Computer Science and Communication Engineering : [60]

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Collection's Items (Sorted by Submit Date in Descending order): 1 to 20 of 60
  • item.jpg
  • Article


  • Authors: Nguyen, Van Hao; Nguyen, Duc Minh; Pham, Nguyen Thanh Loan (2018)

  • In this paper, an adaptive and wide-range output DC-DC converter designed for lithium-ion (Li-Ion) battery charger circuit is proposed. The converter operates in continuous conduction mode (CCM) to provide an output voltage in response to battery voltage and a wide-range output current to ensure that circuit requirements are met. This circuit is designed on Cadence using 0.35-micromet BCD technology. Simulation results show that the circuit fully operates in CCM mode with a load current from 50 mA to 1000 mA and output voltage ripple factor is less than 1 %. Furthermore, the current supplied to the load circuit responses to three types of Li-Ion rechargeable currents. The output vo...

  • item.jpg
  • Article


  • Authors: Dao, Van Lan; Nguyen, Anh Thai; Hoang, Van Phuc (2018)

  • This paper presents a low area, low power AES-CCM authenticated encryption IP core with silicon demonstration in 180nm standard CMOS process. The proposed AES-CCM core combines a low area 8-bit single S-box AES encryption core, improved iterative structure and other optimized circuits. The implementation results show that the proposed AES-CCM core achieves very high resource efficiency with 6.5 kgates GE and the low power consumption of 11.6 µW/MHz while meeting the requirement of the operation speed for many applications including IEEE 802.15.6 WBANs. The detail implementation and optimization results are also presented and discussed

  • item.jpg
  • Article


  • Authors: Do, Dac Thiem; Ho, Van Khuong (2018)

  • Spectrum sharing environment creates cross-interference between licensed network and unlicensed network. Most existing works consider unlicensed interference (i.e., interference from unlicensed network to licensed network) while ignoring licensed interference (i.e., interference from licensed network to unlicensed network). Moreover, existing channel estimation algorithms cannot exactly estimate channel information. In this paper, impacts of licensed interference and inaccurate channel information on information security in the spectrum sharing environment is analyzed under peak transmit power bound, peak interference power bound, and Rayleigh fading. Toward this end, a secrecy outage...

  • item.jpg
  • Article


  • Authors: Le, Dao Thi Hue; Luong, Pham Van; Duong, Dinh Trieu; Xiem, HoangVan (2018)

  • Video surveillance has been playing an important role in public safety and privacy protection in recent years thanks to its capability of providing the activity monitoring an d content analyzing. However, the data associated with long hours surveillance video is huge, making it less attractive to practical applications. In this paper, we propose a low complexity, yet efficient scalable video coding solution for video surveillance system. The proposed surveillance video compression scheme is able to provide the quality scalability feature by following a layered coding structure that consists of one or several enhancement layers on the top of a base layer. In addition, to maintain the b...

  • item.jpg
  • Article


  • Authors: Tran, Ngoc Ha; Le, Nhu Hien; Hoang, Xuan Huan (2018)

  • One of the main tasks of structural biology is comparing the structure of proteins. Comparisons of protein structure can determine their functional similarities. Multigraph alignment is a useful tool for identifying functional similarities based on structural analysis. This article proposes a new algorithm for aligning protein binding sites called ACOTS-MGA. This algorithm is based on the memetic scheme. It uses the ant colony optimization (ACO) method to construct a set of solutions, then selects the best solution for implementing Tabu Search to improve the solution quality. Experimental results have shown that ACOTS-MGA outperforms state-of-the-art algorithms while producing al...

  • item.jpg
  • Article


  • Authors: Vu, Ngoc Cham; Nguyen, Tuan Anh (2018)

  • A federation is usually an alliance of organisations where users from one organisation are trusted to access resources in another organisation. The membership of federations is diverse and continually changing. Federations require distributed and dynamic security policy management to meet these challenges. We propose an authorisation policy management model, FABACD, which simplifies the management of collaborations between organisations. It allows distributed and trusted administrators to adjust the authorisation policies in a resource holding organisation, whilst ensuring that the latter remains in ultimate control. The net result is that a resource’s authorisation system is able t...

  • item.jpg
  • Article


  • Authors: Vo, Thi Ngoc Chau; Nguyen, Hua Phung (2018)

  • Educational data clustering on the students’ data collected with a program can find several groups of the students sharing the similar characteristics in their behaviors and study performance. For some programs, it is not trivial for us to prepare enough data for the clustering task. Data shortage might then influence the effectiveness of the clustering process and thus, true clusters can not be discovered appropriately. On the other hand, there are other programs that have been well examined with much larger data sets available for the task. Therefore, it is wondered if we can exploit the larger data sets from other source programs to enhance the educational data clustering task on t...

