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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Electronics and Telecommunications Research Institute
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Volume & Issues
Volume 29, Issue 6 - Dec 2007
Volume 29, Issue 5 - Oct 2007
Volume 29, Issue 4 - Aug 2007
Volume 29, Issue 3 - Jun 2007
Volume 29, Issue 2 - Apr 2007
Volume 29, Issue 1 - Feb 2007
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A Semantic Service Discovery Network for Large-Scale Ubiquitous Computing Environments
Kang, Sae-Hoon ; Kim, Dae-Woong ; Lee, Young-Hee ; Hyun, Soon-J. ; Lee, Dong-Man ; Lee, Ben ;
ETRI Journal, volume 29, issue 5, 2007, Pages 545~558
This paper presents an efficient semantic service discovery scheme called UbiSearch for a large-scale ubiquitous computing environment. A semantic service discovery network in the semantic vector space is proposed where services that are semantically close to each other are mapped to nearby positions so that the similar services are registered in a cluster of resolvers. Using this mapping technique, the search space for a query is efficiently confined within a minimized cluster region while maintaining high accuracy in comparison to the centralized scheme. The proposed semantic service discovery network provides a number of novel features to evenly distribute service indexes to the resolvers and reduce the number of resolvers to visit. Our simulation study shows that UbiSearch provides good semantic searchability as compared to the centralized indexing system. At the same time, it supports scalable semantic queries with low communication overhead, balanced load distribution among resolvers for service registration and query processing, and personalized semantic matching.
An Adaptive Control for the Propagation Errors Incurred by DCT Coefficient-Dropping Transcoder
Kim, Jin-Soo ; Kim, Jae-Gon ; Seo, Kwang-Deok ; Yun, Mong-Han ;
ETRI Journal, volume 29, issue 5, 2007, Pages 559~568
This paper presents a new distortion control scheme with a simple estimation model for the propagation errors incurred by dropping some parts of the bitstream in a frame dropping-coefficient dropping (FD-CD) transcoder. The primary goal of this paper is to facilitate bit-rate conversions and rate-distortion controls in the compressed domain without introducing a full decoding and reencoding system in the pixel domain. First, the error propagation behavior over several frame sequences due to coefficient dropping is investigated on the basis of statistical and empirical properties. Then, such properties are used to develop a simple estimation model for the CD distortion accounting for the characteristics of the underlying coded-frame. Finally, the proposed estimation model allows us to determine the amount of coefficient dropping and to effectively allocate rate-distortions into coded-frames. Experimental results show that the proposed estimation model accurately describes the characteristics of propagation errors adaptively in the compressed domain and can be easily applied to distortion control over different kinds of video sequences.
Link Error Analysis and Modeling for Video Streaming Cross-Layer Design in Mobile Communication Networks
Karner, Wolfgang ; Nemethova, Olivia ; Svoboda, Philipp ; Rupp, Markus ;
ETRI Journal, volume 29, issue 5, 2007, Pages 569~595
Particularly in wireless communications, link errors severely affect the quality of the services due to the high error probability and the specific error characteristics (burst errors) in the radio access part of the network. In this work, we show that thorough analysis and appropriate modeling of radio-link error behavior are essential to evaluate and optimize higher layer protocols and services. They are also the basis for finding network-aware cross-layer processing algorithms which are capable of exploiting the specific properties of the link error statistics, such as predictability. This document presents the analysis of the radio link errors based on measurements in live Universal Mobile Telecommunication System (UMTS) radio access networks as well as new link error models originating from that analysis. It is shown that the knowledge of the specific link error characteristics leads to significant improvements in the quality of streamed video by applying the proposed novel network- and content-aware cross-layer scheduling algorithms. Although based on live UMTS network experience, many of the conclusions in this work are of general validity and are not limited to UMTS only.
