Computer Science and Communication Engineering : [49]

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Collection's Items (Sorted by Submit Date in Descending order): 1 to 20 of 49
  • item.jpg
  • Article


  • Authors: Le, Thanh Xuyen; Le, Trung Thanh; Dinh, Van Viet; Tran, Quoc Long; Nguyen, Linh Trung; Nguyen, Duc Thuan (2017)

  • In the clinical diagnosis of epilepsy using electroencephalogram (EEG) data, an accurate automatic epileptic spikes detection system is highly useful and meaningful in that the conventional manual process is not only very tedious and time-consuming, but also subjective since it depends on the knowledge and experience of the doctors. In this paper, motivated by significant advantages and lots of achieved successes of deep learning in data mining, we apply Deep Belief Network (DBN), which is one of the breakthrough models laid the foundation for deep learning, to detect epileptic spikes in EEG data. It is really useful in practice because the promising quality evaluation of the spike de...

  • c33.1.9.pdf.jpg
  • Article


  • Authors: Tran, Hong Viet; Nguyen, Van Vinh; Vu, Thuong Huyen; Nguyen, Le Minh (2017)

  • Reordering is a major challenge in machine translation (MT) between two languages with significant differences in word order. In this paper, we present an approach as pre-processing step based on a dependency parser in phrase-based statistical machine translation (SMT) to learn automatic and manual reordering rules from English to Vietnamese. The dependency parse tree and transformation rules are used to reorder the source sentences and applied for systems translating English to Vietnamese. We evaluated our approach and compared on English-Vietnamese machine translation tasks, and showed that it outperforms the baseline phrase-based SMT system.

  • c33.1.8.pdf.jpg
  • Article


  • Authors: Ho, Manh Cuong; Vu, Van Yem (2017)

  • In this paper, we present a method for determining complex permittivity of materials using two different thicknesses of the sample placed in free space. The proposed method is based on the use of transmission having the same geometry with different thicknesses with the aim to determine the complex propagation constant (γ). The reflection and transmission coefficients (S11 and S21) of material samples are determined using a free-space measurement system. The system consists of transmit and receive horn antennas operating at X-band. The complex permittivity of materials is calculated from the values of γ, in turns received from S11 and S21. The proposed method is tested with different m...

  • c33.1.7.pdf.jpg
  • Article


  • Authors: Duong, Thi Thanh Tu; Nguyen, Gia Thang; Nguyen, Thi Bich Phuong; Vu, Van Yem (2017)

  • A structure, the proposed MIMO antenna is compact in size and designed on FR4 substrate with total dimension of 37 x 43.6 x 6 m3. At first, a single PIFA antenna is presented using U-shaped slots in radiating patch which puts forward the antenna resonant in three frequencies: 2.4GHz, 3.5GHz and 6.3GHz with bandwidth of 8.87%, 18.29.% and 2.53 % respectively for Wi-Fi, Wimax/LTE and Direct Broadcast Satellite DBS of C channel applications. Good reflection coefficient, antenna gain, and radiation pattern characteristics are obtained in the frequency band of interest. Secondly, the paper has put forward another single type of tri-band PIFA which uses double rectangular shape of Defected...

  • c33.1.6.pdf.jpg
  • Article


  • Authors: Duong, Duc Tran; Pham, Son Bao; Tan, Hanh (2017)

  • In this paper, we investigate the author profiling task for Vietnamese forum posts to predict demographic attributes, such as gender, age, occupation, and location of the author. Although we conducted the experiments on different types of features, including style-based and content-based features, we focus more on analysis the effects of content-based features. We used machine learning approaches to perform classification tasks on datasets we collected from popular forums in Vietnamese. The results show that these kinds of features work well on such a kind of short and free style messages as forum posts, in which, content-based features achieved much better results than style-based fe...

