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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 37, Issue 6 - Dec 2015
Volume 37, Issue 5 - Oct 2015
Volume 37, Issue 4 - Aug 2015
Volume 37, Issue 3 - May 2015
Volume 37, Issue 2 - Apr 2015
Volume 37, Issue 1 - Feb 2015
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Analysis on Co-channel Interference of Human Body Communication Supporting IEEE 802.15.6 BAN Standard
Hwang, Jung-Hwan ; Kang, Tae-Wook ; Kim, Youn-Tae ; Park, Seong-Ook ;
ETRI Journal, volume 37, issue 3, 2015, Pages 439~449
DOI : 10.4218/etrij.15.0114.1029
Human body communication (HBC) is being recognized as a new communication technology for mobile and wearable devices in a body area network (BAN). This paper presents co-channel interference experienced by HBC supporting the physical layer in the IEEE 802.15.6 BAN standard. To analyze the co-channel interference, a co-channel interference model is introduced, and space-domain and time-domain parameters representing an interference environment are generated using the co-channel interference model. A new signal-to-interference ratio (SIR) parameter depending on the peak amplitudes of the data signals causing co-channel interference is defined; co-channel interference can be easily analyzed and modelled using the newly defined SIR. The BER degradation model derived using the co-channel interference model and SIR in this paper can be effectively used to estimate the performance.
Coverage and Energy Modeling of HetNet Under Base Station On-Off Model
Song, Sida ; Chang, Yongyu ; Wang, Xianling ; Yang, Dacheng ;
ETRI Journal, volume 37, issue 3, 2015, Pages 450~459
DOI : 10.4218/etrij.15.0114.0669
Small cell networks, as an important evolution path for next-generation cellular networks, have drawn much attention. Different from the traditional base stations (BSs) always-on model, we proposed a BSs on-off model, where a new, simple expression for the probabilities of active BSs in a heterogeneous network is derived. This model is more suitable for application in practical networks. Based on this, we develop an analytical framework for the performance evaluation of small cell networks, adopting stochastic geometry theory. We derive the system coverage probability; average energy efficiency (AEE) and average uplink power consumption (AUPC) for different association strategies; maximum biased received power (MaBRP); and minimum association distance (MiAD). It is analytically shown that MaBRP is beneficial for coverage but will have some loss in energy saving. On the contrary, MiAD is not advocated from the point of coverage but is more energy efficient. The simulation results show that the use of range expansion in MaBRP helps to save energy but that this is not so in MiAD. Furthermore, we can achieve an optimal AEE by establishing an appropriate density of small cells.
Outage Analysis of OFDM-Based Cognitive AF Relay Network in the Presence of Narrowband Interference
Rajkumar, Samikkannu ; Senthilkumaran, V.N. ; Thiruvengadam, S.J. ;
ETRI Journal, volume 37, issue 3, 2015, Pages 460~470
DOI : 10.4218/etrij.15.0114.0300
Orthogonal frequency-division multiplexing (OFDM) is one of the most widely used technologies in current wireless communication systems and standards. Cognitive radio (CR) provides a robust solution to the problem of spectrum congestion as it offers opportunistic usage of frequency bands that are not occupied by primary users. Due to the underlying sensing, spectrum shaping, scaling, and interoperable capabilities of OFDM, it has been adapted as a best transmission technology for CR wireless systems. However, the performance of an OFDM-based CR wireless system is affected by the existence of narrowband interference (NBI) from other users. Further, due to carrier frequency offset in NBI sources, NBI energy may spread over all subcarriers of an OFDM signal. In this paper, a fixed Amplify-and-Forward (AF) relay that operates at a frequency band that is different from that of direct mode is introduced to suppress the effect of NBI. Analytical expressions are derived for outage probability in direct, AF-relay, and incremental relaying modes. The outage performance of the proposed AF relay-based CR network is proven to be better than that of direct mode.
Energy-Efficient Power Allocation for Cognitive Radio Networks with Joint Overlay and Underlay Spectrum Access Mechanism
Zuo, Jiakuo ; Zhao, Li ; Bao, Yongqiang ; Zou, Cairong ;
ETRI Journal, volume 37, issue 3, 2015, Pages 471~479
DOI : 10.4218/etrij.15.0114.0739
Traditional designs of cognitive radio (CR) focus on maximizing system throughput. In this paper, we study the joint overlay and underlay power allocation problem for orthogonal frequency-division multiple access-based CR. Instead of maximizing system throughput, we aim to maximize system energy efficiency (EE), measured by a "bit per Joule" metric, while maintaining the minimal rate requirement of a given CR system, under the total power constraint of a secondary user and interference constraints of primary users. The formulated energy-efficient power allocation (EEPA) problem is nonconvex; to make it solvable, we first transform the original problem into a convex optimization problem via fractional programming, and then the Lagrange dual decomposition method is used to solve the equivalent convex optimization problem. Finally, an optimal EEPA allocation scheme is proposed. Numerical results show that the proposed method can achieve better EE performance.
