• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2002.11a
• /
• pp.139-143
• /
• 2002

1990 년대 후반부터 다양한 디지털 통신망을 이용하여 멀티미디어 컨텐츠 서비스가 가능하게 되었다. 하지만, 멀티미디어 컨텐츠의 전달 및 이용을 위한 기반 구조들의 독자적 발전 및 다양한 통합적 관리 체계 시스템으로 인해, 멀티미디어 컨텐츠 표현 방식의 호환성 문제, 혼재하는 네트워크 전달 방식과 단말 방식의 호환성 문제 등의 잠재적인 문제점이 발생한다. 이런 문제의 대안으로 현재 존재하는 기술 및 기반 구조들 사이의 연동을 통한 큰 프레임워크인 MPEG-21이 진행 중이다. MPEG-21 의 목표는 표준화 목표를 구체화하는 것부터 진행하여, 최종적으로 “다양한 네트워크 환경과 단말기에 있어서, 투명하고 통합적으로 멀티미디어 자원의 이용을 가능하게 하는 것”이다. 본 논문에서는 현재 표준화 작업이 진행 중인 MPEG-21 을 기반으로 하는 Testbed를 제안한다. Testbed는 server, client, DIA(Digital Item Adaptation) 의 세 모듈로 구성된다. Server 의 역할은 멀티미디어 컨텐츠를 Digital Item(DI)으로 생성하고, client 가 DI를 요구할 경우 DIA 모듈을 통해서 변환된 DI를 client 에게 제공한다. DIA 모듈은 server 에서 동작되며 client로부터 요청된 DI를 분석하고 client로부터 전송된 환경 정보를 이용하여 client 환경에 적합하게 변환된 (adapted) DI를 생성하는 것이 주 기능이다. Client 는 server 에 저장되어 있는 DI를 선택하고 user preference, terminal capability 등의 필요한 정보를 server로 전송한다. Testbed 에서는 스포츠 경기의 동영상, 정지 영상, 경기 내용 역사를 기록한 파일 등의 DI를 이용한다. 표현 언어는 XML이며, HTTP 기반의 Web 환경에서 구동되도록 설계된다.스템 사이에 의미 있는 데이터 전송, 지식 획득을 위해 정보 기술 분야에서 활용해야 할 영역으로 XML Web Services, Multi-agent Systems, 전문가 컴뮤니티를 위한 그룹웨어 연구 개발에 관해 사례 중심으로 발표한다.다 신선한 공기를 넣어 주었을 때는 배의 발달이 많이 늦어져 배양 3주째에 다른 처리보다 배의 수가 훨씬 적었다. 체세포배가 발달하는 동안에는 산소를 많이 요구하지 않으나 성숙하는 동안에는 산소를 많이 요구하는 것으로 생각된다.적인 것으로 나타났다. 다만, 곡선형은 물론 직선형에서도 열교환 튜브의 배치밀도, 튜브 길이 및 두께 등의 변화에 따른 최적화 연구가 수반되어야 할 것으로 판단된다.에서 제공된 API는 객체기반 제작/편집 도구에 응용되어 다양한 멀티미디어 컨텐츠 제작에 사용되었다.x factorization (NMF), generative topographic mapping (GTM)의 구조와 학습 및 추론알고리즘을소개하고 이를 DNA칩 데이터 분석 평가 대회인 CAMDA-2000과 CAMDA-2001에서 사용된cancer diagnosis 문제와 gene-drug dependency analysis 문제에 적용한 결과를 살펴본다.0$\mu$M이 적당하며, 초기배발달을 유기할 때의 효과적인 cysteamine의 농도는 25~50$\mu$M인 것으로 판단된다.N)A(N)/N을 제시하였다(A(N)=N에 대한 A값). 위의 실험식을 사용하여 헝가리산 Zempleni 시료(15%$S_{XRD}$)의 기본입자분포로부터 %$S_{XRD}$를 계산한 결과, 16%$S_{XRD}$의 결과값을 얻을 수 있었다. 따라서, 본 연구에서 도출한 관계식들이 유효함을 확인할 수 있었다.계식들이 유효함을 확인할 수 있었다.할 때 약간의 증가

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.11A
• /
• pp.1081-1091
• /
• 2005

Unlike conventional DVB-T transmission with the streaming method, DVB-H system based on the IPDC(IP Data Casting) method uses Time-slicing scheme to achieve the maximization of portability by reducing the power consumption of a receiver. To enhance the power efficiency of the receiver, Time-slicing scheme controls the receiver operation to perform only for corresponding burst in specific time slot. The additional power saving can also be achieved by reducing the required time for synchronization. In this paper, we propose a fast scattered pilot synchronization algorithm, which detects the pilot pattern of currently received OFDM symbol. The proposed scheme is based on the correlation between the adjacent subcarriers of potential scattered pilot position in two consecutively received OFDM symbols. Therefore, it can reduce the time for the scattered pilot synchronization within two symbols as com-pared with the conventional method used for DVB-T. And the proposed algorithm has better performance than the two schemes proposed by Nokia for DVB-H and the method using correlation with reference signal. Extensive com-puter simulation is performed based on ETSI EN300 744 ETSI and performance results show that the proposed algorithm has more efficient and stable operation than the conventional schemes.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.42 no.4
• /
• pp.716-722
• /
• 2017

