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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 36, Issue 6 - Dec 2014
Volume 36, Issue 5 - Oct 2014
Volume 36, Issue 4 - Aug 2014
Volume 36, Issue 3 - Jun 2014
Volume 36, Issue 2 - Apr 2014
Volume 36, Issue 1 - Feb 2014
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Robust Sign Recognition System at Subway Stations Using Verification Knowledge
Lee, Dongjin ; Yoon, Hosub ; Chung, Myung-Ae ; Kim, Jaehong ;
ETRI Journal, volume 36, issue 5, 2014, Pages 696~703
DOI : 10.4218/etrij.14.2214.0007
In this paper, we present a walking guidance system for the visually impaired for use at subway stations. This system, which is based on environmental knowledge, automatically detects and recognizes both exit numbers and arrow signs from natural outdoor scenes. The visually impaired can, therefore, utilize the system to find their own way (for example, using exit numbers and the directions provided) through a subway station. The proposed walking guidance system consists mainly of three stages: (a) sign detection using the MCT-based AdaBoost technique, (b) sign recognition using support vector machines and hidden Markov models, and (c) three verification techniques to discriminate between signs and non-signs. The experimental results indicate that our sign recognition system has a high performance with a detection rate of 98%, a recognition rate of 99.5%, and a false-positive error rate of 0.152.
Consolidation of Subtasks for Target Task in Pipelined NLP Model
Son, Jeong-Woo ; Yoon, Heegeun ; Park, Seong-Bae ; Cho, Keeseong ; Ryu, Won ;
ETRI Journal, volume 36, issue 5, 2014, Pages 704~713
DOI : 10.4218/etrij.14.2214.0035
Most natural language processing tasks depend on the outputs of some other tasks. Thus, they involve other tasks as subtasks. The main problem of this type of pipelined model is that the optimality of the subtasks that are trained with their own data is not guaranteed in the final target task, since the subtasks are not optimized with respect to the target task. As a solution to this problem, this paper proposes a consolidation of subtasks for a target task (
, all parameters of a target task and its subtasks are optimized to fulfill the objective of the target task.
finds such optimized parameters through a backpropagation algorithm. In experiments in which text chunking is a target task and part-of-speech tagging is its subtask,
outperforms a traditional pipelined text chunker. The experimental results prove the effectiveness of optimizing subtasks with respect to the target task.
Weighted Finite State Transducer-Based Endpoint Detection Using Probabilistic Decision Logic
Chung, Hoon ; Lee, Sung Joo ; Lee, Yun Keun ;
ETRI Journal, volume 36, issue 5, 2014, Pages 714~720
DOI : 10.4218/etrij.14.2214.0030
In this paper, we propose the use of data-driven probabilistic utterance-level decision logic to improve Weighted Finite State Transducer (WFST)-based endpoint detection. In general, endpoint detection is dealt with using two cascaded decision processes. The first process is frame-level speech/non-speech classification based on statistical hypothesis testing, and the second process is a heuristic-knowledge-based utterance-level speech boundary decision. To handle these two processes within a unified framework, we propose a WFST-based approach. However, a WFST-based approach has the same limitations as conventional approaches in that the utterance-level decision is based on heuristic knowledge and the decision parameters are tuned sequentially. Therefore, to obtain decision knowledge from a speech corpus and optimize the parameters at the same time, we propose the use of data-driven probabilistic utterance-level decision logic. The proposed method reduces the average detection failure rate by about 14% for various noisy-speech corpora collected for an endpoint detection evaluation.
