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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
Electronics and Telecommunications Research Institute
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Volume & Issues
Volume 35, Issue 6 - Dec 2013
Volume 35, Issue 5 - Oct 2013
Volume 35, Issue 4 - Aug 2013
Volume 35, Issue 3 - Jun 2013
Volume 35, Issue 2 - Apr 2013
Volume 35, Issue 1 - Feb 2013
Selecting the target year
Fast Random-Forest-Based Human Pose Estimation Using a Multi-scale and Cascade Approach
Chang, Ju Yong ; Nam, Seung Woo ;
ETRI Journal, volume 35, issue 6, 2013, Pages 949~959
DOI : 10.4218/etrij.13.2013.0063
Since the recent launch of Microsoft Xbox Kinect, research on 3D human pose estimation has attracted a lot of attention in the computer vision community. Kinect shows impressive estimation accuracy and real-time performance on massive graphics processing unit hardware. In this paper, we focus on further reducing the computation complexity of the existing state-of-the-art method to make the real-time 3D human pose estimation functionality applicable to devices with lower computing power. As a result, we propose two simple approaches to speed up the random-forest-based human pose estimation method. In the original algorithm, the random forest classifier is applied to all pixels of the segmented human depth image. We first use a multi-scale approach to reduce the number of such calculations. Second, the complexity of the random forest classification itself is decreased by the proposed cascade approach. Experiment results for real data show that our method is effective and works in real time (30 fps) without any parallelization efforts.
Cloud-Based Gaming Service Platform Supporting Multiple Devices
Kim, Kyoung Ill ; Bae, Su Young ; Lee, Dong Chun ; Cho, Chang Sik ; Lee, Hun Joo ; Lee, Kyu Chul ;
ETRI Journal, volume 35, issue 6, 2013, Pages 960~968
DOI : 10.4218/etrij.13.2013.0076
To implement a cloud game service platform supporting multiple users and devices based on real-time streaming, there are many technical needs, including game screen and sound capturing, audio/video encoding in real time created by a high-performance server-generated game screen, and real-time streaming to client devices, such as low-cost PCs, smart devices, and set-top boxes. We therefore present a game service platform for the running and management of the game screen, as well as running the sound on the server, in which the captured and encoded game screen and sound separately provide client devices through real-time streaming. The proposed platform offers Web-based services that allow game play on smaller end devices without requiring the games to be installed locally.
Spectrum-Based Color Reproduction Algorithm for Makeup Simulation of 3D Facial Avatar
Jang, In-Su ; Kim, Jae Woo ; You, Ju-Yeon ; Kim, Jin Seo ;
ETRI Journal, volume 35, issue 6, 2013, Pages 969~979
DOI : 10.4218/etrij.13.2013.0079
Various simulation applications for hair, clothing, and makeup of a 3D avatar can provide more useful information to users before they select a hairstyle, clothes, or cosmetics. To enhance their reality, the shapes, textures, and colors of the avatars should be similar to those found in the real world. For a more realistic 3D avatar color reproduction, this paper proposes a spectrum-based color reproduction algorithm and color management process with respect to the implementation of the algorithm. First, a makeup color reproduction model is estimated by analyzing the measured spectral reflectance of the skin samples before and after applying the makeup. To implement the model for a makeup simulation system, the color management process controls all color information of the 3D facial avatar during the 3D scanning, modeling, and rendering stages. During 3D scanning with a multi-camera system, spectrum-based camera calibration and characterization are performed to estimate the spectrum data. During the virtual makeup process, the spectrum data of the 3D facial avatar is modified based on the makeup color reproduction model. Finally, during 3D rendering, the estimated spectrum is converted into RGB data through gamut mapping and display characterization.
Stereo Video Retargeting with Representative Seams in a Group of Stereoscopic Frames
Nguyen, Hai Thanh ; Won, Chee Sun ;
ETRI Journal, volume 35, issue 6, 2013, Pages 980~989
DOI : 10.4218/etrij.13.2013.0032
The important requirements for stereo video retargeting are threefold: keeping temporal coherence, preventing depth distortion, and minimizing shape distortions of the retargeted video. To meet these requirements, the left and right video sequences are divided into groups of frames (GoFs), where the GoF is a basic unit for the seam carving and we assign a set of fixed seams for all frames within the GoF. To determine the fixed seams for each GoF, we need to find the GoF boundary in the video first. Then, the representative frame for each GoF is generated by considering the spatial saliency and temporal coherence. Also, the confidence of the stereoscopic correspondence between the left and right frames is considered to prevent depth distortion.