Energy-Efficient Quorum-Based MAC Protocol for Wireless Sensor Networks
Annabel, L. Sherly Puspha ; Murugan, K. ;
ETRI Journal, volume 37, issue 3, 2015, Pages 480~490
DOI : 10.4218/etrij.15.0114.0688
The reliability of sensor networks is generally dependent on the battery power of the sensor nodes that it employs; hence it is crucial for the sensor nodes to efficiently use their battery resources. This research paper presents a method to increase the reliability of sensor nodes by constructing a connected dominating tree (CDT), which is a subnetwork of wireless sensor networks. It detects the minimum number of dominatees, dominators, forwarder sensor nodes, and aggregates, as well as transmitting data to the sink. A new medium access control (MAC) protocol, called Homogenous Quorum-Based Medium Access Control (HQMAC), is also introduced, which is an adaptive, homogenous, asynchronous quorum-based MAC protocol. In this protocol, certain sensor nodes belonging to a network will be allowed to tune their wake-up and sleep intervals, based on their own traffic load. A new quorum system, named BiQuorum, is used by HQMAC to provide a low duty cycle, low network sensibility, and a high number of rendezvous points when compared with other quorum systems such as grid and dygrid. Both the theoretical results and the simulation results proved that the proposed HQMAC (when applied to a CDT) facilitates low transmission latency, high delivery ratio, and low energy consumption, thus extending the lifetime of the network it serves.
Fast Spectrum Sensing with Coordinate System in Cognitive Radio Networks
Lee, Wilaiporn ; Srisomboon, Kanabadee ; Prayote, Akara ;
ETRI Journal, volume 37, issue 3, 2015, Pages 491~501
DOI : 10.4218/etrij.15.0114.0675
Spectrum sensing is an elementary function in cognitive radio designed to monitor the existence of a primary user (PU). To achieve a high rate of detection, most techniques rely on knowledge of prior spectrum patterns, with a trade-off between high computational complexity and long sensing time. On the other hand, blind techniques ignore pattern matching processes to reduce processing time, but their accuracy degrades greatly at low signal-to-noise ratios. To achieve both a high rate of detection and short sensing time, we propose fast spectrum sensing with coordinate system (FSC) - a novel technique that decomposes a spectrum with high complexity into a new coordinate system of salient features and that uses these features in its PU detection process. Not only is the space of a buffer that is used to store information about a PU reduced, but also the sensing process is fast. The performance of FSC is evaluated according to its accuracy and sensing time against six other well-known conventional techniques through a wireless microphone signal based on the IEEE 802.22 standard. FSC gives the best performance overall.
Hybrid Fuzzy Adaptive Wiener Filtering with Optimization for Intrusion Detection
Sujendran, Revathi ; Arunachalam, Malathi ;
ETRI Journal, volume 37, issue 3, 2015, Pages 502~511
DOI : 10.4218/etrij.15.0114.0275
Intrusion detection plays a key role in detecting attacks over networks, and due to the increasing usage of Internet services, several security threats arise. Though an intrusion detection system (IDS) detects attacks efficiently, it also generates a large number of false alerts, which makes it difficult for a system administrator to identify attacks. This paper proposes automatic fuzzy rule generation combined with a Wiener filter to identify attacks. Further, to optimize the results, simplified swarm optimization is used. After training a large dataset, various fuzzy rules are generated automatically for testing, and a Wiener filter is used to filter out attacks that act as noisy data, which improves the accuracy of the detection. By combining automatic fuzzy rule generation with a Wiener filter, an IDS can handle intrusion detection more efficiently. Experimental results, which are based on collected live network data, are discussed and show that the proposed method provides a competitively high detection rate and a reduced false alarm rate in comparison with other existing machine learning techniques.
