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        • KCI등재

          Improvement in DRX Power Saving for Non-real-time Traffic in LTE

          Mohammad Tawhid Kawser,Mohammad Rakibul Islam,Khondoker Ziaul Islam,Mohammad Atiqul Islam,Mohammad Mehadi Hassan,Zobayer Ahmed,Rafid Hasan 한국전자통신연구원 2016 ETRI Journal Vol.38 No.4

          A discontinuous reception (DRX) operation is included in the Long Term Evolution (LTE) system to achieve power saving and prolonged battery life of the user equipment. An improvement in DRX power saving usually leads to a potential increase in the packet delay. An optimum DRX configuration depends on the current traffic, which is not easy to estimate accurately, particularly for non-real-time applications. In this paper, we propose a novel way to vary the DRX cycle length, avoiding a continuous estimation of the data traffic when only non-real-time applications are running with no active real-time applications. Because a small delay in non-real-time traffic does not essentially impact the user’s experience adversely, we deliberately allow a limited amount of delay in our proposal to attain a significant improvement in power saving. Our proposal also improves the delay in service resumption after a long period of inactivity. We use a stochastic analysis assuming an M/G/1 queue to validate this improvement.

        • SCISCIESCOPUSKCI등재

          Improvement in DRX Power Saving for Non-real-time Traffic in LTE

          Kawser, Mohammad Tawhid,Islam, Mohammad Rakibul,Islam, Khondoker Ziaul,Islam, Mohammad Atiqul,Hassan, Mohammad Mehadi,Ahmed, Zobayer,Hasan, Rafid Electronics and Telecommunications Research Instit 2016 ETRI Journal Vol.38 No.4

          A discontinuous reception (DRX) operation is included in the Long Term Evolution (LTE) system to achieve power saving and prolonged battery life of the user equipment. An improvement in DRX power saving usually leads to a potential increase in the packet delay. An optimum DRX configuration depends on the current traffic, which is not easy to estimate accurately, particularly for non-real-time applications. In this paper, we propose a novel way to vary the DRX cycle length, avoiding a continuous estimation of the data traffic when only non-real-time applications are running with no active real-time applications. Because a small delay in non-real-time traffic does not essentially impact the user's experience adversely, we deliberately allow a limited amount of delay in our proposal to attain a significant improvement in power saving. Our proposal also improves the delay in service resumption after a long period of inactivity. We use a stochastic analysis assuming an M/G/1 queue to validate this improvement.

        • KCI등재

          협력통신을 이용하는 무선 센서네트워크에서의 에너지 소비 감소를 위한 속도와 훈련심볼의 오버헤드 임계값 추정

          모하메드 라키불 이슬람(Mohammad Rakibul Islam),김진상(Jinsang Kim),조원경(Won-Kyung Cho) 한국통신학회 2009 韓國通信學會論文誌 Vol.35 No.6

          본 논문에서는 에너지가 제한적인 무선 센서네트워크에서 MIMO 기반 협력통신을 가능하게 하는 훈련심볼의 오버헤드와 데이터 수집노드(DGN)의 속도의 임계값을 제안한다. 두개의 송수신 안테나가 있는 경우에 대하여 에너지 효율과 지연값에 대한 성능을 분석하였다. 센서로부터 데이터 수집노드까지 장거리 통신을 할 경우에 대하여 기존의 SISO 보다 에너지를 적게 소모하는 MIMO 기반 협력통신 무선 센서 네트워크의 속도와 훈련심볼의 오버헤드 임계값들을 구하였으며 이들의 상관관계도 분석하였다. A boundary value of the velocity of data gathering node (DGN) and a critical value for training overhead beyond which the scheme will not be feasible for a Multiple Input Multiple Output (MIMO) based cooperative communication for energy-limited wireless sensor networks is proposed in this paper. The performance in terms of energy efficiency and delay for a combination of two transmitting and two receiving antennas is analyzed. The results show that a set of critical value of velocity and training overhead pair is present for the long haul communication from the sensors to the data gathering node. Finally a relation between training overhead and velocity is simulated.

        • 무선 센서 네트워크를 위한 cooperative 기법 : 경계값 추정을 위한 사례연구

          모하마드 라키불,이슬람,김진상,조원경 경희-다반 ASIC 설계교육센터 2007 경희-다반 ASIC센터 논문집 Vol.8 No.-

          A boundary value of the velocity of Data Gathehng Node (DGN) and a critical value for training overhead beyond which the scheme will not be feasible for a Multiple Input Multiple Output (MIMO) based cooperative communication for energy-limited wireless sensor networks is proposed in this paper. The performance in terms of energy efficiency and delay for a cumbinalion of two transmitting and two receiving antennas is analyzed. The results show that a set of critical value of velocity and training overhead pair is present for the long haul communication from the sensors to the data gathering node. Finally a graphical relation between training overhead and velocity is simulated.