Scalable Extension of HEVC for Flexible High-Quality Digital Video Content Services
Lee, Hahyun ; Kang, Jung Won ; Lee, Jinho ; Choi, Jin Soo ; Kim, Jinwoong ; Sim, Donggyu ;
ETRI Journal, volume 35, issue 6, 2013, Pages 990~1000
DOI : 10.4218/etrij.13.2013.0040
This paper describes the scalable extension of High Efficiency Video Coding (HEVC) to provide flexible high-quality digital video content services. The proposed scalable codec is designed on multi-loop decoding architecture to support inter-layer sample prediction and inter-layer motion parameter prediction. Inter-layer sample prediction is enabled by inserting the reconstructed picture of the reference layer (RL) into the decoded picture buffer of the enhancement layer (EL). To reduce the motion parameter redundancies between layers, the motion parameter of the RL is used as one of the candidates in merge mode and motion vector prediction in the EL. The proposed scalable extension can support scalabilities with minimum changes to the HEVC and provide average Bj
ntegaard delta bitrate gains of about 24% for spatial scalability and of about 21% for SNR scalability compared to simulcast coding with HEVC.
Sensible Media Simulation in an Automobile Application and Human Responses to Sensory Effects
Kim, Sang-Kyun ; Joo, Yong-Soo ; Lee, YoungMi ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1001~1010
DOI : 10.4218/etrij.13.2013.0038
A sensible media simulation system for automobiles is introduced to open up new possibilities for an in-car entertainment system. In this paper, the system architecture is presented, which includes a virtuality-to-reality adaptation scheme. Standard data schemes for context and control information from the International Standard MPEG-V (ISO/IEC 23005) are introduced to explain the details of data formats, which are interchangeable in the system. A sensible media simulator and the implementation of a sensory device are presented to prove the effectiveness of the proposed system. Finally, a correlation between learning styles and sensory effects (that is, wind and vibration effects) is statistically analyzed using the proposed system. The experiment results show that the level of satisfaction with the sensory effects is unaffected overall by the learning styles of the test subjects. Stimulations by vibration effects, however, generate more satisfaction in people with a high tactile perception level or a low visual perception level.
High-Quality Stereo Depth Map Generation Using Infrared Pattern Projection
Jeong, Jae-Chan ; Shin, Hochul ; Chang, Jiho ; Lim, Eul-Gyun ; Choi, Seung Min ; Yoon, Kuk-Jin ; Cho, Jae-Il ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1011~1020
DOI : 10.4218/etrij.13.2013.0052
In this paper, we present a method for obtaining a high-quality 3D depth. The advantages of active pattern projection and passive stereo matching are combined and a system is established. A diffractive optical element (DOE) is developed to project the active pattern. Cross guidance (CG) and auto guidance (AG) are proposed to perform the passive stereo matching in a stereo image in which a DOE pattern is projected. When obtaining the image, the CG emits a DOE pattern periodically and consecutively receives the original and pattern images. In addition, stereo matching is performed using these images. The AG projects the DOE pattern continuously. It conducts cost aggregation, and the image is restored through the process of removing the pattern from the pattern image. The ground truth is generated to estimate the optimal parameter among various stereo matching algorithms. Using the ground truth, the optimal parameter is estimated and the cost computation and aggregation algorithm are selected. The depth is calculated and bad-pixel errors make up 4.45% of the non-occlusion area.
Hybrid Facial Representations for Emotion Recognition
Yun, Woo-Han ; Kim, DoHyung ; Park, Chankyu ; Kim, Jaehong ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1021~1028
DOI : 10.4218/etrij.13.2013.0054
Automatic facial expression recognition is a widely studied problem in computer vision and human-robot interaction. There has been a range of studies for representing facial descriptors for facial expression recognition. Some prominent descriptors were presented in the first facial expression recognition and analysis challenge (FERA2011). In that competition, the Local Gabor Binary Pattern Histogram Sequence descriptor showed the most powerful description capability. In this paper, we introduce hybrid facial representations for facial expression recognition, which have more powerful description capability with lower dimensionality. Our descriptors consist of a block-based descriptor and a pixel-based descriptor. The block-based descriptor represents the micro-orientation and micro-geometric structure information. The pixel-based descriptor represents texture information. We validate our descriptors on two public databases, and the results show that our descriptors perform well with a relatively low dimensionality.