  • item.jpg
  • Article


  • Authors: Vu, Thi Ngoc Anh; Dinh, Phuc Thai; Nguyen, Hoang Duc; Dang, Thanh Hai; Do, Duc Dong (2018)

  • Reconstruction of a set of genetic sequences (founders) that can combine together to form given genetic sequences (e.g. DNA) of individuals of a population is an important problem in evolutionary biology. Such reconstruction can be modeled as a combinatorial optimization problem, in which we have to find a set of founders upon that genetic sequences of the population can be generated using a smallest number of recombinations. In this paper we propose an ant colony optimization algorithm (ACO) based method, equipped with some important improvements, for the founder DNA sequence reconstruction problem. The proposed method yields excellent performance when validating on 108 test sets fro...

  • item.jpg
  • Article


  • Authors: Le, Hong Phuong; Pham, Thai Hoang; Pham, Xuan Khoai; Nguyen, Thi Minh Huyen; Nguyen, Thi Luong; Nguyen, Minh Hiep (2018)

  • In this paper, we study semantic role labelling (SRL), a subtask of semantic parsing of natural language sentences and its application for the Vietnamese language. We present our effort in building Vietnamese PropBank, the first Vietnamese SRL corpus and a software system for labelling semantic roles of Vietnamese texts. In particular, we present a novel constituent extraction algorithm in the argument candidate identification step which is more suitable and more accurate than the common node-mapping method. In the machine learning part, our system integrates distributed word features produced by two recent unsupervised learning models in two learned statistical classifiers and makes...

  • item.jpg
  • Article


  • Authors: Dinh, Ngoc Thi (2018)

  • Search-based test data generation is a very popular domain in the field of automatic test data generation. However, existing search-based test data generators suffer fromsome problems. By combining static program analysis and search-based testing, our proposed approach overcomesone of these problems. Considering the automatic ability and the path coverage as the test adequacycriterion, this paper proposes using Particle Swarm Optimization, an alternative search technique, for automating the generation of test data for evolutionary structural testing. Experimental results demonstrate that our test data generator can generate suitable test data with higher path coverage than the previou...

  • item.jpg
  • Article


  • Authors: Tran, Hong Viet; Nguyen, Van Vinh; Vu, Thuong Huyen; Nguyen, Le Minh (2018)

  • 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 trees and transformation rules are used to reorder the source sentences and applied for systems translating from English to Vietnamese. We evaluated our approach on English-Vietnamese machine translation tasks, and showed that it outperforms the baseline phrase-based SMT system.

  • 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.

Collection's Items (Sorted by Submit Date in Descending order): 1 to 20 of 60

Computer Science and Communication Engineering : [60]

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 60
  • item.jpg
  • Article


  • Authors: Nguyen, Van Hao; Nguyen, Duc Minh; Pham, Nguyen Thanh Loan (2018)

  • In this paper, an adaptive and wide-range output DC-DC converter designed for lithium-ion (Li-Ion) battery charger circuit is proposed. The converter operates in continuous conduction mode (CCM) to provide an output voltage in response to battery voltage and a wide-range output current to ensure that circuit requirements are met. This circuit is designed on Cadence using 0.35-micromet BCD technology. Simulation results show that the circuit fully operates in CCM mode with a load current from 50 mA to 1000 mA and output voltage ripple factor is less than 1 %. Furthermore, the current supplied to the load circuit responses to three types of Li-Ion rechargeable currents. The output vo...

  • item.jpg
  • Article


  • Authors: Dao, Van Lan; Nguyen, Anh Thai; Hoang, Van Phuc (2018)

  • This paper presents a low area, low power AES-CCM authenticated encryption IP core with silicon demonstration in 180nm standard CMOS process. The proposed AES-CCM core combines a low area 8-bit single S-box AES encryption core, improved iterative structure and other optimized circuits. The implementation results show that the proposed AES-CCM core achieves very high resource efficiency with 6.5 kgates GE and the low power consumption of 11.6 µW/MHz while meeting the requirement of the operation speed for many applications including IEEE 802.15.6 WBANs. The detail implementation and optimization results are also presented and discussed

  • item.jpg
  • Article


  • Authors: Do, Dac Thiem; Ho, Van Khuong (2018)

  • Spectrum sharing environment creates cross-interference between licensed network and unlicensed network. Most existing works consider unlicensed interference (i.e., interference from unlicensed network to licensed network) while ignoring licensed interference (i.e., interference from licensed network to unlicensed network). Moreover, existing channel estimation algorithms cannot exactly estimate channel information. In this paper, impacts of licensed interference and inaccurate channel information on information security in the spectrum sharing environment is analyzed under peak transmit power bound, peak interference power bound, and Rayleigh fading. Toward this end, a secrecy outage...