Residual Synchronization Error Elimination in OFDM Baseband Receivers
Hu, Xingbo ; Huang, Yumei ; Hong, Zhiliang ;
ETRI Journal, volume 29, issue 5, 2007, Pages 596~606
It is well known that an OFDM receiver is vulnerable to synchronization errors. Despite fine estimations used in the initial acquisition, there are still residual synchronization errors. Though these errors are very small, they severely degrade the bit error rate (BER) performance. In this paper, we propose a residual error elimination scheme for the digital OFDM baseband receiver aiming to improve the overall BER performance. Three improvements on existing schemes are made: a pilot-aided recursive algorithm for joint estimation of the residual carrier frequency and sampling time offsets; a delay-based timing error correction technique, which smoothly adjusts the incoming data stream without resampling disturbance; and a decision-directed channel gain update algorithm based on recursive least-squares criterion, which offers faster convergence and smaller error than the least-mean-squares algorithms. Simulation results show that the proposed scheme works well in the multipath channel, and its performance is close to that of an OFDM system with perfect synchronization parameters.
A Linear Prediction Based Estimation of Signal-to-Noise Ratio in AWGN Channel
Kamel, Nidal S. ; Jeoti, Varun ;
ETRI Journal, volume 29, issue 5, 2007, Pages 607~613
Most signal-to-noise ratio (SNR) estimation techniques in digital communication channels derive the SNR estimates solely from samples of the received signal after the matched filter. They are based on symbol SNR and assume perfect synchronization and intersymbol interference (ISI)-free symbols. In severe channel distortion where ISI is significant, the performance of these estimators badly deteriorates. We propose an SNR estimator which can operate on data samples collected at the front-end of a receiver or at the input to the decision device. This will relax the restrictions over channel distortions and help extend the application of SNR estimators beyond system monitoring. The proposed estimator uses the characteristics of the second order moments of the additive white Gaussian noise digital communication channel and a linear predictor based on the modified-covariance algorithm in estimating the SNR value. The performance of the proposed technique is investigated and compared with other in-service SNR estimators in digital communication channels. The simulated performance is also compared to the Cram
r-Rao bound as derived at the input of the decision circuit.
Miniaturized Bandstop Filter Using Meander Spurline and Capacitively Loaded Stubs
Liu, Haiwen ; Knoechel, Reinhard H. ; Schuenemann, Klaus F. ;
ETRI Journal, volume 29, issue 5, 2007, Pages 614~618
A miniaturized bandstop filter (BSF) is introduced in this paper. The filter consists of one meander spurline and a pair of capacitively loaded stubs. The meander spurline with low resonant frequency and improved slow-wave factor exhibits excellent resonant bandgap characteristics which can be modeled by a longitudinally coupled resonator. The design of the proposed microstrip BSF is presented, and its performance is measured. Measurements show that there is a stopband from 2.3 to 5.6 GHz with
less than -20 dB. The total length of this BSF equals 23 mm.
Differential Power Analysis on Countermeasures Using Binary Signed Digit Representations
Kim, Tae-Hyun ; Han, Dong-Guk ; Okeya, Katsuyuki ; Lim, Jong-In ;
ETRI Journal, volume 29, issue 5, 2007, Pages 619~632
Side channel attacks are a very serious menace to embedded devices with cryptographic applications. To counteract such attacks many randomization techniques have been proposed. One efficient technique in elliptic curve cryptosystems randomizes addition chains with binary signed digit (BSD) representations of the secret key. However, when such countermeasures have been used alone, most of them have been broken by various simple power analysis attacks. In this paper, we consider combinations which can enhance the security of countermeasures using BSD representations by adding additional countermeasures. First, we propose several ways the improved countermeasures based on BSD representations can be attacked. In an actual statistical power analysis attack, the number of samples plays an important role. Therefore, we estimate the number of samples needed in the proposed attack.