  • c33.1.5.pdf.jpg
  • Article


  • Authors: Tran, The Nghiep; Pham, Van Bien; Nguyen, Huu Minh (2017)

  • In this paper, a new amplify and forward (AF) asynchronous cooperative relay networks using maximum ratio combining (MRC) and transmit antenna selection (TAS) technique is considered. In order to obtain a maximal received diversity gain, the received signal vectors of all antennas of the each relay node are jointly combined by MRC technique in the first phase. Then, only one the selected antenna of each relay will amplify and retransmit the resulting MRC signal vectors to the destination node in the second transmission step of network. The proposed scheme not only offers to reduce the interference components induced by inter-symbol interference (ISI) among the relay nodes, but also ca...

  • c33.1.4.pdf.jpg
  • Article


  • Authors: Tang, The Toan; Nguyen, Minh Tran; Truong, Vu Bang Giang (2017)

  • This paper proposes a 8 x 1 sprout-shaped antenna array with low sidelobe level (SLL) for outdoor point to point applications. The array has the dimensions of 165 mm x 195 mm x 1.575 mm and is designed on Rogers RT/Duroid 5870tm with the thickness of 1.575 mm and permittivity of 2.33. In order to achieve low SLL, Chebyshev distribution weights corresponding to SLL preset at -30 dB has been applied to design the feed of the array. Unequal T-junction dividers has been used to ensure that the output powers are proportional to the Chebyshev amplitude distribution. A reflector has been added to the back of the antenna to improve the directivity. The simulated results show that the proposed...

  • c33.1.3.pdf.jpg
  • Article


  • Authors: Tang, Toan The; Nguyen, Tran Minh; Truong, Vu Bang Giang (2017)

  • This paper proposes a feeding networking to gain low sidelobe levels for microstrip linear antenna arrays. The procedure to design a feeding network using Chebyshev weighting method will be proposed and presented. As a demonstration, a feeding network for 8×1 elements linear array with Chebyshev distribution weights (preset sidelobe level of -25 dB) has been designed. An unequal T-junction power divider has been applied in designing the feeding network to guarantee the output powers the same as Chebyshev weights. The obtained results of the amplitudes at each output port have been validated with theory data. The phases of output signals are almost equal at all ports. The proposed feed...

  • c33.1.2.pdf.jpg
  • Article


  • Authors: Dang, Hung Van; Nguyen, Dong Trinh; Truong, Hoang Anh (2017)

  • Interaction Protocol specification is an important part for component interface specification. To use a component, the environment must conform to the interaction protocol specified in the interface of the component. We give a powerful technique to specify protocols which can capture the constraints on temporal order, concurrency, and timing. We also show that the problem of checking if a timed automaton conforms to a given real-time protocol is decidable and develop a decision procedure for solving the problem.

  • 151-12-623-2-10-20171011.pdf.jpg
  • Article


  • Authors: Vu, Tuan Anh; Pham, Tuan Dinh; Bach, Duong Gia Bach (2017)

  • This paper presents high-efficiency high-gain 2.4 GHz power amplifiers (PAs) for wireless communications. Two class-B PAs are designed and verified in 0.13 µm CMOS mixed-signal/RF process provided by TSMC. The PAs employs cascode topologies with wideband multi-stage matchings. The single-stage cascode PA is designed for a high power added efficiency (PAE) of 35.4% while the gain is 20.4 dB over the -3 dB bandwidth between 2.4 GHz and 2.48 GHz. The two-stage cascode PA is targeted for a high gain of 37.7 dB while it exhibits a peak PAE of 24.1%. Supplied by 1.2 V supply voltages, the PAs consume DC powers of 4.5 mW and 9 mW, respectively.