Speech Enhancement Using Phase-Dependent A Priori SNR Estimator in Log-Mel Spectral Domain
Lee, Yun-Kyung ; Park, Jeon Gue ; Lee, Yun Keun ; Kwon, Oh-Wook ;
ETRI Journal, volume 36, issue 5, 2014, Pages 721~729
DOI : 10.4218/etrij.14.2214.0039
We propose a novel phase-based method for single-channel speech enhancement to extract and enhance the desired signals in noisy environments by utilizing the phase information. In the method, a phase-dependent a priori signal-to-noise ratio (SNR) is estimated in the log-mel spectral domain to utilize both the magnitude and phase information of input speech signals. The phase-dependent estimator is incorporated into the conventional magnitude-based decision-directed approach that recursively computes the a priori SNR from noisy speech. Additionally, we reduce the performance degradation owing to the one-frame delay of the estimated phase-dependent a priori SNR by using a minimum mean square error (MMSE)-based and maximum a posteriori (MAP)-based estimator. In our speech enhancement experiments, the proposed phase-dependent a priori SNR estimator is shown to improve the output SNR by 2.6 dB for both the MMSE-based and MAP-based estimator cases as compared to a conventional magnitude-based estimator.
Personalized Healthcare System for Chronic Disease Care in Cloud Environment
Jeong, Sangjin ; Kim, Yong-Woon ; Youn, Chan-Hyun ;
ETRI Journal, volume 36, issue 5, 2014, Pages 730~740
DOI : 10.4218/etrij.14.2214.0070
The rapid increase in the number of patients with chronic diseases is an important public healthcare issue in many countries, which accelerates many studies on a healthcare system that can, whenever and wherever, extract and process patient data. A patient with a chronic disease conducts self-management in an out-of-hospital environment, particularly in an at-home environment, so it is important to provide integrated and personalized healthcare services for effective care. To help provide effective care for chronic disease patients, we propose a service flow and a new cloud-based personalized healthcare system architecture supporting both at-home and at-hospital environments. The system considers the different characteristics of at-hospital and at-home environments, and it provides various chronic disease care services. A prototype implementation and a predicted cost model are provided to show the effectiveness of the system. The proposed personalized healthcare system can support cost-effective disease care in an at-hospital environment and personalized self-management of chronic disease in an at-home environment.
Symbiotic Dynamic Memory Balancing for Virtual Machines in Smart TV Systems
Kim, Junghoon ; Kim, Taehun ; Min, Changwoo ; Jun, Hyung Kook ; Lee, Soo Hyung ; Kim, Won-Tae ; Eom, Young Ik ;
ETRI Journal, volume 36, issue 5, 2014, Pages 741~751
DOI : 10.4218/etrij.14.2214.0038
Smart TV is expected to bring cloud services based on virtualization technologies to the home environment with hardware and software support. Although most physical resources can be shared among virtual machines (VMs) using a time sharing approach, allocating the proper amount of memory to VMs is still challenging. In this paper, we propose a novel mechanism to dynamically balance the memory allocation among VMs in virtualized Smart TV systems. In contrast to previous studies, where a virtual machine monitor (VMM) is solely responsible for estimating the working set size, our mechanism is symbiotic. Each VM periodically reports its memory usage pattern to the VMM. The VMM then predicts the future memory demand of each VM and rebalances the memory allocation among the VMs when necessary. Experimental results show that our mechanism improves performance by up to 18.28 times and reduces expensive memory swapping by up to 99.73% with negligible overheads (0.05% on average).
Quality Enhancement for Hybrid 3DTV with Mixed Resolution Using Conditional Replenishment Algorithm
Jung, Kyeong-Hoon ; Bang, Min-Suk ; Kim, Sung-Hoon ; Choo, Hyon-Gon ; Kang, Dong-Wook ;
ETRI Journal, volume 36, issue 5, 2014, Pages 752~760
DOI : 10.4218/etrij.14.0113.1092
This paper proposes a conditional replenishment algorithm (CRA) to improve the visual quality (where spatial resolutions of the left and right views are mismatched) of a hybrid stereoscopic 3DTV that is based on the ATSC-M/H standard. So as to generate an enhanced view, the CRA is to choose the better substitute among a disparity-compensated view with high quality and a simply interpolated view. The CRA generates a disparity map that includes modes and disparity vectors as additional information. It also employs a quad-tree structure with variable block size by considering the spatial correlation of disparity vectors. In addition, it takes advantage of the disparity map used in a previous frame to keep the amount of additional information as small as possible. The simulation results show that the proposed CRA can successfully improve the peak signal-to-noise ratio of a poor-quality view and consequently have a positive effect on the subjective quality of the resulting 3D view.