Fast Motion Synthesis of Quadrupedal Animals Using a Minimum Amount of Motion Capture Data
Sung, Mankyu ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1029~1037
DOI : 10.4218/etrij.13.2013.0059
This paper introduces a novel and fast synthesizing method for 3D motions of quadrupedal animals that uses only a small set of motion capture data. Unlike human motions, animal motions are relatively difficult to capture. Also, it is a challenge to synthesize continuously changing animal motions in real time because animals have various gait types according to their speed. The algorithm proposed herein, however, is able to synthesize continuously varying motions with proper limb configuration by using only one single cyclic animal motion per gait type based on the biologically driven Froude number. During the synthesis process, each gait type is automatically determined by its speed parameter, and the transition motions, which have not been entered as input, are synthesized accordingly by the optimized asynchronous motion blending technique. At the start time, given the user's control input, the motion path and spinal joints for turning are adjusted first and then the motion is stitched at any speed with proper transition motions to synthesize a long stream of motions.
In-Vehicle AR-HUD System to Provide Driving-Safety Information
Park, Hye Sun ; Park, Min Woo ; Won, Kwang Hee ; Kim, Kyong-Ho ; Jung, Soon Ki ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1038~1047
DOI : 10.4218/etrij.13.2013.0041
Augmented reality (AR) is currently being applied actively to commercial products, and various types of intelligent AR systems combining both the Global Positioning System and computer-vision technologies are being developed and commercialized. This paper suggests an in-vehicle head-up display (HUD) system that is combined with AR technology. The proposed system recognizes driving-safety information and offers it to the driver. Unlike existing HUD systems, the system displays information registered to the driver's view and is developed for the robust recognition of obstacles under bad weather conditions. The system is composed of four modules: a ground obstacle detection module, an object decision module, an object recognition module, and a display module. The recognition ratio of the driving-safety information obtained by the proposed AR-HUD system is about 73%, and the system has a recognition speed of about 15 fps for both vehicles and pedestrians.
An Immersive Augmented-Reality-Based e-Learning System Based on Dynamic Threshold Marker Method
Lim, Sukhyun ; Lee, Junsuk ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1048~1057
DOI : 10.4218/etrij.13.2013.0081
In recent years, augmented reality (AR) technologies have been the subject of great interest among many communities. In education applications, old-fashioned materials (or textbooks) are still used, despite remarkable AR developments in the industrial area. We present an AR system for education. Our system consists of an authoring tool that can be used to create educational content, a viewer that plays that content, and an engine to manage the tool and viewer. In our system, a marker unit recognizes a marker printed on a plane or a cubic plane by adaptively adjusting the threshold to have an excellent recognition rate in diverse environments and acquires corresponding data of the marker. Based on the system, we test 142 elementary school students for increased educational benefits using our system.
Game Bot Detection Approach Based on Behavior Analysis and Consideration of Various Play Styles
Chung, Yeounoh ; Park, Chang-Yong ; Kim, Noo-Ri ; Cho, Hana ; Yoon, Taebok ; Lee, Hunjoo ; Lee, Jee-Hyong ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1058~1067
DOI : 10.4218/etrij.13.2013.0049
An approach for game bot detection in massively multiplayer online role-playing games (MMORPGs) based on the analysis of game playing behavior is proposed. Since MMORPGs are large-scale games, users can play in various ways. This variety in playing behavior makes it hard to detect game bots based on play behaviors. To cope with this problem, the proposed approach observes game playing behaviors of users and groups them by their behavioral similarities. Then, it develops a local bot detection model for each player group. Since the locally optimized models can more accurately detect game bots within each player group, the combination of those models brings about overall improvement. Behavioral features are selected and developed to accurately detect game bots with the low resolution data, considering common aspects of MMORPG playing. Through the experiment with the real data from a game currently in service, it is shown that the proposed local model approach yields more accurate results.
Graceful Degradation FEC Layer for Multimedia Broadcast/Multicast Service in LTE Mobile Systems
Won, Seok Ho ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1068~1074
DOI : 10.4218/etrij.13.0113.0486
This paper proposes an additional forward error correction (FEC) layer to compensate for the defectiveness inherent in the conventional FEC layer in the Long Term Evolution specifications. The proposed additional layer is called a graceful degradation (GD)-FEC layer and maintains desirable service quality even under burst data loss conditions of a few seconds. This paper also proposes a non-delayed decoding (NDD)-GD-FEC layer that is inherent in the decoding process. Computer simulations and device-based tests show a better loss recovery performance with a negligible increase in CPU utilization and occupied memory size.