Securing Mobile Ad Hoc Networks Using Enhanced Identity-Based Cryptography
Mehr, Kamal Adli ; Niya, Javad Musevi ;
ETRI Journal, volume 37, issue 3, 2015, Pages 512~522
DOI : 10.4218/etrij.15.0114.0195
Recent developments in identity-based cryptography (IBC) have provided new solutions to problems related to the security of mobile ad hoc networks (MANETs). Although many proposals to solve problems related to the security of MANETs are suggested by the research community, there is no one solution that fits all. The interdependency cycle between secure routing and security services makes the use of IBC in MANETs very challenging. In this paper, two novel methods are proposed to eliminate the need for this cycle. One of these methods utilizes a key pool to secure routes for the distribution of cryptographic materials, while the other adopts a pairing-based key agreement method. Furthermore, our proposed methods utilize threshold cryptography for shared secret and private key generation to eliminate the "single point of failure" and distribute cryptographic services among network nodes. These characteristics guarantee high levels of availability and scalability for the proposed methods. To illustrate the effectiveness and capabilities of the proposed methods, they are simulated and compared against the performance of existing methods.
HV-SoP Technology for Maskless Fine-Pitch Bumping Process
Son, Jihye ; Eom, Yong-Sung ; Choi, Kwang-Seong ; Lee, Haksun ; Bae, Hyun-Cheol ; Lee, Jin-Ho ;
ETRI Journal, volume 37, issue 3, 2015, Pages 523~532
DOI : 10.4218/etrij.15.0114.0578
Recently, we have witnessed the gradual miniaturization of electronic devices. In miniaturized devices, flip-chip bonding has become a necessity over other bonding methods. For the electrical connections in miniaturized devices, fine-pitch solder bumping has been widely studied. In this study, high-volume solder-on-pad (HV-SoP) technology was developed using a novel maskless printing method. For the new SoP process, we used a special material called a solder bump maker (SBM). Using an SBM, which consists of resin and solder powder, uniform bumps can easily be made without a mask. To optimize the height of solder bumps, various conditions such as the mask design, oxygen concentration, and processing method are controlled. In this study, a double printing method, which is a modification of a general single printing method, is suggested. The average, maximum, and minimum obtained heights of solder bumps are
, respectively. It is expected that the HV-SoP process will reduce the costs for solder bumping and will be used for electrical interconnections in fine-pitch flip-chip bonding.
Hybrid Linear Closed-Form Solution in Wireless Localization
Cho, Seong Yun ;
ETRI Journal, volume 37, issue 3, 2015, Pages 533~540
DOI : 10.4218/etrij.15.0114.0382
In wireless localization, several linear closed-form solution (LCS) methods have been investigated as a direct result of the drawbacks that plague the existing iterative methods, such as the local minimum problem and heavy computational burden. Among the known LCS methods, both the direct solution method and the difference of squared range measurements method are considered in this paper. These LCS methods do not have any of the aforementioned problems that occur in the existing iterative methods. However, each LCS method does have its own individual error property. In this paper, a hybrid LCS method is presented to reduce these errors. The hybrid LCS method integrates the two aforementioned LCS methods by using two check points that give important information on the probability of occurrence of each LCS's individual error. The results of several Monte Carlo simulations show that the proposed method has a good performance. The solutions provided by the proposed method are accurate and reliable. The solutions do not have serious errors such as those that occur in the conventional standalone LCS and iterative methods.
Classification-Based Approach for Hybridizing Statistical and Rule-Based Machine Translation
Park, Eun-Jin ; Kwon, Oh-Woog ; Kim, Kangil ; Kim, Young-Kil ;
ETRI Journal, volume 37, issue 3, 2015, Pages 541~550
DOI : 10.4218/etrij.15.0114.1017
In this paper, we propose a classification-based approach for hybridizing statistical machine translation and rulebased machine translation. Both the training dataset used in the learning of our proposed classifier and our feature extraction method affect the hybridization quality. To create one such training dataset, a previous approach used auto-evaluation metrics to determine from a set of component machine translation (MT) systems which gave the more accurate translation (by a comparative method). Once this had been determined, the most accurate translation was then labelled in such a way so as to indicate the MT system from which it came. In this previous approach, when the metric evaluation scores were low, there existed a high level of uncertainty as to which of the component MT systems was actually producing the better translation. To relax such uncertainty or error in classification, we propose an alternative approach to such labeling; that is, a cut-off method. In our experiments, using the aforementioned cut-off method in our proposed classifier, we managed to achieve a translation accuracy of 81.5% - a 5.0% improvement over existing methods.
Robust Multi-person Tracking for Real-Time Intelligent Video Surveillance
Choi, Jin-Woo ; Moon, Daesung ; Yoo, Jang-Hee ;
ETRI Journal, volume 37, issue 3, 2015, Pages 551~561
DOI : 10.4218/etrij.15.0114.0629
We propose a novel multiple-object tracking algorithm for real-time intelligent video surveillance. We adopt particle filtering as our tracking framework. Background modeling and subtraction are used to generate a region of interest. A two-step pedestrian detection is employed to reduce the computation time of the algorithm, and an iterative particle repropagation method is proposed to enhance its tracking accuracy. A matching score for greedy data association is proposed to assign the detection results of the two-step pedestrian detector to trackers. Various experimental results demonstrate that the proposed algorithm tracks multiple objects accurately and precisely in real time.
