth datasets (self-annotated and MSRAction3D datasets) demonstrated that proposed system can achieve better recognition rates and robust as compare to state-of-the-art methods. Our Real-AR should be feasibly accessible and permanently used in behavior monitoring applications, humanoid-robot systems and e-medical therapy systems.

• Structural Engineering and Mechanics
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• 제67권1호
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• pp.33-43
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• 2018

The dynamic output-feedback robust control method based on linear matrix inequality (LMI) method is presented for suppressing vibration response of a functionally graded material (FGM) beam with piezoelectric actuator/sensor layers in this paper. Based on the reduced model obtained by using direct mode truncation, the linear fractional state space representation of a piezoelectric FGM beam with material properties varying through the thickness is developed by considering both the inherent uncertainties in constitution material properties as well as material distribution and the model error due to mode truncation. The dynamic output-feedback robust H-infinity control law is implemented to suppress the vibration response of the piezoelectric FGM beam and the LMI method is utilized to convert control problem into convex optimization problem for efficient computation. In numerical studies, the flexural vibration control of a cantilever piezoelectric FGM beam is considered to investigate the accuracy and efficiency of the proposed control method. Compared with the efficient linear quadratic regulator (LQR) widely employed in literatures, the proposed robust control method requires less control voltage applied to the piezoelectric actuator in the case of same control performance for the controlled closed-loop system.

• 한국정보과학회논문지:소프트웨어및응용
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• 제34권8호
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• pp.743-751
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• 2007

하드웨어 검증에서 성공적으로 적용되었던 모델 검증 기법을 소프트웨어 검증에 활용하는 연구가 활발하다. 이러한 연구 중의 하나가 바운디드 모델 검증이다. 바운디드 모델 검증에서는 모델이 갖는 상태 공간을 한꺼번에 모두 탐색하기보다는 모델의 탐색 범위를 점진적으로 넓혀가면서 에러를 찾는다. 본 논문에서는 이러한 바운디드 모델 검증을 이용하여 BOGOR의 입력 언어인 BIR를 검증하였다. 그 결과 BOGOR에서 제공되는 명시적 모델 검증 기능 보다 우수한 성능을 보였다. 본 논문에서는 BIR 언어를 CNF 논리식으로 변환하는 방법과 단계적 절차를 기술한다.

• Smart Structures and Systems
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• 제14권2호
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• pp.191-207
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• 2014

In this research, an internal model based method is proposed to estimate the structural displacements and velocities under ambient excitation using only acceleration measurements. The structural response is assumed to be within the linear range. The excitation is assumed to be with zero mean and relatively broad bandwidth such that at least one of the fundamental modes of the structure is excited and dominates in the response. Using the structural modal parameters and partial knowledge of the bandwidth of the excitation, the internal models of the structure and the excitation can be respectively established, which can be used to form an autonomous state-space representation of the system. It is shown that structural displacements, velocities, and accelerations are the states of such a system, and it is fully observable when the measured output contains structural accelerations only. Reliable estimates of structural displacements and velocities are obtained using the standard Kalman filtering technique. The effectiveness and robustness of the proposed method has been demonstrated and evaluated via numerical simulations on an eight-story lumped mass model and experimental data of a three-story frame excited by the ground accelerations of actual earthquake records.

• Journal of Power Electronics
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• 제13권3호
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• pp.419-428
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• 2013

The modular multilevel cascade converter (MMCC) is a new family of multilevel power converters with modular realization and a cascaded pattern for submodules. The MMCC family can be classified by basic configurations and submodule types. One member of this family, the Hexverter, is configured as Double-Delta Full-Bridge (DDFB). It is a novel multilevel AC/AC converter with direct power conversion and comparatively fewer required components. It is appropriate for connecting two three-phase systems with different frequencies and driving an AC motor directly from a utility grid. This paper presents the dq model of a Hexverter with both of its AC systems by state-space representation, which then simplifies the continuous time-varying model into a periodic discrete time-invariant one. Then a generalized multivariable optimal control strategy for regulating the Hexverter's independent currents is developed. The resulting control structure can be adapted to other MMCCs and is flexible enough to include other control criterion while guaranteeing the original controller performance. The modeling method and control design are verified by simulation results.