  • Swarm Optimization Approach for Real Light Source Detection of Multi-robot System.pdf.jpg
  • Article


  • Authors: Hoang, Anh Quy; Pham, Minh Trien (2016)

  • Exploration and searching in unknown or hazardous environments using multi-robot systems (MRS) is among the principal topics in robotics. There have been numerous works on searching and detection of odor, fire or pollution sources. In this paper, a modified Particle Swarm Optimization Algorithm (PSO) was presented for MRS on detecting light sources, namely APSO. In the proposed algorithm, an integration of conventional PSO and Artificial Potential Field (APF) is employed to use swarm intelligence for space exploration and light source detection. The formulas for APSO velocities are based on those of PSO and APF. Furthermore, each particle is surrounded by an APF that forms ...

  • Some Improvements of Fuzzy Clustering Algorithms Using Picture Fuzzy Sets and Applications For Geographic Data Clustering.pdf.jpg
  • Article


  • Authors: Nguyen, Dinh Hoa; Le, Hoang Son; Pham, Huy Thong (2016)

  • This paper summarizes the major findings of the research project under the code name QG.14.60. The research aims to enhancement of some fuzzy clustering methods by the mean of more generalized fuzzy sets. The main results are: (1) Improve a distributed fuzzy clustering method for big data using picture fuzzy sets; design a novel method called DPFCM to reduce communication cost using the facilitator model (instead of the peer-to-peer model) and the picture fuzzy sets. The experimental evaluations show that the clustering quality of DPFCM is better than the original algorithm while ensuring reasonable computational time. (2) Apply picture fuzzy clustering for weather nowcasting proble...

  • Multi-criteria Group Decision Making with Picture Linguistic Numbers.pdf.jpg
  • Article


  • Authors: Pham, Hong Phong; Bui, Cong Cuong (2016)

  • In 2013, Cuong and Kreinovich defined picture fuzzy set (PFS) which is a direct extension of fuzzy set (FS) and intuitionistic fuzzy set (IFS). Wang et al. (2014) proposed intuitionistic linguistic number (ILN) as a combination of IFS and linguistic approach. Motivated by PFS and linguistic approach, this paper introduces the concept of picture linguistic number (PLN), which constitutes a generalization of ILN for picture circumstances. For multi-criteria group decision making (MCGDM) problems with picture linguistic information, we define a score index and two accuracy indexes of PLNs, and propose an approach to the comparison between two PLNs. Simultaneously, some operation laws for...

  • Design of LMS Based Adaptive Beamformer for ULA Antennas.pdf.jpg
  • Article


  • Authors: Tong, Thị Luyen; Truong, Vu Bang Giang (2016)

  • This paper proposes a design of an adaptive beamformer for arbitrarily Uniformly spaced Linear Array (ULA) antennas. Least Mean Square (LMS), a prevalent adaptive beamforming algorithm, has been employed in the beamformer for the ULA antennas. A procedure has been introduced to validate the proposed design. Applying the proposal, a LMS based adaptive beamformer for 8×1 ULA antennas has been built and implemented on Xilinx FPGA. The fundamental characteristics of the implemented beamformer have been measured and verified. The experimental results show that the beamformer is capable of creating appropriate weights in order to steer the main lobe of the ULA antennas to the d...

  • An Experimental Investigation of Part-Of-Speech Taggers for Vietnamese.pdf.jpg
  • Article


  • Authors: Nguyen, Tuan Phong; Truong, Quoc Tuan; Nguyen, Xuan Nam; Le, Anh Cuong (2016)

  • Part-of-speech (POS) tagging plays an important role in Natural Language Processing (NLP). Its applications can be found in many other NLP tasks such as named entity recognition, syntactic parsing, dependency parsing and text chunking. In the investigation conducted in this paper, we utilize the techniques of two widely-used toolkits, ClearNLP and Stanford POS Tagger, and develop two new POS taggers for Vietnamese, then compare them to three well-known Vietnamese taggers, namely JVnTagger, vnTagger and RDRPOSTagger. We make a systematic comparison to find out the tagger having the best performance. We also design a new feature set to measure the performance of the statistical taggers...