Design of an Ultra-Wideband Antenna Using a Ring Resonator with a Notch Function
Lee, Jung-Nam ; Kwon, Heon-Kook ; Kang, Byung-Su ; Lee, Kwang-Chun ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1075~1083
DOI : 10.4218/etrij.13.0113.0472
This paper describes an ultra-wideband (UWB) antenna that uses a ring resonator concept. The proposed antenna can operate in the entire UWB, and the IEEE 802.11a frequency band can be rejected by inserting a notch stub into the ring resonator. The experiment results indicate that the measured impedance bandwidth of the proposed antenna is 17.5 GHz (2.5 GHz to at least 20 GHz). The proposed UWB antenna has omnidirectional radiation patterns with a gain variation of 3 dBi (1 dBi to 4 dBi).
P2P Ranging-Based Cooperative Localization Method for a Cluster of Mobile Nodes Containing IR-UWB PHY
Cho, Seong Yun ; Kim, Joo Young ; Enkhtur, Munkhzul ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1084~1093
DOI : 10.4218/etrij.13.0112.0823
problem of pedestrian localization using mobile nodes containing impulse radio ultra wideband (IR-UWB) is considered. IEEE 802.15.4a-based IR-UWB can achieve accurate ranging. However, the coverage is as short as 30 m, owing to the restricted transmit power. This factor may cause a poor geometric relationship among the mobile nodes and anchor nodes in certain environments. To localize a group of pedestrians accurately, an enhanced cooperative localization method is proposed. We describe a sequential algorithm and define problems that may occur in the implementation of the algorithm. To solve these problems, a batch algorithm is proposed. The batch algorithm can be carried out after performing the sequential algorithm to linearize the nonlinear range equation. When a sequential algorithm cannot be performed due to a poor geometric relationship among nodes, a batch algorithm can be carried out directly. Herein, Monte Carlo simulations are presented to illustrate the proposed method and verify its performance.
Automating Configuration System and Protocol for Next-Generation Home Appliances
Lee, Eun-Seo ; Lee, Hark-Jin ; Lee, Kwangil ; Park, Jun-Hee ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1094~1104
DOI : 10.4218/etrij.13.0113.0216
Home appliance manufacturers have recently been trying to provide smart products capable of various Internet services. For example, one health care manufacturer provides a Wi-Fi-capable scale. Once users register their information with the manufacturer's server, their weight and body fat records are automatically uploaded to the server whenever they measure their weight. The users can then watch and check their weight log easily using a smart device, such as a smartphone or tablet. One of the biggest problems, however, is that the initial configuration of the appliances and the user registration process may be quite complicated to typical users who are unfamiliar with such IT devices. This paper proposes an autoconfiguration system structure and protocol for Internet-capable home appliances, which supports the initial configuration and remote maintenance service of the device with only little user effort. Manufacturers can develop their own information appliances and provide differentiated services using the proposed system and protocol.
Extraction of User Preference for Video Stimuli Using EEG-Based User Responses
Moon, Jinyoung ; Kim, Youngrae ; Lee, Hyungjik ; Bae, Changseok ; Yoon, Wan Chul ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1105~1114
DOI : 10.4218/etrij.13.0113.0194
Owing to the large number of video programs available, a method for accessing preferred videos efficiently through personalized video summaries and clips is needed. The automatic recognition of user states when viewing a video is essential for extracting meaningful video segments. Although there have been many studies on emotion recognition using various user responses, electroencephalogram (EEG)-based research on preference recognition of videos is at its very early stages. This paper proposes classification models based on linear and nonlinear classifiers using EEG features of band power (BP) values and asymmetry scores for four preference classes. As a result, the quadratic-discriminant-analysis-based model using BP features achieves a classification accuracy of 97.39% (
), and the models based on the other nonlinear classifiers using the BP features achieve an accuracy of over 96%, which is superior to that of previous work only for binary preference classification. The result proves that the proposed approach is sufficient for employment in personalized video segmentation with high accuracy and classification power.