Congestion-Aware Handover in LTE Systems for Load Balancing in Transport Network
Marwat, Safdar Nawaz Khan ; Meyer, Sven ; Weerawardane, Thushara ; Goerg, Carmelita ;
ETRI Journal, volume 36, issue 5, 2014, Pages 761~771
DOI : 10.4218/etrij.14.0113.1034
Long-Term Evolution employs a hard handover procedure. To reduce the interruption of data flow, downlink data is forwarded from the serving eNodeB (eNB) to the target eNB during handover. In cellular networks, unbalanced loads may lead to congestion in both the radio network and the backhaul network, resulting in bad end-to-end performance as well as causing unfairness among the users sharing the bottleneck link. This work focuses on congestion in the transport network. Handovers toward less loaded cells can help redistribute the load of the bottleneck link; such a mechanism is known as load balancing. The results show that the introduction of such a handover mechanism into the simulation environment positively influences the system performance. This is because terminals spend more time in the cell; hence, a better reception is offered. The utilization of load balancing can be used to further improve the performance of cellular systems that are experiencing congestion on a bottleneck link due to an uneven load.
Two-Microphone Binary Mask Speech Enhancement in Diffuse and Directional Noise Fields
Abdipour, Roohollah ; Akbari, Ahmad ; Rahmani, Mohsen ;
ETRI Journal, volume 36, issue 5, 2014, Pages 772~782
DOI : 10.4218/etrij.14.0113.0917
Two-microphone binary mask speech enhancement (2mBMSE) has been of particular interest in recent literature and has shown promising results. Current 2mBMSE systems rely on spatial cues of speech and noise sources. Although these cues are helpful for directional noise sources, they lose their efficiency in diffuse noise fields. We propose a new system that is effective in both directional and diffuse noise conditions. The system exploits two features. The first determines whether a given time-frequency (T-F) unit of the input spectrum is dominated by a diffuse or directional source. A diffuse signal is certainly a noise signal, but a directional signal could correspond to a noise or speech source. The second feature discriminates between T-F units dominated by speech or directional noise signals. Speech enhancement is performed using a binary mask, calculated based on the proposed features. In both directional and diffuse noise fields, the proposed system segregates speech T-F units with hit rates above 85%. It outperforms previous solutions in terms of signal-to-noise ratio and perceptual evaluation of speech quality improvement, especially in diffuse noise conditions.
Inter-carrier Interference Reduction Scheme for SFBC-OFDM Systems
Kim, Kyung-Hwa ; Seo, Bangwon ;
ETRI Journal, volume 36, issue 5, 2014, Pages 783~790
DOI : 10.4218/etrij.14.0113.0711
In this paper, we first analyze carrier-to-interference ratio performance of the space-frequency block coded orthogonal frequency-division multiplexing (SFBC-OFDM) system in the presence of phase noise (PHN) and residual carrier frequency offset (RCFO). From the analysis, we observe that conventional SFBC-OFDM systems suffer severely in the presence of PHN and RCFO. Therefore, we propose a new inter-carrier interference (ICI) self-cancellation method - namely, ISC - for SFBC-OFDM systems to reduce the ICI caused by PHN and RCFO. Through the simulation results, we show that the proposed scheme compensates the ICI caused by PHN and RCFO in Alamouti SFBC-OFDM systems and has a better performance than conventional schemes.