40 Gbps All-Optical 3R Regeneration and Format Conversion with Related InP-Based Semiconductor Devices
Jeon, Min-Yong ; Leem, Young-Ahn ; Kim, Dong-Churl ; Sim, Eun-Deok ; Kim, Sung-Bock ; Ko, Hyun-Sung ; Yee, Dae-Su ; Park, Kyung-Hyun ;
ETRI Journal, volume 29, issue 5, 2007, Pages 633~640
We report an experimental demonstration of 40 Gbps all-optical 3R regeneration with all-optical clock recovery based on InP semiconductor devices. We also obtain alloptical non-return-to-zero to return-to-zero (NRZ-to-RZ) format conversion using the recovered clock signal at 10 Gbps and 40 Gbps. It leads to a good performance using a Mach-Zehnder interferometric wavelength converter and a self-pulsating laser diode (LD). The self-pulsating LD serves a recovered clock, which has an rms timing jitter as low as sub-picosecond. In the case of 3R regeneration of RZ data, we achieve a 1.0 dB power penalty at
BER after demultiplexing 40 Gbps to 10 Gbps with an eletroabsorption modulator. The regenerated 3R data shows stable error-free operation with no BER floor for all channels. The combination of these functional devices provides all-optical 3R regeneration with NRZ-to-RZ conversion.
An Approach for Segmentation of Airborne Laser Point Clouds Utilizing Scan-Line Characteristics
Han, Soo-Hee ; Lee, Jeong-Ho ; Yu, Ki-Yun ;
ETRI Journal, volume 29, issue 5, 2007, Pages 641~648
In this study, we suggest a new segmentation algorithm for processing airborne laser point cloud data which is more memory efficient and faster than previous approaches. The main principle is the reading of data points along a scan line and their direct classification into homogeneous groups as a single process. The results of our experiments demonstrate that the algorithm runs faster and is more memory efficient than previous approaches. Moreover, the segmentation accuracy is generally acceptable.
Improved Viewing Quality of 3-D Images in Computational Integral Imaging Reconstruction Based on Round Mapping Model
Shin, Dong-Hak ; Kim, Nam-Woo ; Yoo, Hoon ; Lee, Joon-Jae ; Lee, Byoung-Ho ; Kim, Eun-Soo ;
ETRI Journal, volume 29, issue 5, 2007, Pages 649~654
In this paper, we propose a computational integral imaging reconstruction (CIIR) method using a round mapping model to improve the viewing quality of 3-D images. The proposed CIIR method can overcome the problem of non-uniformly reconstructed images caused by the conventional method. To show the usefulness of proposed method, some experiments are carried out and the results are presented.
An Efficient Representation of Edge Shapes in Topological Maps
Doh, Nakju Lett ; Chung, Wan-Kyun ;
ETRI Journal, volume 29, issue 5, 2007, Pages 655~666
There are nodes and edges in a topological map. Node data has been used as a main source of information for the localization of mobile robots. In contrast, edge data is regarded as a minor source of information, and it has been used in an intuitive and heuristic way. However, edge data also can be used as a good source of information and provide a way to use edge data efficiently. For that purpose, we define a data format which describes the shape of an edge. This format is called local generalized Voronoi graph's angle (LGA). However, the LGA is constituted of too many samples; therefore, real time localization cannot be performed. To reduce the number of samples, we propose a compression method which utilizes wavelet transformation. This method abstracts the LGA by key factors using far fewer samples than the LGA. Experiments show that the LGA accurately describes the shape of the edges and that the key factors preserve most information of the LGA while reducing the number of samples.
A Temperature-Controllable Microelectrode and Its Application to Protein Immobilization
Lee, Dae-Sik ; Choi, Hyoung-Gil ; Chung, Kwang-Hyo ; Lee, Bun-Yeoul ; Pyo, Hyeon-Bong ; Yoon, Hyun-C. ;
ETRI Journal, volume 29, issue 5, 2007, Pages 667~669
This letter presents a smart integrated microfluidic device which can be applied to actively immobilize proteins on demand. The active component in the device is a temperature-controllable microelectrode array with a smart polymer film, poly(N-isopropylacrylamide) (PNIPAAm) which can be thermally switched between hydrophilic and hydrophobic states. It is integrated into a micro hot diaphragm having an integrated micro heater and temperature sensors on a 2-micrometer-thick silicon oxide/silicon nitride/silicon oxide (O/N/O) template. Only 36 mW is required to heat the large template area of 2 mm
16 mm to
within 1 second. To relay the stimulus-response activity to the microelectrode surface, the interface is modified with a smart polymer. For a model biomolecular affinity test, an anti-6-(2, 4-dinitrophenyl) aminohexanoic acid (DNP) antibody protein immobilization on the microelectrodes is demonstrated by fluorescence patterns.