Geometric Correction for Uneven Quadric Projection Surfaces Using Recursive Subdivision of B
Ahmed, Atif ; Hafiz, Rehan ; Khan, Muhammad Murtaza ; Cho, Yongju ; Cha, Jihun ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1115~1125
DOI : 10.4218/etrij.13.0112.0597
This paper presents a scheme for geometric correction of projected content for planar and quadratic projection surfaces. The scheme does not require the projection surface to be perfectly quadratic or planar and is therefore suitable for uneven low-cost commercial and home projection surfaces. An approach based on the recursive subdivision of second-order B
zier patches is proposed for the estimation of projection distortion owing to surface imperfections. Unlike existing schemes, the proposed scheme is completely automatic, requires no prior knowledge of the projection surface, and uses a single uncalibrated camera without requiring any physical markers on the projection surface. Furthermore, the scheme is scalable for geometric calibration of multi-projector setups. The efficacy of the proposed scheme is demonstrated using simulations and via practical experiments on various surfaces. A relative distortion error metric is also introduced that provides a quantitative measure of the suppression of geometric distortions, which occurs as the result of an imperfect projection surface.
Identifying the Winner's Curse in the First Spectrum Auction in the Republic of Korea Using an Event Study Approach
Lee, Hyeongjik ; Seol, Seongho ; Kweon, Soocheon ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1126~1133
DOI : 10.4218/etrij.13.0112.0743
The first spectrum auction in the Republic of Korea is attention-worthy owing to the fierce competition for the only 1.8-GHz spectrum license, the winning bidder of which was suspected of overpaying for its acquisition. This study empirically investigates the existence of a "winner's curse" in the first Korean spectrum auction by using a standard event study methodology. The results show that both the winner and loser experienced significant positive returns on the completion day of the auction. The results imply that there was no winner's curse in the auction and that the losing firm might increase its competitive advantage by acquiring other spectrum licenses despite failing to achieve its initial target spectrum. Therefore, these results suggest that regulators may need to consider bringing about positive short-term wealth benefits to all bidders by appropriately designing a spectrum auction, such as by performing multiband auctions.
Characteristics of ICT-Based Converging Technologies
Kim, Pang Ryong ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1134~1143
DOI : 10.4218/etrij.13.0113.0043
The rising pace of technological change in information and communications technology (ICT) has provoked technological convergence by providing a new mode of diversification. This paper investigates the nature of ICT-based converging technologies by examining comparative empirical evidence on converging versus nonconverging technologies in relation to the following issues: patent application trends, concentration across technologies, the concentration of patenting activity across firms, R&D efforts, and a technology impact index. For this study, a new operational definition of ICT-based converging technology is derived, and a massive quantity of patents, up to around 600,000, is analyzed. This study follows the International Patent Classification as well as the modified European Commission's industry classification system for the classification of technologies and industries, respectively.
Smart WLAN Discovery for Power Saving of Dual-Mode Terminals
Park, Hyunho ; Lee, Hyeong Ho ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1144~1147
DOI : 10.4218/etrij.13.0213.0404
Dual-mode terminals (DMTs) equipped with cellular and WLAN interfaces have become popular in recent years. Users of DMTs can enjoy high-speed WLAN Internet access and wide area Internet access to cellular networks. However, a DMT may consume power inefficiently when discovering a WLAN with inherently limited service coverage. In this letter, we propose to use smart WLAN discovery (SWD) to minimize the power consumption required for WLAN discovery. To minimize the power consumption of a DMT, an SWD DMT activates its WLAN interface only when the DMT transfers data within the WLAN coverage area. The simulation results of SWD show an improved power-saving performance compared to previous WLAN discovery schemes.
A Low-Cost Method to Evaluate Absorber Reflectivity Using an Antenna with a Small Radiating Aperture and Frequency-Domain Instrument
Oh, Soon-Soo ; Lee, Young Hwan ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1148~1151
DOI : 10.4218/etrij.13.0213.0314
We propose a way to measure the absorber reflectivity at a low cost. Only one simple antenna with a small radiating aperture and a frequency-domain instrument are utilized. The previously used equation for calculating the reflectivity of an absorber is inaccurate, and, therefore, a new equation is derived based on multiple reflection analysis and three test models. Notably, the reflection coefficient of the antenna is included in the derived equation. The accuracy of the proposed method is proven through simulation and measurements. It can be easily applied to a product examination by absorber manufacturers and customers owing to its advantages of simplicity, cost effectiveness, and non-cutting examination.