  • A New Pencil-Beam Planar Dipole Array Antenna for IEEE 802.11ac Outdoor Access Point Routers.pdf.jpg
  • Article


  • Authors: Tang, The Toan; Nguyen, Manh Hung; Nguyen, Tran Minh; Vu, Bang Giang (2016)

  • In this paper, a new design of pencil-beam planar dipole array antenna (PDAA) with reflector back has been designed and fabricated for IEEE 802.11ac outdoor applications. The proposed antenna is a planar array combined with a reflector. The planar array is comprised of 4 x 4 x 3 single elements which are placed on an FR4-epoxy substrate with the size of 241 mm x 194 mm x 1.6 mm. This design has very good simulation results in terms of the radiation pattern, gain and input impedance bandwidth. A very high gain of 18.2 dBi has been achieved at 5.5 GHz, and the bandwidth is relatively wide with about 23% of the center frequency, which covers the whole bandwidth allocated for the applica...

  • A Method for Automated Test Cases Generation.pdf.jpg
  • Article


  • Authors: Vu, Thi Dao; Pham, Ngoc Hung; Nguyen, Viet Ha (2016)

  • This paper proposes an automated test cases generation method from sequence diagrams, class diagrams, and object constraint language in order to solve several steps of the model-based testing process. The method supports UML 2.0 sequence diagrams including eight kinds of combined fragments. Test cases are generated with respect to the given concurrency coverage criteria. With strong concurrency coverage, generating exhaustive test cases for all concurrent interleaving sequences is exponential in size. The key idea of this method is to create selections of possible test scenarios in special case of exploring the message sequences with their possible interleaving in parallel fragments o...

  • Target tracking solution for multi-sensor data fusion in wireless sensor networks.pdf.jpg
  • Article


  • Authors: Duong, Viet Huy; Nguyen, Dinh Viet (2016)

  • Wireless sensor networks are often composed of many sensor nodes, they are powered by batteries with limited capacity. The sensor nodes are randomly scattered within in the ranger monitoring and send – receiver data using radio waves. Many research projects had demonstrated the consumption of battery power by the data transceiver occupy large compared to the calculation on the sensor node. In this paper, we propose energy saving solutions of nodes in a cluster by only choosing some nodes in the cluster to track the target and transmit this data to cluster head nodes. We based on the location of the sensor nodes in the cluster compare with the location of target and cluster head nodes ...

  • An Efficient Log Management Framework.pdf.jpg
  • Article


  • Authors: Nguyen, Van Nam; Tran, Van Cuong (2016)

  • Server monitoring is really necessary because this can help administrators to track users’ activities in order to improve user management ability, load balancing as well as to detect DDoS attacks. Usually, server monitoring is based on logging. However, logging system is always considered to be expensive in term of storage, data collection, data searching and analysis. In this paper, we introduce eLMS, an efficient and scalable log management system. In our system, the log files can be collected from multiple servers, stored in a scalable manner, appropriately indexed and fast analysed. eLMS acts both in online and off-line modes and provides a practical web-based monitoring in...

  • Selection of Appropriate Number of CRs in Cooperative Spectrum Sensing over Suzuki Fading.pdf.jpg
  • Article


  • Authors: Dinh, Thị Thai Mai; Nguyen, Thanh Long; Nguyen, Quoc Tuan (2016)

  • With the rapid development of wireless communications, the radio spectrum is becoming scarce. However, researchers have shown that many portions of licensed spectrum unused for significant periods of time. Recently, cognitive radio has been proposed as a very effective mechanism which allows Cognitive Radio Users (CRs) to utilize the idle unused licensed bands. The main challenge for a CR is to detect the existence of Primary User (PU) in order to minimize the interference to it. In this paper, we study the cooperative spectrum sensing under Suzuki composite fading channel which is the mixture of Rayleigh fading channel and Log-normal shadowing channel. Besides, we also concentrate o...