High-Gain Wideband CMOS Low Noise Amplifier with Two-Stage Cascode and Simplified Chebyshev Filter
Kim, Sung-Soo ; Lee, Young-Sop ; Yun, Tae-Yeoul ;
ETRI Journal, volume 29, issue 5, 2007, Pages 670~672
An ultra-wideband low-noise amplifier is proposed with operation up to 8.2 GHz. The amplifier is fabricated with a 0.18-
CMOS process and adopts a two-stage cascode architecture and a simplified Chebyshev filter for high gain, wide band, input-impedance matching, and low noise. The gain of 19.2 dB and minimum noise figure of 3.3 dB are measured over 3.4 to 8.2 GHz while consuming 17.3 mW of power. The Proposed UWB LNA achieves a measured power-gain bandwidth product of 399.4 GHz.
A 60 GHz Medium Power Amplifier for Radio-over-Fiber System
Chang, Woo-Jin ; Oh, Seung-Hyeub ; Kim, Hae-Choen ;
ETRI Journal, volume 29, issue 5, 2007, Pages 673~675
We present the design and fabrication of a 60 GHz medium power amplifier monolithic microwave integrated circuit with excellent gain-flatness for a 60 GHz radio-over-fiber system. The circuit has a 4-stage structure using microstrip coupled lines instead of metal-insulator-metal capacitors for unconditional stability of the amplifier and yield enhancement. The gains of each stage of the amplifier are modified to provide broadband characteristics of input/output matching for the first and fourth stages and to achieve higher gains for the second and third stages to improve the gain-flatness of the amplifier for wideband.
Chirp-Based Cognitive Ultra-wideband Radio
Shen, Hanbing ; Zhang, Weihua ; Kwak, Kyung-Sup ;
ETRI Journal, volume 29, issue 5, 2007, Pages 676~678
In this letter, we propose a cognitive ultra-wideband radio scheme which is based on a modified chirp waveform. Therefore, it requires only time domain processing in the cognitive radio systems and reduces system complexity and power consumption.
Feed-Forward Control of Transient Gain Dynamics of an EDFA for Optical Burst Networks
Cho, Jeong-Sik ; Cho, Min-Jae ; Won, Yong-Hyub ;
ETRI Journal, volume 29, issue 5, 2007, Pages 679~681
In this letter, we demonstrate a technique for suppression of transients in output bursts of an erbium-doped fiber amplifier (EDFA) in an optical burst network. To suppress the transients, the EDFA is forward-fed by non-fluctuating input utilizing a power-modulated burst control packet channel. Using the technique, we obtained a maximum 1.7 dB reduction in gain transient in the EDFA output, and we transmitted 9.953 Gbps data bursts and 2.488 Gbps burst control packets stably.
Pre-reservation of Resources and Controlled Loops for Contention Resolution in OBS Networks
Comellas, Jaume ; Conesa, Josep ; Padaro, Salvatore ; Junyent, Gabriel ;
ETRI Journal, volume 29, issue 5, 2007, Pages 682~684
A new scheme to alleviate contention in optical burst switching networks is proposed. It consists of preventively reserving resources in a node, to be used if resources are busy on the next hop node. The burst is sent back to the preceding node and then resent forward. Simulations are carried out to assess the feasibility of the proposed scheme. Its performance is compared with that of contention resolution based on deflection routing.
An Online Buffer Management Algorithm for QoS-Sensitive Multimedia Networks
Kim, Sung-Wook ; Kim, Sung-Chun ;
ETRI Journal, volume 29, issue 5, 2007, Pages 685~687
In this letter, we propose a new online buffer management algorithm to simultaneously provide diverse multimedia traffic services and enhance network performance. Our online approach exhibits dynamic adaptability and responsiveness to the current traffic conditions in multimedia networks. This approach can provide high buffer utilization and thereby improve packet loss performance at the time of congestion.