Novel Hybrid Content Synchronization Scheme for Augmented Broadcasting Services
Kim, Soonchoul ; Choi, Bumsuk ; Jeong, Youngho ; Hong, Jinwoo ; Kim, Kyuheon ;
ETRI Journal, volume 36, issue 5, 2014, Pages 791~798
DOI : 10.4218/etrij.14.0114.0346
As a new hybrid broadcasting service, augmented broadcasting shows enhanced broadcasting content on a large TV screen, while augmented reality (AR) on a mobile device augments additional graphical content onto an input image from the device's own camera to provide useful and convenient information for users. A one-sided broadcasting service using AR has already been attempted in virtual advertisements during sport broadcasts. However, because its augmentation is preprocessed before the video image is transmitted, the viewer at home may have no influence on this formation; and no interaction for the user is possible unless the viewer has a direct connection to the content provider. Augmented broadcasting technology enables viewers to watch mixed broadcasting content only when they want such service and to watch original broadcasting content when they do not. To realize an augmented broadcasting service, the most important issue is to resolve the hybrid content synchronization over heterogeneous broadcast and broadband networks. This paper proposes a novel hybrid content synchronization scheme for an augmented broadcasting service and presents its implementation and results in a terrestrial DTV environment.
Rake-Based Cellular Radar Receiver Design for Moving Target Detection in Multipath Channel
Kim, Yeejung ; Jeong, Myungdeuk ; Han, Youngnam ;
ETRI Journal, volume 36, issue 5, 2014, Pages 799~807
DOI : 10.4218/etrij.14.0113.0702
In this paper, we design a rake-based cellular radar receiver (CRR) scheme to detect a moving target located in a multipath environment. The modules of Doppler filter banks, threshold level test, and target detection module are newly introduced into the conventional rake receiver so that it can function as a radar system. The proposed CRR tests the Doppler-shift frequency and signal-to-noise ratio of the received signal against predefined threshold levels to determine detection and then calculates target velocities and ranges. The system performance is evaluated in terms of detection probability and the maximum detection range under a Nakagami-n channel that reflects the multipath environment.
Simultaneous Information and Power Transfer Using Magnetic Resonance
Lee, Kisong ; Cho, Dong-Ho ;
ETRI Journal, volume 36, issue 5, 2014, Pages 808~818
DOI : 10.4218/etrij.14.0114.0161
To deal with the major challenges of embedded sensor networks, we consider the use of magnetic fields as a means of reliably transferring both information and power to embedded sensors. We focus on a power allocation strategy for an orthogonal frequency-division multiplexing system to maximize the transferred power under the required information capacity and total available power constraints. First, we consider the case of a co-receiver, where information and power can be extracted from the same signal. In this case, we find an optimal power allocation (OPA) and provide the upper bound of achievable transferred power and capacity pairs. However, the exact calculation of the OPA is computationally complex. Thus, we propose a low-complexity power reallocation algorithm. For practical consideration, we consider the case of a separated receiver (where information and power are transferred separately through different resources) and propose two heuristic power allocation algorithms. Through simulations using the Agilent Advanced Design System and Ansoft High Frequency Structure Simulator, we validate the magnetic-inductive channel characteristic. In addition, we show the performances of the proposed algorithms by providing achievable
Popularity-Based Adaptive Content Delivery Scheme with In-Network Caching
Kim, Jeong Yun ; Lee, Gyu Myoung ; Choi, Jun Kyun ;
ETRI Journal, volume 36, issue 5, 2014, Pages 819~828
DOI : 10.4218/etrij.14.0113.0090
To solve the increasing popularity of video streaming services over the Internet, recent research activities have addressed the locality of content delivery from a network edge by introducing a storage module into a router. To employ in-network caching and persistent request routing, this paper introduces a hybrid content delivery network (CDN) system combining novel content routers in an underlay together with a traditional CDN server in an overlay. This system first selects the most suitable delivery scheme (that is, multicast or broadcast) for the content in question and then allocates an appropriate number of channels based on a consideration of the content's popularity. The proposed scheme aims to minimize traffic volume and achieve optimal delivery cost, since the most popular content is delivered through broadcast channels and the least popular through multicast channels. The performance of the adaptive scheme is clearly evaluated and compared against both the multicast and broadcast schemes in terms of the optimal in-network caching size and number of unicast channels in a content router to observe the significant impact of our proposed scheme.