Collection's Items (Sorted by Submit Date in Descending order): 1 to 20 of 49

Computer Science and Communication Engineering : [49]

Follow this collection to receive daily e-mail notification of new additions
Collection's Items (Sorted by Submit Date in Descending order): 1 to 20 of 49
  • item.jpg
  • Article


  • Authors: Le, Thanh Xuyen; Le, Trung Thanh; Dinh, Van Viet; Tran, Quoc Long; Nguyen, Linh Trung; Nguyen, Duc Thuan (2017)

  • In the clinical diagnosis of epilepsy using electroencephalogram (EEG) data, an accurate automatic epileptic spikes detection system is highly useful and meaningful in that the conventional manual process is not only very tedious and time-consuming, but also subjective since it depends on the knowledge and experience of the doctors. In this paper, motivated by significant advantages and lots of achieved successes of deep learning in data mining, we apply Deep Belief Network (DBN), which is one of the breakthrough models laid the foundation for deep learning, to detect epileptic spikes in EEG data. It is really useful in practice because the promising quality evaluation of the spike de...

  • c33.1.9.pdf.jpg
  • Article


  • Authors: Tran, Hong Viet; Nguyen, Van Vinh; Vu, Thuong Huyen; Nguyen, Le Minh (2017)

  • Reordering is a major challenge in machine translation (MT) between two languages with significant differences in word order. In this paper, we present an approach as pre-processing step based on a dependency parser in phrase-based statistical machine translation (SMT) to learn automatic and manual reordering rules from English to Vietnamese. The dependency parse tree and transformation rules are used to reorder the source sentences and applied for systems translating English to Vietnamese. We evaluated our approach and compared on English-Vietnamese machine translation tasks, and showed that it outperforms the baseline phrase-based SMT system.

  • c33.1.8.pdf.jpg
  • Article


  • Authors: Ho, Manh Cuong; Vu, Van Yem (2017)

  • In this paper, we present a method for determining complex permittivity of materials using two different thicknesses of the sample placed in free space. The proposed method is based on the use of transmission having the same geometry with different thicknesses with the aim to determine the complex propagation constant (γ). The reflection and transmission coefficients (S11 and S21) of material samples are determined using a free-space measurement system. The system consists of transmit and receive horn antennas operating at X-band. The complex permittivity of materials is calculated from the values of γ, in turns received from S11 and S21. The proposed method is tested with different m...

  • c33.1.7.pdf.jpg
  • Article


  • Authors: Duong, Thi Thanh Tu; Nguyen, Gia Thang; Nguyen, Thi Bich Phuong; Vu, Van Yem (2017)

  • A structure, the proposed MIMO antenna is compact in size and designed on FR4 substrate with total dimension of 37 x 43.6 x 6 m3. At first, a single PIFA antenna is presented using U-shaped slots in radiating patch which puts forward the antenna resonant in three frequencies: 2.4GHz, 3.5GHz and 6.3GHz with bandwidth of 8.87%, 18.29.% and 2.53 % respectively for Wi-Fi, Wimax/LTE and Direct Broadcast Satellite DBS of C channel applications. Good reflection coefficient, antenna gain, and radiation pattern characteristics are obtained in the frequency band of interest. Secondly, the paper has put forward another single type of tri-band PIFA which uses double rectangular shape of Defected...

  • c33.1.6.pdf.jpg
  • Article


  • Authors: Duong, Duc Tran; Pham, Son Bao; Tan, Hanh (2017)

  • In this paper, we investigate the author profiling task for Vietnamese forum posts to predict demographic attributes, such as gender, age, occupation, and location of the author. Although we conducted the experiments on different types of features, including style-based and content-based features, we focus more on analysis the effects of content-based features. We used machine learning approaches to perform classification tasks on datasets we collected from popular forums in Vietnamese. The results show that these kinds of features work well on such a kind of short and free style messages as forum posts, in which, content-based features achieved much better results than style-based fe...