Multi-model Switching for Car Navigation Containing Low-Grade IMU and GPS Receiver
Cho, Seong-Yun ; Kim, Byung-Doo ; Cho, Young-Su ; Choi, Wan-Sik ;
ETRI Journal, volume 29, issue 5, 2007, Pages 688~690
This letter presents a filter for a car navigation system integrating a low-grade inertial measurements unit (IMU) and a global positioning system receiver. The filter is designed according to the state variables to be estimated and the usable measurements. The usable measurements change from case to case, and the estimative state variables also change due to the measurements; therefore, multiple models must be used for real environmental maneuvers. In this letter, four models for land navigation are chosen and switched by rearranging the system matrix and resetting the error covariance matrices.
An Efficient PAB-Based Query Indexing for Processing Continuous Queries on Moving Objects
Jang, Su-Min ; Song, Seok-Il ; Yoo, Jae-Soo ;
ETRI Journal, volume 29, issue 5, 2007, Pages 691~693
Existing methods to process continuous range queries are not scalable. In particular, as the number of continuous range queries on a large number of moving objects becomes larger, their performance degrades significantly. We propose a novel query indexing method called the projected attribute bit (PAB)-based query index. We project a two-dimensional continuous range query on each axis to get two one-dimensional bit lists. Since the queries are transformed to bit lists and query evaluation is performed by bit operations, the storage cost of indexing and query evaluation time are reduced significantly. Through various experiments, we show that our method outperforms the containment-encoded squares-based indexing method, which is one of the most recently proposed methods.
Adaptive Coefficient Scanning Based on the Intra Prediction Mode
Choi, Byeong-Doo ; Kim, Jin-Hyung ; Ko, Sung-Jea ;
ETRI Journal, volume 29, issue 5, 2007, Pages 694~696
This letter presents an adaptive coefficient scanning method for intra mode coding in H.264. The proposed adaptive scanning uses six alternative scanning orders based on the intra prediction mode. Experimental results show that the proposed method improves the coding efficiency up to 3% compared to conventional scanning methods without additional computations.
Spatial Histograms for Region-Based Tracking
Birchfield, Stanley T. ; Rangarajan, Sriram ;
ETRI Journal, volume 29, issue 5, 2007, Pages 697~699
Spatiograms are histograms augmented with spatial means and covariances to capture a richer description of the target. We present a particle filtering framework for region-based tracking using spatiograms. Unlike mean shift, the framework allows for non-differentiable similarity measures to compare two spatiograms; we present one such similarity measure, a combination of a recent weighting scheme and histogram intersection. Experimental results show improved performance with the new measure as well as the importance of global spatial information for tracking. The performance of spatiograms is compared with color histograms and several texture histogram methods.
Support Vector Machine Learning for Region-Based Image Retrieval with Relevance Feedback
Kim, Deok-Hwan ; Song, Jae-Won ; Lee, Ju-Hong ; Choi, Bum-Ghi ;
ETRI Journal, volume 29, issue 5, 2007, Pages 700~702
We present a relevance feedback approach based on multi-class support vector machine (SVM) learning and cluster-merging which can significantly improve the retrieval performance in region-based image retrieval. Semantically relevant images may exhibit various visual characteristics and may be scattered in several classes in the feature space due to the semantic gap between low-level features and high-level semantics in the user's mind. To find the semantic classes through relevance feedback, the proposed method reduces the burden of completely re-clustering the classes at iterations and classifies multiple classes. Experimental results show that the proposed method is more effective and efficient than the two-class SVM and multi-class relevance feedback methods.
Image Fidelity Assessment Using the Edge Histogram Descriptor of MPEG-7
Won, Chee-Sun ;
ETRI Journal, volume 29, issue 5, 2007, Pages 703~705
An image fidelity assessment using the edge histogram descriptor (EHD) of MPEG-7 is presented. Neither additional data nor fragile watermarking is needed, and there is no need to access the original image as a reference. Only the EHDs of the original image and the received image are required. The peak signal-to-noise ratio (PSNR) obtained by comparing the EHD extracted from the received image and that of the original image is used to assess the noise level of the received image. Experimental results show that the PSNRs calculated from the conventional pixel-to-pixel gray level and from the proposed bin-to-bin EHD maintain a proportional relationship. This implies that the EHD can be used instead of image data for the image fidelity assessments.