Extended Trench Gate Superjunction Lateral Power MOSFET for Ultra-Low Specific on-Resistance and High Breakdown Voltage
Cho, Doohyung ; Kim, Kwangsoo ;
ETRI Journal, volume 36, issue 5, 2014, Pages 829~834
DOI : 10.4218/etrij.14.0113.0826
In this paper, a lateral power metal-oxide-semiconductor field-effect transistor with ultra-low specific on-resistance is proposed to be applied to a high-voltage (up to 200 V) integrated chip. The proposed structure has two characteristics. Firstly, a high level of drift doping concentration can be kept because a tilt-implanted p-drift layer assists in the full depletion of the n-drift region. Secondly, charge imbalance is avoided by an extended trench gate, which suppresses the trench corner effect occurring in the n-drift region and helps achieve a high breakdown voltage (BV). Compared to a conventional trench gate, the simulation result shows a 37.5% decrease in
and a 16% improvement in BV.
Non-resonant Element in Slotted Ground Plane for Multiband Antenna Operation
Picher, Cristina ; Anguera, Jaume ; Andujar, Aurora ; Bujalance, Adrian ;
ETRI Journal, volume 36, issue 5, 2014, Pages 835~840
DOI : 10.4218/etrij.14.0113.1345
New ways of achieving small, multiband, multifunctional, and standard solutions for mobile handset antennas are demanded in the current wireless market. A non-resonant element of
, a matching network, and a
slotted ground plane are proposed to satisfy mobile market demands that require multiband operation and small antenna solutions. The main advantage of the proposed design is that with only one non-resonant element of considerably small size (
, 900 MHz), the handset is capable of providing operation at mobile bands.
Design and Analysis of Refractometer Based on Bend Waveguide Structure with Air Trench for Optical Sensor Applications
Ryu, Jin Hwa ; Lee, Woo-Jin ; Lee, Bong Kuk ; Do, Lee-Mi ; Lee, Kang Bok ; Um, Namkyoung ; Baek, Kyu-Ha ;
ETRI Journal, volume 36, issue 5, 2014, Pages 841~846
DOI : 10.4218/etrij.14.0114.0413
This study proposes a novel optical sensor structure based on a refractometer combining a bend waveguide with an air trench. The optical sensor is a
splitter structure with a reference channel and a sensing channel. The reference channel has a straight waveguide. The sensing channel consists of a U-bend waveguide connecting four C-bends, and a trench structure to partially expose the core layer. The U-bend waveguide consists of one C-bend with the maximum optical loss and three C-bends with minimum losses. A trench provides a quantitative measurement environment and is aligned with the sidewall of the C-bend having the maximum loss. The intensity of the output power depends on the change in the refractive index of the measured material. The insertion loss of the proposed optical sensor changes from 3.7 dB to 59.1 dB when the refractive index changes from 1.3852 to 1.4452.