Software Pipeline-Based Partitioning Method with Trade-Off between Workload Balance and Communication Optimization
Huang, Kai ; Xiu, Siwen ; Yu, Min ; Zhang, Xiaomeng ; Yan, Rongjie ; Yan, Xiaolang ; Liu, Zhili ;
ETRI Journal, volume 37, issue 3, 2015, Pages 562~572
DOI : 10.4218/etrij.15.0114.0502
For a multiprocessor System-on-Chip (MPSoC) to achieve high performance via parallelism, we must consider how to partition a given application into different components and map the components onto multiple processors. In this paper, we propose a software pipeline-based partitioning method with cyclic dependent task management and communication optimization. During task partitioning, simultaneously considering computation load balance and communication optimization can cause interference, which leads to performance loss. To address this issue, we formulate their constraints and apply an integer linear programming approach to find an optimal partitioning result - one that requires a trade-off between these two factors. Experimental results on a reconfigurable MPSoC platform demonstrate the effectiveness of the proposed method, with 20% to 40% performance improvements compared to a traditional software pipeline-based partitioning method.
Secure Mobile Agents in eCommerce with Forward-Secure Undetachable Digital Signatures
Shi, Yang ; Zhao, Qinpei ; Liu, Qin ;
ETRI Journal, volume 37, issue 3, 2015, Pages 573~583
DOI : 10.4218/etrij.15.0114.0657
We introduce the idea of a forward-secure undetachable digital signature (FS-UDS) in this paper, which enables mobile agents to generate undetachable digital signatures with forward security of the original signer's signing key. The definition and security notion of an FS-UDS scheme are given. Then, the construction of a concrete FS-UDS scheme is proposed; and the proof of security for the proposed scheme is also provided. In the proposed scheme, mobile agents need not carry the signing key when they generate digital signatures on behalf of the original signer, so the signing key will not be compromised. At the same time, the encrypted function is combined with the original signer's requirement; therefore, misuse of the signing algorithm can be prevented. Furthermore, in the case where a hacker has accessed the signing key of the original signer, he/she is not able to forge a signature for any time period prior to when the key was obtained.
Mutual Information Analysis for Three-Phase Dynamic Current Mode Logic against Side-Channel Attack
Kim, Hyunmin ; Han, Dong-Guk ; Hong, Seokhie ;
ETRI Journal, volume 37, issue 3, 2015, Pages 584~594
DOI : 10.4218/etrij.15.0114.0297
To date, many different kinds of logic styles for hardware countermeasures have been developed; for example, SABL, TDPL, and DyCML. Current mode-based logic styles are useful as they consume less power compared to voltage mode-based logic styles such as SABL and TDPL. Although we developed TPDyCML in 2012 and presented it at the WISA 2012 conference, we have further optimized it in this paper using a binary decision diagram algorithm and confirmed its properties through a practical implementation of the AES S-box. In this paper, we will explain the outcome of HSPICE simulations, which included correlation power attacks, on AES S-boxes configured using a compact NMOS tree constructed from either SABL, CMOS, TDPL, DyCML, or TPDyCML. In addition, to compare the performance of each logic style in greater detail, we will carry out a mutual information analysis (MIA). Our results confirm that our logic style has good properties as a hardware countermeasure and 15% less information leakage than those secure logic styles used in our MIA.
Discrete Multiwavelet-Based Video Watermarking Scheme Using SURF
Narkedamilly, Leelavathy ; Evani, Venkateswara Prasad ; Samayamantula, Srinivas Kumar ;
ETRI Journal, volume 37, issue 3, 2015, Pages 595~605
DOI : 10.4218/etrij.15.0114.0012
This paper proposes a robust, imperceptible block-based digital video watermarking algorithm that makes use of the Speeded Up Robust Feature (SURF) technique. The SURF technique is used to extract the most important features of a video. A discrete multiwavelet transform (DMWT) domain in conjunction with a discrete cosine transform is used for embedding a watermark into feature blocks. The watermark used is a binary image. The proposed algorithm is further improved for robustness by an error-correction code to protect the watermark against bit errors. The same watermark is embedded temporally for every set of frames of an input video to improve the decoded watermark correlation. Extensive experimental results demonstrate that the proposed DMWT domain video watermarking using SURF features is robust against common image processing attacks, motion JPEG2000 compression, frame averaging, and frame swapping attacks. The quality of a watermarked video under the proposed algorithm is high, demonstrating the imperceptibility of an embedded watermark.