  • c33.1.5.pdf.jpg
  • Article


  • Authors: Tran, The Nghiep; Pham, Van Bien; Nguyen, Huu Minh (2017)

  • In this paper, a new amplify and forward (AF) asynchronous cooperative relay networks using maximum ratio combining (MRC) and transmit antenna selection (TAS) technique is considered. In order to obtain a maximal received diversity gain, the received signal vectors of all antennas of the each relay node are jointly combined by MRC technique in the first phase. Then, only one the selected antenna of each relay will amplify and retransmit the resulting MRC signal vectors to the destination node in the second transmission step of network. The proposed scheme not only offers to reduce the interference components induced by inter-symbol interference (ISI) among the relay nodes, but also ca...

  • c33.1.4.pdf.jpg
  • Article


  • Authors: Tang, The Toan; Nguyen, Minh Tran; Truong, Vu Bang Giang (2017)

  • This paper proposes a 8 x 1 sprout-shaped antenna array with low sidelobe level (SLL) for outdoor point to point applications. The array has the dimensions of 165 mm x 195 mm x 1.575 mm and is designed on Rogers RT/Duroid 5870tm with the thickness of 1.575 mm and permittivity of 2.33. In order to achieve low SLL, Chebyshev distribution weights corresponding to SLL preset at -30 dB has been applied to design the feed of the array. Unequal T-junction dividers has been used to ensure that the output powers are proportional to the Chebyshev amplitude distribution. A reflector has been added to the back of the antenna to improve the directivity. The simulated results show that the proposed...

  • c33.1.3.pdf.jpg
  • Article


  • Authors: Tang, Toan The; Nguyen, Tran Minh; Truong, Vu Bang Giang (2017)

  • This paper proposes a feeding networking to gain low sidelobe levels for microstrip linear antenna arrays. The procedure to design a feeding network using Chebyshev weighting method will be proposed and presented. As a demonstration, a feeding network for 8×1 elements linear array with Chebyshev distribution weights (preset sidelobe level of -25 dB) has been designed. An unequal T-junction power divider has been applied in designing the feeding network to guarantee the output powers the same as Chebyshev weights. The obtained results of the amplitudes at each output port have been validated with theory data. The phases of output signals are almost equal at all ports. The proposed feed...

  • c33.1.2.pdf.jpg
  • Article


  • Authors: Dang, Hung Van; Nguyen, Dong Trinh; Truong, Hoang Anh (2017)

  • Interaction Protocol specification is an important part for component interface specification. To use a component, the environment must conform to the interaction protocol specified in the interface of the component. We give a powerful technique to specify protocols which can capture the constraints on temporal order, concurrency, and timing. We also show that the problem of checking if a timed automaton conforms to a given real-time protocol is decidable and develop a decision procedure for solving the problem.

  • 151-12-623-2-10-20171011.pdf.jpg
  • Article


  • Authors: Vu, Tuan Anh; Pham, Tuan Dinh; Bach, Duong Gia Bach (2017)

  • This paper presents high-efficiency high-gain 2.4 GHz power amplifiers (PAs) for wireless communications. Two class-B PAs are designed and verified in 0.13 µm CMOS mixed-signal/RF process provided by TSMC. The PAs employs cascode topologies with wideband multi-stage matchings. The single-stage cascode PA is designed for a high power added efficiency (PAE) of 35.4% while the gain is 20.4 dB over the -3 dB bandwidth between 2.4 GHz and 2.48 GHz. The two-stage cascode PA is targeted for a high gain of 37.7 dB while it exhibits a peak PAE of 24.1%. Supplied by 1.2 V supply voltages, the PAs consume DC powers of 4.5 mW and 9 mW, respectively.