In this paper, a fully printed NFC tag operating at 13.56 MHz was designed and fabricated using silver nano-paste and carbon ink. The proposed NFC tag has a printed coil with an inductance of $2.74{\mu}H$ on a PI film for application to an NFC tag IC with an internal capacitance of 50 pF. Screen printing technology used in this paper has advantages such as large area printing for mass production, low cost and eco-friendly process compared to conventional PCB manufacturing process. The proposed structure consists of a circular coil implemented as a single layer using silver nano-paste and carbon ink, a jumper pattern for chip mounting between the outer edge and the center of the coil, and an insulation pattern between the coil and the jumper pattern. In order to verify the performance of the proposed NFC tag, we performed the measurements of the printing line width, thickness, line resistance, adhesion and environmental reliability, and confirmed the suitability of the NFC tag based on the full-printed manufacturing method.

• Journal of the Korean Magnetics Society
• /
• v.23 no.2
• /
• pp.49-53
• /
• 2013

A current sensor is one of important component which is used for the electrical current measurement during charge and discharge of the battery, and monitoring system of the motor controller in the electric and hybrid vehicle. In this study, we have developed an open loop type current sensor using GaAs Hall sensor and magnetic core has an air gap. The Hall sensor detect magnetic field produced by the current to be measured. The 3 mm air gap core was made by HGO electrical steel sheets after slitting, winding, annealing, molding, and cutting. Developed current sensor shows 0.03 % linearity within DC current range from -400 A to +400 A. Operating temperature range was extended to the range of $-40{\sim}105^{\circ}C$ using temperature compensating electronic circuit. To Improve frequency bandwidth limit due to the air flux of PCB (Printed Circuit Board) and Hall sensor, We employed an air flux compensating loop near Hall sensor or on PCB. Frequency bandwidth of the sensor was 100 kHz when we applied sine wave current of $40A{\cdot}turn$ in the frequency range from 100 Hz to 100 kHz. For the dynamic response time measurement, 5 kHz square wave current of $40A{\cdot}turn$ was applied to the sensor. Response time was calculated time reach to 90 % of saturation value and smaller than $2{\mu}s$.

• Geophysics and Geophysical Exploration
• /
• v.12 no.1
• /
• pp.41-48
• /
• 2009

Natural magnetic fields are attenuated by electrically conductive water. For that reason, marine magnetotelluric surveys have collected data at long periods (1000-100 000 s). The mantle structure has been the main target of seafloor magnetotelluric measurements. To ascertain crustal structure, however, electromagnetic data at shorter periods are important, e.g. in investigations of megathrust earthquake zones, or in natural resource surveys. To investigate of the former, for example, electromagnetic data for periods of less than 1000 s are necessary. Because no suitable ocean bottom electromagnetometer (OBEM) has been available, we have developed a small OBEM and ocean bottom electrometer (OBE) system with a high sample rate, which has an arm-folding mechanism to facilitate assembly and recovering operations. For magnetic observation, we used a fluxgate sensor. Field observations were undertaken to evaluate the field performance of our instruments. All instruments were recovered and their electromagnetic data were obtained. Results of the first experiment show that our system functioned well throughout operations and observations. Results of other field experiments off Tottori support the claim that the electromagnetic data obtained using the new OBEM and OBE system are of sufficient quality for the survey target. These results suggest that this device removes all instrumental obstacles to measurement of electromagnetic fields on the seafloor.

• Korean Journal of Applied Biomechanics
• /
• v.14 no.1
• /
• pp.117-131
• /
• 2004

The foreign superior players and national team players' turning phase was measured, compared and analyzed to help the representative players improve the skill of turn. The underwater video camera used to analyze and evaluate the representative players' skill of turn in detail and the result is as follows. 1. The record for the phase of turn was similar to the rank of the last record. The improvement of the skill of turn was required because Korean players' record was lower than the foreign players' one. In case of 200m events the 1st turn was the fastest and it took more time as the turn is repeated. 2. It shows that the preparation phase and turing motion cause the difference between the players and within one player. 3. The horizontal movement of center of gravity moves to turning point slowly in the preparation phase, does not move nearly in the turning phase and increase again in the propulsion phase. Good record has short time for turn phase. The result means that the shorten the turning phase is the most important factor. Therefore the preparation for this is required. The vertical movement is maintained or increase a little and then move to from the turning phase. 4. The characteristic of horizontal velocity in center of gravity is that there is any big changes at the preparation phase, the faster velocity is found from the better record and the accelerating time is fast at the propulsion phasen. The wrong motion is made by not using the swimming velocity for fuming and waiting and more time is required by this. 5. The angle of knee when the player touch the turning point is 106.22-135.56 and the maximum angle of knee during the driving after the touch of tuning point is full extension. The size of maximum angle of knee did not match with the required time of propulsion phase. It seems that the individual difference is big when the players touch the turning point the angle of knee and the research for the individual angle which can reveal the maximum power should be carried out. The national team player's skill for the him is behind the foreign players' one and a lot of problems were found. It shows that the players could not practice the skill for turn during the training. The 1st reason for it is the various facilities like underwater window or analyzing equipment like underwater camera with which the coaches can teach and correct the players' detailed skill. It is need to evaluate the players' detailed skill exactly and correct it by objective data to complete the good skill in the future. In this regard, the investment for the facility is necessary.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.9 no.2
• /
• pp.137-144
• /
• 2015