Toward Accurate Road Detection in Challenging Environments Using 3D Point Clouds
Byun, Jaemin ; Seo, Beom-Su ; Lee, Jihong ;
ETRI Journal, volume 37, issue 3, 2015, Pages 606~616
DOI : 10.4218/etrij.15.0113.1131
In this paper, we propose a novel method for road recognition using 3D point clouds based on a Markov random field (MRF) framework in unstructured and complex road environments. The proposed method is focused on finding a solution for an analysis of traversable regions in challenging environments without considering an assumption that has been applied in many past studies; that is, that the surface of a road is ideally flat. The main contributions of this research are as follows: (a) guidelines for the best selection of the gradient value, the average height, the normal vectors, and the intensity value and (b) how to mathematically transform a road recognition problem into a classification problem that is based on MRF modeling in spatial and visual contexts. In our experiments, we used numerous scans acquired by an HDL-64E sensor mounted on an experimental vehicle. The results show that the proposed method is more robust and reliable than a conventional approach based on a quantity evaluation with ground truth data for a variety of challenging environments.
Development of Steering Control System for Autonomous Vehicle Using Geometry-Based Path Tracking Algorithm
Park, Myungwook ; Lee, Sangwoo ; Han, Wooyong ;
ETRI Journal, volume 37, issue 3, 2015, Pages 617~625
DOI : 10.4218/etrij.15.0114.0123
In this paper, a steering control system for the path tracking of autonomous vehicles is described. The steering control system consists of a path tracker and primitive driver. The path tracker generates the desired steering angle by using the look-ahead distance, vehicle heading, and a lateral offset. A method for applying an autonomous vehicle to path tracking is an advanced pure pursuit method that can reduce cutting corners, which is a weakness of the pure pursuit method. The steering controller controls the steering actuator to follow the desired steering angle. A servo motor is installed to control the steering handle, and it can transmit the steering force using a belt and pulley. We designed a steering controller that is applied to a proportional integral differential controller. However, because of a dead band, the path tracking performance and stability of autonomous vehicles are reduced. To overcome the dead band, a dead band compensator was developed. As a result of the compensator, the path tracking performance and stability are improved.
Adaptive Multimodal In-Vehicle Information System for Safe Driving
Park, Hye Sun ; Kim, Kyong-Ho ;
ETRI Journal, volume 37, issue 3, 2015, Pages 626~636
DOI : 10.4218/etrij.15.0114.1104
This paper proposes an adaptive multimodal in-vehicle information system for safe driving. The proposed system filters input information based on both the priority assigned to the information and the given driving situation, to effectively manage input information and intelligently provide information to the driver. It then interacts with the driver using an adaptive multimodal interface by considering both the driving workload and the driver's cognitive reaction to the information it provides. It is shown experimentally that the proposed system can promote driver safety and enhance a driver's understanding of the information it provides by filtering the input information. In addition, the system can reduce a driver's workload by selecting an appropriate modality and corresponding level with which to communicate. An analysis of subjective questionnaires regarding the proposed system reveals that more than 85% of the respondents are satisfied with it. The proposed system is expected to provide prioritized information through an easily understood modality.
Enhanced Common-Mode Noise Rejection Method Based on Impedance Mismatching Compensation for Wireless Capsule Endoscopy Systems
Hwang, Won-Jun ; Kim, Ki-Yun ; Choi, Hyung-Jin ;
ETRI Journal, volume 37, issue 3, 2015, Pages 637~645
DOI : 10.4218/etrij.15.0114.1322
Common-mode noise (CMN) is an unresolved problem in wireless capsule endoscopy (WCE) systems. In a WCE system, CMN originates from various electric currents found within the human body or external interference sources and causes critical demodulation performance degradation. The differential operation, a typical method for the removal of CMN rejection, can remove CMN by subtracting two signals simultaneously received by two reception sensors attached to a human body. However, when there is impedance mismatching between the two reception sensors, the differential operation method cannot completely remove CMN. Therefore, to overcome this problem, we propose an enhanced CMN rejection method. The proposed method performs not only subtraction but also addition between two received signals. Then a CMN ratio can be estimated by sufficient accumulation of division operation outcomes between the subtraction and addition outputs during the guard period. Finally, we can reject the residual CMN by combining the subtraction and addition outputs.