  • Swarm Optimization Approach for Real Light Source Detection of Multi-robot System.pdf.jpg
  • Article


  • Authors: Hoang, Anh Quy; Pham, Minh Trien (2016)

  • Exploration and searching in unknown or hazardous environments using multi-robot systems (MRS) is among the principal topics in robotics. There have been numerous works on searching and detection of odor, fire or pollution sources. In this paper, a modified Particle Swarm Optimization Algorithm (PSO) was presented for MRS on detecting light sources, namely APSO. In the proposed algorithm, an integration of conventional PSO and Artificial Potential Field (APF) is employed to use swarm intelligence for space exploration and light source detection. The formulas for APSO velocities are based on those of PSO and APF. Furthermore, each particle is surrounded by an APF that forms ...

  • Some Improvements of Fuzzy Clustering Algorithms Using Picture Fuzzy Sets and Applications For Geographic Data Clustering.pdf.jpg
  • Article


  • Authors: Nguyen, Dinh Hoa; Le, Hoang Son; Pham, Huy Thong (2016)

  • This paper summarizes the major findings of the research project under the code name QG.14.60. The research aims to enhancement of some fuzzy clustering methods by the mean of more generalized fuzzy sets. The main results are: (1) Improve a distributed fuzzy clustering method for big data using picture fuzzy sets; design a novel method called DPFCM to reduce communication cost using the facilitator model (instead of the peer-to-peer model) and the picture fuzzy sets. The experimental evaluations show that the clustering quality of DPFCM is better than the original algorithm while ensuring reasonable computational time. (2) Apply picture fuzzy clustering for weather nowcasting proble...

  • Multi-criteria Group Decision Making with Picture Linguistic Numbers.pdf.jpg
  • Article


  • Authors: Pham, Hong Phong; Bui, Cong Cuong (2016)

  • In 2013, Cuong and Kreinovich defined picture fuzzy set (PFS) which is a direct extension of fuzzy set (FS) and intuitionistic fuzzy set (IFS). Wang et al. (2014) proposed intuitionistic linguistic number (ILN) as a combination of IFS and linguistic approach. Motivated by PFS and linguistic approach, this paper introduces the concept of picture linguistic number (PLN), which constitutes a generalization of ILN for picture circumstances. For multi-criteria group decision making (MCGDM) problems with picture linguistic information, we define a score index and two accuracy indexes of PLNs, and propose an approach to the comparison between two PLNs. Simultaneously, some operation laws for...

  • Design of LMS Based Adaptive Beamformer for ULA Antennas.pdf.jpg
  • Article


  • Authors: Tong, Thị Luyen; Truong, Vu Bang Giang (2016)

  • This paper proposes a design of an adaptive beamformer for arbitrarily Uniformly spaced Linear Array (ULA) antennas. Least Mean Square (LMS), a prevalent adaptive beamforming algorithm, has been employed in the beamformer for the ULA antennas. A procedure has been introduced to validate the proposed design. Applying the proposal, a LMS based adaptive beamformer for 8×1 ULA antennas has been built and implemented on Xilinx FPGA. The fundamental characteristics of the implemented beamformer have been measured and verified. The experimental results show that the beamformer is capable of creating appropriate weights in order to steer the main lobe of the ULA antennas to the d...

  • An Experimental Investigation of Part-Of-Speech Taggers for Vietnamese.pdf.jpg
  • Article


  • Authors: Nguyen, Tuan Phong; Truong, Quoc Tuan; Nguyen, Xuan Nam; Le, Anh Cuong (2016)

  • Part-of-speech (POS) tagging plays an important role in Natural Language Processing (NLP). Its applications can be found in many other NLP tasks such as named entity recognition, syntactic parsing, dependency parsing and text chunking. In the investigation conducted in this paper, we utilize the techniques of two widely-used toolkits, ClearNLP and Stanford POS Tagger, and develop two new POS taggers for Vietnamese, then compare them to three well-known Vietnamese taggers, namely JVnTagger, vnTagger and RDRPOSTagger. We make a systematic comparison to find out the tagger having the best performance. We also design a new feature set to measure the performance of the statistical taggers...