Fine-Pitch Solder on Pad Process for Microbump Interconnection
Bae, Hyun-Cheol ; Lee, Haksun ; Choi, Kwang-Seong ; Eom, Yong-Sung ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1152~1155
DOI : 10.4218/etrij.13.0213.0284
A cost-effective and simple solder on pad (SoP) process is proposed for a fine-pitch microbump interconnection. A novel solder bump maker (SBM) material is applied to form a 60-
pitch SoP. SBM, which is composed of ternary Sn3.0Ag0.5Cu (SAC305) solder powder and a polymer resin, is a paste material used to perform a fine-pitch SoP through a screen printing method. By optimizing the volumetric ratio of the resin, deoxidizing agent, and SAC305 solder powder, the oxide layers on the solder powder and Cu pads are successfully removed during the bumping process without additional treatment or equipment. Test vehicles with a daisy chain pattern are fabricated to develop the fine-pitch SoP process and evaluate the fine-pitch interconnection. The fabricated Si chip has 6,724 bumps with a 45-
diameter and 60-
pitch. The chip is flip chip bonded with a Si substrate using an underfill material with fluxing features. Using the fluxing underfill material is advantageous since it eliminates the flux cleaning process and capillary flow process of the underfill. The optimized bonding process is validated through an electrical characterization of the daisy chain pattern. This work is the first report on a successful operation of a fine-pitch SoP and microbump interconnection using a screen printing process.
The Characteristics of
Thin Films Deposited Using RF-Magnetron Sputtering Method with Nitrogen-Ambient
Lee, Seong Hyun ; Yun, Sun Jin ; Lim, Jung Wook ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1156~1159
DOI : 10.4218/etrij.13.0213.0216
We investigate the characteristics of
thin films deposited through the addition of
gas. The addition of
gas has remarkable effects on the phase changes, resulting in improved electrical and optical properties. An intermediate phase (
) appears at a
flow rate of 1 sccm, and a
(200) phase is then preferentially grown at a higher feeding amount of
. The optical and electrical properties of
thin films are improved with a sufficient
flow rate of more than 15 sccm, as confirmed through various analyses. Under this condition, a high bandgap energy of 2.58 eV and a conductivity of
S/cm are obtained. These high-quality
thin films are expected to be applied to
-based heterojunction solar cells and optical functional films.
Multidirectional Pointing Input Using a Hardware Keyboard
Lee, Byungjoo ; Park, Haesun ; Bang, Hyunwoo ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1160~1163
DOI : 10.4218/etrij.13.0213.0117
Herein, we propose a novel method to create multidirectional and multilevel pointing input using only a hardware keyboard. The relative position vectors among pressed keys are calculated into an input vector. The pointing performance of this method is evaluated based on the ISO 9241-9 recommendations. We find that the performance of the method is sufficient to create moderate pointing input, as the measurement of the throughput is close to that of a touchpad, as measured in past studies also using the ISO 9241-9 recommendations.
Analysis of Failure in Miniature X-ray Tubes with Gated Carbon Nanotube Field Emitters
Kang, Jun-Tae ; Kim, Jae-Woo ; Jeong, Jin-Woo ; Choi, Sungyoul ; Choi, Jeongyong ; Ahn, Seungjoon ; Song, Yoon-Ho ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1164~1167
DOI : 10.4218/etrij.13.0213.0346
We correlate the failure in miniature X-ray tubes with the field emission gate leakage current of gated carbon nanotube emitters. The miniature X-ray tube, even with a small gate leakage current, exhibits an induced voltage on the gate electrode by the anode bias voltage, resulting in a very unstable operation and finally a failure. The induced gate voltage is apparently caused by charging at the insulating spacer of the miniature X-ray tube through the gate leakage current of the field emission. The gate leakage current could be a criterion for the successful fabrication of miniature X-ray tubes.
Enhancement of Particle Swarm Optimization by Stabilizing Particle Movement
Kim, Hyunseok ; Chang, Seongju ; Kang, Tae-Gyu ;
ETRI Journal, volume 35, issue 6, 2013, Pages 1168~1171
DOI : 10.4218/etrij.13.0213.0197
We propose an improvement of particle swarm optimization (PSO) based on the stabilization of particle movement (PM). PSO uses a stochastic variable to avoid an unfortunate state in which every particle quickly settles into a unanimous, unchanging direction, which leads to overshoot around the optimum position, resulting in a slow convergence. This study shows that randomly located particles may converge at a fast speed and lower overshoot by using the proportional-integral-derivative approach, which is a widely used feedback control mechanism. A benchmark consisting of representative training datasets in the domains of function approximations and pattern recognitions is used to evaluate the performance of the proposed PSO. The final outcome confirms the improved performance of the PSO through facilitating the stabilization of PM.