In this paper, we present an inertial sensor-based gait analysis system to measure and analyze lower-limb movements. We developed an integral AHRS(Attitude Heading Reference System) using a combination of rate gyroscope, accelerometer and magnetometer sensor signals. Several AHRS modules mounted on segments of the patient's body provide the quaternions representing the patient segments's orientation in space. And a method is also proposed for calculating three-dimensional inter-segment joint angle which is an important bio-mechanical measure for a variety of applications related to rehabilitation. To evaluate the performance of our AHRS module, the Vicon motion capture system, which offers millimeter resolution of 3D spatial displacements and orientations, is used as a reference. The evaluation resulted in a RMSE(Root Mean Square Error) of 1.08 and 1.72 degree in yaw and pitch angle. In order to evaluate the performance of our the gait analysis system, we compared the joint angle for the hip, knee and ankle with those provided by Vicon system. The result shows that our system will provide an in-depth insight into the effectiveness, appropriate level of care, and feedback of the rehabilitation process by performing real-time limb or gait analysis during the post-stroke recovery.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.19 no.5
• /
• pp.162-177
• /
• 2020

The perception of traffic environment based on various sensors in autonomous driving system has a direct relationship with driving safety. Recently, as the perception model based on deep neural network is used due to the development of machine learning/in-depth neural network technology, a the perception model training and high quality of a training dataset are required. However, there are several realistic difficulties to collect data on all situations that may occur in self-driving. The performance of the perception model may be deteriorated due to the difference between the overseas and domestic traffic environments, and data on bad weather where the sensors can not operate normally can not guarantee the qualitative part. Therefore, it is necessary to build a virtual road environment in the simulator rather than the actual road to collect the traning data. In this paper, a training dataset collection process is suggested by diversifying the weather, illumination, sensor position, type and counts of vehicles in the simulator environment that simulates the domestic road situation according to the domestic situation. In order to achieve better performance, the authors changed the domain of image to be closer to due diligence and diversified. And the performance evaluation was conducted on the test data collected in the actual road environment, and the performance was similar to that of the model learned only by the actual environmental data.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.42 no.6
• /
• pp.37-48
• /
• 2005

The efficiency of power supply circuits such as DC-DC converters and batteries varies on the trend of the power consumption because their efficiencies are not fixed. To analyze the efficiency of power supply circuits, we need the temporal behavior of the power consumption of the loads, which is dependent on the activity factors of the devices during the operation. Since it is not easy to model every detail of those factors, one of the most accurate power consumption analyses of power supply circuits is measurement of a real system, which is expensive and time consuming. In this paper, we introduce an active load emulator for embedded systems which is capable of power measurement, logging, replaying and synthesis. We adopt a pattern recognition technique for data compression in that long-term behaviors of power consumption consist of numbers of repetitions of short-term behaviors, and the number of short-term behaviors is generally limited to a small number. We also devise a heterogeneous structure of active load elements so that low-speed, high-current active load elements and high-speed, low-current active load elements may emulate large amount and fast changing power consumption of digital systems. For the performance evaluation of our load emulator, we demonstrate power measurement and emulation of a hard drive. As an application of our load emulator, it is used for the analysis of a DC-DC converter efficiency and for the verification of a low-power frequency scaling policy for a real-time task.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.39 no.6
• /
• pp.34-42
• /
• 2002

In this paper, we propose a temperature independent the detective voltage source in voltage detector. The value of a detective voltage source is designed to become m times of silicon bandgap voltage at zero absolute temperature. By properly choosing the temperature coefficient of diode, the temperature coefficient of a concave voltage nonlinearities generated by the ${\Delta}V_{BE}$ section of diode between base and emitter of transistors with a different area can be summed with convex nonlinearities the $V_{BE}$ voltage to achieve the near zero temperature coefficient of the detective voltage source. We designed that the value of a detective voltage can be varied by ${\Delta}V_{BE}$, the $V_{BE}$multiplier circuit and resistor. In order to verify the performance of a proposed detective voltage source, we manufactured the voltage detector IC for 1.9V which is fabricated in $6{\mu}m$ Bipolar technology and measured the operating characteristics, the temperature coefficient of a detective voltage. To reduce the deviation of a detective voltage in the IC process step, we introduced a trimming technology, ion implantation and an isotropic etching. In manufactured IC, the detective voltage source could achieve the stable temperature coefficient of 29ppm/$^{\circ}C$ over the temperature range of -30$^{\circ}C$ to 70$^{\circ}C$. The current consumption of a voltage detector constituted by the proposed detective voltage source is $10{\mu}A$ from 1.9V-supply voltage at room temperature.