Surface Control of Planarization Layer on Embossed Glass for Light Extraction in OLEDs
Cho, Doo-Hee ; Shin, Jin-Wook ; Moon, Jaehyun ; Park, Seung Koo ; Joo, Chul Woong ; Cho, Nam Sung ; Huh, Jin Woo ; Han, Jun-Han ; Lee, Jonghee ; Chu, Hye Yong ; Lee, Jeong-Ik ;
ETRI Journal, volume 36, issue 5, 2014, Pages 847~855
DOI : 10.4218/etrij.14.0113.0845
We developed a highly refractive index planarization layer showing a very smooth surface for organic light-emitting diode (OLED) light extraction, and we successfully prepared a highly efficient white OLED device with an embossed nano-structure and highly refractive index planarization layers. White OLEDs act as an internal out-coupling layer. We used a spin-coating method and two types of
solutions for a planarization of the embossed nano-structure on a glass substrate. The first
sol, which consists of
colloidal particles in an acidic aqueous solution and several organic additives. The second solution was an organic and inorganic hybrid solution of
. The surface roughness (
) and refractive index of the
planarization films on a flat glass were 0.4 nm and 2.0 at 550 nm, respectively. The J-V characteristics of the OLED including the embossed nano-structure and the
planarization film were almost the same as those of an OLED with a flat glass, and the luminous efficacy of the aforementioned OLED was enhanced by 34% compared to that of an OLED with a flat glass.
Relations among Security Models for Authenticated Key Exchange
Kwon, Jeong Ok ; Jeong, Ik Rae ;
ETRI Journal, volume 36, issue 5, 2014, Pages 856~864
DOI : 10.4218/etrij.14.0113.1071
Usually, key-establishment protocols are suggested in a security model. However, there exist several different security models in the literature defined by their respective security notions. In this paper, we study the relations between the security models of key establishment. For the chosen security models, we first show that some proven key-establishment protocols are not secure in the more restricted security models. We then suggest two compilers by which we can convert a key-establishment protocol that is secure in a specific security model into a key-establishment protocol that is still secure in a more restricted security model.
iVisher: Real-Time Detection of Caller ID Spoofing
Song, Jaeseung ; Kim, Hyoungshick ; Gkelias, Athanasios ;
ETRI Journal, volume 36, issue 5, 2014, Pages 865~875
DOI : 10.4218/etrij.14.0113.0798
Voice phishing (vishing) uses social engineering, based on people's trust in telephone services, to trick people into divulging financial data or transferring money to a scammer. In a vishing attack, a scammer often modifies the telephone number that appears on the victim's phone to mislead the victim into believing that the phone call is coming from a trusted source, since people typically judge a caller's legitimacy by the displayed phone number. We propose a system named iVisher for detecting a concealed incoming number (that is, caller ID) in Session Initiation Protocol-based Voice-over-Internet Protocol initiated phone calls. Our results demonstrate that iVisher is capable of detecting a concealed caller ID without significantly impacting upon the overall call setup time.
Program Cache Busy Time Control Method for Reducing Peak Current Consumption of NAND Flash Memory in SSD Applications
Park, Se-Chun ; Kim, You-Sung ; Cho, Ho-Youb ; Choi, Sung-Dae ; Yoon, Mi-Sun ; Kim, Tae-Yun ; Park, Kun-Woo ; Park, Jongsun ; Kim, Soo-Won ;
ETRI Journal, volume 36, issue 5, 2014, Pages 876~879
DOI : 10.4218/etrij.14.0213.0537
In current NAND flash design, one of the most challenging issues is reducing peak current consumption (peak ICC), as it leads to peak power drop, which can cause malfunctions in NAND flash memory. This paper presents an efficient approach for reducing the peak ICC of the cache program in NAND flash memory - namely, a program Cache Busy Time (tPCBSY) control method. The proposed tPCBSY control method is based on the interesting observation that the array program current (ICC2) is mainly decided by the bit-line bias condition. In the proposed approach, when peak ICC2 becomes larger than a threshold value, which is determined by a cache loop number, cache data cannot be loaded to the cache buffer (CB). On the other hand, when peak ICC2 is smaller than the threshold level, cache data can be loaded to the CB. As a result, the peak ICC of the cache program is reduced by 32% at the least significant bit page and by 15% at the most significant bit page. In addition, the program throughput reaches 20 MB/s in multiplane cache program operation, without restrictions caused by a drop in peak power due to cache program operations in a solid-state drive.