• Journal of Positioning, Navigation, and Timing
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• 제11권4호
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• pp.251-261
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• 2022

The Centimeter Level Augmentation Service (CLAS) is the Precise Point Positioning (PPP) - Real Time Kinematic (RTK) correction service utilizing the Quasi-Zenith Satellite System (QZSS) L6 (1278.65 MHz) signal to broadcast the Global Navigation Satellite System (GNSS) error corrections. Compact State-Space Representation (CSSR) corrections for mitigating GNSS measurement error sources such as satellite orbit, clock, code and phase biases, tropospheric error, ionospheric error are estimated from the ground segment of QZSS CLAS using the code and carrier-phase measurements collected in the Japan's GNSS Earth Observation Network (GEONET). Since the CLAS service begun on November 1, 2018, users with dedicated receivers can perform cm-level precise positioning using CSSR corrections. In this paper, CLAS-based VRS-RTK performance evaluation was performed using Global Positioning System (GPS) observables collected from the refence station, TSK2, located in Japan. As a result of performing GPS-only RTK positioning using the open-source software CLASLIB and RTKLIB, it took about 15 minutes to resolve the carrier-phase ambiguities, and the RTK fix rate was only about 41%. Also, the Root Mean Squares (RMS) values of position errors (fixed only) are about 4cm horizontally and 7 cm vertically.

• Journal of Positioning, Navigation, and Timing
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• 제10권2호
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• pp.75-82
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• 2021

Fields of high-precision positioning applications are growing fast across the mass market worldwide. Accordingly, the industry is focusing on developing methods of applying State-Space Representation (SSR) corrections on low-cost GNSS receivers. Among SSR correction types, this paper analyzes Safe Position Augmentation for Real Time Navigation (SPARTN) messages being offered by the SAfe and Precise CORrection DAta (SAPCORDA) company and validates positioning algorithms based on them. The first part of this paper introduces the SPARTN format in detail. Then, procedures on how to apply Basic-Precision Atmosphere Correction (BPAC) and High-Precision Atmosphere Correction (HPAC) messages are described. BPAC and HPAC messages are used for correcting satellite clock errors, satellite orbit errors, satellite signal biases and also ionospheric and tropospheric delays. Accuracies of positioning algorithms utilizing SPARTN messages were validated with two types of positioning strategies: Code-PPP using GPS pseudorange measurements and PPP-RTK including carrier phase measurements. In these performance checkups, only single-frequency measurements have been used and integer ambiguities were estimated as float numbers instead of fixed integers. The result shows that, with BPAC and HPAC corrections, the horizontal accuracy is 46% and 63% higher, respectively, compared to that obtained without application of SPARTN corrections. Also, the average horizontal and vertical RMSE values with HPAC are 17 cm and 27 cm, respectively.

• International Journal of Computer Science & Network Security
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• 제22권8호
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• pp.97-104
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• 2022

European integration processes have acted as a catalyst for the emergence of a new type of educational environment, which is characterized by competent flexibility of specialists. Therefore, the article focuses on professional training of teachers in the context of European integration processes using information technology and the search for innovative methods of training specialists. One of the educational priorities in Europe is to create a new model of a teacher who has an academic education, knows innovative methods, is able to perform functions and tasks efficiently and professionally, adequately, quickly and correctly respond to changes and innovations. The tasks facing education in the European dimension are formulated. The main trends in the education of teachers in modern Europe are described: the need to deepen and expand subject training programs in pedagogical institutions of Higher Education, which will allow autonomy of activity, awareness of responsibility for independent creative decisions, create favorable conditions for the development of professionalism through the use of Information Technology and the search for innovative methods of training specialists. At the present stage, various models of teacher training are being developed based on the University and practical concept using information technology and searching for innovative methods of training specialists. On this basis, two different theories of perception of teacher education were formed: as preparation of teachers for work throughout their professional career; as preparation for the first years of professional work, which is periodically repeated in the process of continuous professional training and improvement. Among the advantages that the use of Information Technology and the search for innovative methods of training specialists to implement the learning process, it is worth mentioning the following: simultaneous use of several channels of perception of the student or student in the learning process, thanks to which the integration of information processed by different sensory organs is achieved; the ability to simulate complex real experiments; visualization of abstract information by dynamic representation of processes, etc.