  • A New Pencil-Beam Planar Dipole Array Antenna for IEEE 802.11ac Outdoor Access Point Routers.pdf.jpg
  • Article


  • Authors: Tang, The Toan; Nguyen, Manh Hung; Nguyen, Tran Minh; Vu, Bang Giang (2016)

  • In this paper, a new design of pencil-beam planar dipole array antenna (PDAA) with reflector back has been designed and fabricated for IEEE 802.11ac outdoor applications. The proposed antenna is a planar array combined with a reflector. The planar array is comprised of 4 x 4 x 3 single elements which are placed on an FR4-epoxy substrate with the size of 241 mm x 194 mm x 1.6 mm. This design has very good simulation results in terms of the radiation pattern, gain and input impedance bandwidth. A very high gain of 18.2 dBi has been achieved at 5.5 GHz, and the bandwidth is relatively wide with about 23% of the center frequency, which covers the whole bandwidth allocated for the applica...

  • A Method for Automated Test Cases Generation.pdf.jpg
  • Article


  • Authors: Vu, Thi Dao; Pham, Ngoc Hung; Nguyen, Viet Ha (2016)

  • This paper proposes an automated test cases generation method from sequence diagrams, class diagrams, and object constraint language in order to solve several steps of the model-based testing process. The method supports UML 2.0 sequence diagrams including eight kinds of combined fragments. Test cases are generated with respect to the given concurrency coverage criteria. With strong concurrency coverage, generating exhaustive test cases for all concurrent interleaving sequences is exponential in size. The key idea of this method is to create selections of possible test scenarios in special case of exploring the message sequences with their possible interleaving in parallel fragments o...

  • Target tracking solution for multi-sensor data fusion in wireless sensor networks.pdf.jpg
  • Article


  • Authors: Duong, Viet Huy; Nguyen, Dinh Viet (2016)

  • Wireless sensor networks are often composed of many sensor nodes, they are powered by batteries with limited capacity. The sensor nodes are randomly scattered within in the ranger monitoring and send – receiver data using radio waves. Many research projects had demonstrated the consumption of battery power by the data transceiver occupy large compared to the calculation on the sensor node. In this paper, we propose energy saving solutions of nodes in a cluster by only choosing some nodes in the cluster to track the target and transmit this data to cluster head nodes. We based on the location of the sensor nodes in the cluster compare with the location of target and cluster head nodes ...

  • An Efficient Log Management Framework.pdf.jpg
  • Article


  • Authors: Nguyen, Van Nam; Tran, Van Cuong (2016)

  • Server monitoring is really necessary because this can help administrators to track users’ activities in order to improve user management ability, load balancing as well as to detect DDoS attacks. Usually, server monitoring is based on logging. However, logging system is always considered to be expensive in term of storage, data collection, data searching and analysis. In this paper, we introduce eLMS, an efficient and scalable log management system. In our system, the log files can be collected from multiple servers, stored in a scalable manner, appropriately indexed and fast analysed. eLMS acts both in online and off-line modes and provides a practical web-based monitoring in...

  • Selection of Appropriate Number of CRs in Cooperative Spectrum Sensing over Suzuki Fading.pdf.jpg
  • Article


  • Authors: Dinh, Thị Thai Mai; Nguyen, Thanh Long; Nguyen, Quoc Tuan (2016)

  • With the rapid development of wireless communications, the radio spectrum is becoming scarce. However, researchers have shown that many portions of licensed spectrum unused for significant periods of time. Recently, cognitive radio has been proposed as a very effective mechanism which allows Cognitive Radio Users (CRs) to utilize the idle unused licensed bands. The main challenge for a CR is to detect the existence of Primary User (PU) in order to minimize the interference to it. In this paper, we study the cooperative spectrum sensing under Suzuki composite fading channel which is the mixture of Rayleigh fading channel and Log-normal shadowing channel. Besides, we also concentrate o...

Collection's Items (Sorted by Submit Date in Descending order): 1 to 20 of 49