  • item.jpg
  • Article


  • Authors: Le, Dao Thi Hue; Luong, Pham Van; Duong, Dinh Trieu; Xiem, HoangVan (2018)

  • Video surveillance has been playing an important role in public safety and privacy protection in recent years thanks to its capability of providing the activity monitoring an d content analyzing. However, the data associated with long hours surveillance video is huge, making it less attractive to practical applications. In this paper, we propose a low complexity, yet efficient scalable video coding solution for video surveillance system. The proposed surveillance video compression scheme is able to provide the quality scalability feature by following a layered coding structure that consists of one or several enhancement layers on the top of a base layer. In addition, to maintain the b...

  • item.jpg
  • Article


  • Authors: Tran, Ngoc Ha; Le, Nhu Hien; Hoang, Xuan Huan (2018)

  • One of the main tasks of structural biology is comparing the structure of proteins. Comparisons of protein structure can determine their functional similarities. Multigraph alignment is a useful tool for identifying functional similarities based on structural analysis. This article proposes a new algorithm for aligning protein binding sites called ACOTS-MGA. This algorithm is based on the memetic scheme. It uses the ant colony optimization (ACO) method to construct a set of solutions, then selects the best solution for implementing Tabu Search to improve the solution quality. Experimental results have shown that ACOTS-MGA outperforms state-of-the-art algorithms while producing al...

  • item.jpg
  • Article


  • Authors: Vu, Ngoc Cham; Nguyen, Tuan Anh (2018)

  • A federation is usually an alliance of organisations where users from one organisation are trusted to access resources in another organisation. The membership of federations is diverse and continually changing. Federations require distributed and dynamic security policy management to meet these challenges. We propose an authorisation policy management model, FABACD, which simplifies the management of collaborations between organisations. It allows distributed and trusted administrators to adjust the authorisation policies in a resource holding organisation, whilst ensuring that the latter remains in ultimate control. The net result is that a resource’s authorisation system is able t...

  • item.jpg
  • Article


  • Authors: Vo, Thi Ngoc Chau; Nguyen, Hua Phung (2018)

  • Educational data clustering on the students’ data collected with a program can find several groups of the students sharing the similar characteristics in their behaviors and study performance. For some programs, it is not trivial for us to prepare enough data for the clustering task. Data shortage might then influence the effectiveness of the clustering process and thus, true clusters can not be discovered appropriately. On the other hand, there are other programs that have been well examined with much larger data sets available for the task. Therefore, it is wondered if we can exploit the larger data sets from other source programs to enhance the educational data clustering task on t...

  • item.jpg
  • Article


  • Authors: Vu, Thi Ngoc Anh; Dinh, Phuc Thai; Nguyen, Hoang Duc; Dang, Thanh Hai; Do, Duc Dong (2018)

  • Reconstruction of a set of genetic sequences (founders) that can combine together to form given genetic sequences (e.g. DNA) of individuals of a population is an important problem in evolutionary biology. Such reconstruction can be modeled as a combinatorial optimization problem, in which we have to find a set of founders upon that genetic sequences of the population can be generated using a smallest number of recombinations. In this paper we propose an ant colony optimization algorithm (ACO) based method, equipped with some important improvements, for the founder DNA sequence reconstruction problem. The proposed method yields excellent performance when validating on 108 test sets fro...

  • item.jpg
  • Article


  • Authors: Le, Hong Phuong; Pham, Thai Hoang; Pham, Xuan Khoai; Nguyen, Thi Minh Huyen; Nguyen, Thi Luong; Nguyen, Minh Hiep (2018)

  • In this paper, we study semantic role labelling (SRL), a subtask of semantic parsing of natural language sentences and its application for the Vietnamese language. We present our effort in building Vietnamese PropBank, the first Vietnamese SRL corpus and a software system for labelling semantic roles of Vietnamese texts. In particular, we present a novel constituent extraction algorithm in the argument candidate identification step which is more suitable and more accurate than the common node-mapping method. In the machine learning part, our system integrates distributed word features produced by two recent unsupervised learning models in two learned statistical classifiers and makes...

  • item.jpg
  • Article


  • Authors: Dinh, Ngoc Thi (2018)

  • Search-based test data generation is a very popular domain in the field of automatic test data generation. However, existing search-based test data generators suffer fromsome problems. By combining static program analysis and search-based testing, our proposed approach overcomesone of these problems. Considering the automatic ability and the path coverage as the test adequacycriterion, this paper proposes using Particle Swarm Optimization, an alternative search technique, for automating the generation of test data for evolutionary structural testing. Experimental results demonstrate that our test data generator can generate suitable test data with higher path coverage than the previou...

  • item.jpg
  • Article


  • Authors: Tran, Hong Viet; Nguyen, Van Vinh; Vu, Thuong Huyen; Nguyen, Le Minh (2018)

  • 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 trees and transformation rules are used to reorder the source sentences and applied for systems translating from English to Vietnamese. We evaluated our approach on English-Vietnamese machine translation tasks, and showed that it outperforms the baseline phrase-based SMT system.

  • 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.

Collection's Items (Sorted by Submit Date in Descending order): 1 to 20 of 60