• 한국전통조경학회지
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• 제32권3호
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• pp.82-95
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• 2014

본 연구는 전통공간의 수목정비방안 마련을 위해 광한루원을 사례로 진행되었다. 이를 위해 전통공간의 수종 선정과 수목정비 동향에 대한 이론적 고찰이 선행되었으며, 광한루원의 현장조사를 통한 식재현황을 분석하고, 과거 문헌 및 기록 등에 나타나는 수종 및 식재경관을 토대로 광한루원의 수목정비방안을 도출한 결과는 다음과 같다. 첫째, 전통공간의 수종 선정과 수목정비에 관한 동향을 살펴본 결과, 전통공간 내에 식재된 외래수종에 대하여 맹목적인 지양은 한계가 있으며 전통공간의 수종 선정에 대한 논의는 오늘날까지 이어져오고 있는 시점에서 수목정비에 대한 외래수종의 무분별한 제거 및 향토식물의 맹목적 식재 등의 이분법적 정비방안 및 비검증된 사료의 맹신은 배제되어야 한다. 둘째, 광한루원 내에 식재된 수종을 조사한 결과 소나무, 느티나무, 은행나무, 배롱나무 등 전통공간에서 애용되었던 수종들이 주로 식재되어 있으나 각 공간의 성격을 고려할 때, 광한루 일대를 제외한 광한루원 경내의 수목 식재는 전통공간의 성격과는 무관한 것으로 판단된다. 셋째, 문헌이나 문학작품 등에서 나타나는 광한루원의 수목식재 관련 기록을 살펴본 결과, 현재 광한루원 내에 식재된 수종 중 버드나무류, 배롱나무, 대나무(이대), 연꽃만이 나타나고 있어 고증을 통한 수목정비에는 무리가 따른다. 넷째, 광한루원의 각 권역별 수목정비방안을 모색한 결과, 광한루 권역은 역사적 시대성과 장소성을 지니고 있으며 오늘날 그 모습을 복원해나가고 있어 현재의 상태를 유지하는 방향으로 설정되어야 한다. 완월정 권역은 광한루의 건조물군과 유사한 형태로서 자칫 원형으로 오인될 수 있으므로 완충식재를 통한 전이 공간 조성 등 광한루 권역과는 다른 별도의 장소성 확보가 필요하다. 월매집 권역과 잔디광장 권역은 과거 성외 장시이자 대규모의 숲으로서 율림의 상징적 복원과 동시에 경내의 편의시설 및 관리시설의 집적을 통해 성외 장시의 모습을 재현하도록 하며, 완월정 동측 잔디광장은 완월정 권역과 연계하여 활용적 측면에서 현재와 같이 개방된 형태를 유지하는 방안을 제언하고자 한다. 광한루원 경계 권역은 고증의 측면과 현존요소의 진정성 여부를 살펴보았을 때 전통공간의 장소성과는 연관 짓기 어려운 장소로서 과거 문학작품에서 나타나는 문화경관을 반영하는 것 또한 하나의 정비방안으로 고려할 만하다 판단된다.

• 대기
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• 제23권4호
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• pp.453-470
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• 2013

As a part of the KIAPS Observation Processing System (KOPS), we have developed the modules of satellite radiance data pre-processing and quality control, which include observation operators to interpolate model state variables into radiances in observation space. AMSU-A (Advanced Microwave Sounding Unit-A) level-1d radiance data have been extracted using the BUFR (Binary Universal Form for the Representation of meteorological data) decoder and a first guess has been calculated with RTTOV (Radiative Transfer for TIROS Operational Vertical Sounder) version 10.2. For initial quality checks, the pixels contaminated by large amounts of cloud liquid water, heavy precipitation, and sea ice have been removed. Channels for assimilation, rejection, or monitoring have been respectively selected for different surface types since the errors from the skin temperature are caused by inaccurate surface emissivity. Correcting the bias caused by errors in the instruments and radiative transfer model is crucial in radiance data pre-processing. We have developed bias correction modules in two steps based on 30-day innovation statistics (observed radiance minus background; O-B). The scan bias correction has been calculated individually for each channel, satellite, and scan position. Then a multiple linear regression of the scan-bias-corrected innovations with several predictors has been employed to correct the airmass bias.