        • 에너지 효율적인 무선 센서 네트워크를 위한 선택적 cooperative 기법

          모하마드 라키불,이슬람,김진상,조원경 경희-다반 ASIC 설계교육센터 2007 경희-다반 ASIC센터 논문집 Vol.8 No.-

          An energy efficient cooperative technique is proposed for the IEEE 1451 based Wireless Sensor Nerworks. Selected numbers of Wireless Transducer Interface Modulcs (WTIMs) are used to form a Multiple Input Single Output (MISO) structure wirelessly connected with a Network Capable Application Processor (NCAP). Energy efficiency and delay of the proposed architecture are derived for different combination of cluster size and selected number of WTIMs. Optimized constellation parameters are used for evaluating derived parameters. The results show that the selected MISO structure outperforms the unselected MISO structure and it shows energy efficient performance than SISO structure after a certain distance.

        • KCI등재

          A novel particle swarm optimization-based grey model for the prediction of warehouse performance

          Md. Rakibul Islam,Syed Mithun Ali,Amir Mohammad Fathollahi-Fard,Golam Kabir 한국CDE학회 2021 Journal of computational design and engineering Vol.8 No.2

          Warehouses constitute a key component of supply chain networks. An improvement to the operational efficiency and the productivity of warehouses is crucial for supply chain practitioners and industrial managers. Overall warehouse efficiency largely depends on synergic performance. The managers preemptively estimate the overall warehouse performance (OWP), which requires an accurate prediction of a warehouse’s key performance indicators (KPIs). This research aims to predict the KPIs of a ready-made garment (RMG) warehouse in Bangladesh with a low forecasting error in order to precisely measure OWP. Incorporating advice from experts, conducting a literature review, and accepting the limitations of data availability, this study identifies 13 KPIs. The traditional grey method (GM)—the GM (1, 1) model—is established to estimate the grey data with limited historical information but not absolute. To reduce the limitations of GM (1, 1), this paper introduces a novel particle swarm optimization (PSO)-based grey model—PSOGM (1, 1)—to predict the warehouse’s KPIs with less forecasting error. This study also uses the genetic algorithm (GA)-based grey model—GAGM (1, 1)—the discrete grey model—DGM (1, 1)—to assess the performance of the proposed model in terms of the mean absolute percentage error and other assessment metrics. The proposed model outperforms the existing grey models in projecting OWP through the forecasting of KPIs over a 5-month period. To find out the optimal parameters of the PSO and GA algorithms before combining them with the grey model, this study adopts the Taguchi design method. Finally, this study aims to help warehouse professionals make quick OWP estimations in advance to take control measures regarding warehouse productivity and efficiency.

        • KCI등재

          FER Performance Evaluation and Enhancement of IEEE 802.11 a/g/p WLAN over Multipath Fading Channels in GNU Radio and USRP N200 Environment

          ( Muhammad Morshed Alam ),( Mohammad Rakibul Islam ),( Muhammad Yeasir Arafat ),( Feroz Ahmed ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.1

          In this paper, authors have been evaluated the Frame Error Rate (FER) performance of IEEE 802.11 a/g/p standard 5 GHz frequency band WLAN over Rayleigh and Rician distributed fading channels in presence of Additive White Gaussian Noise (AWGN). Orthogonal Frequency Division Multiplexing (OFDM) based transceiver is implemented by using real-time signal processing frameworks (IEEE 802.11 Blocks) in GNU Radio Companion (GRC) and Ettus USRP N200 is used to process the symbol over the wireless radio channel. The FER is calculated for each sub-carrier conventional modulation schemes used by OFDM such as BPSK, QPSK, 16, 64-QAM with different punctuated coding rates. More precise SNR is computed by modifying the SNR calculation process of YANS and NIST error rate model to estimate more accurate FER. Here, real-time signal constellations, OFDM signal spectrums etc. are also observed to find the effect of multipath propagation of signals through flat and frequency selective fading channels. To reduce the error rate due to the multipath fading effect and Doppler shifting, channel estimation (CE) and equalization techniques such as Least Square (LS) and training based adaptive Least Mean Square (LMS) algorithm are applied in the receiver. The simulation work is practically verified at GRC by turning into a pair of Software Define Radio (SDR) as a simultaneous transceiver.

        • SCIESCOPUSKCI등재

          FER Performance Evaluation and Enhancement of IEEE 802.11 a/g/p WLAN over Multipath Fading Channels in GNU Radio and USRP N200 Environment

          Alam, Muhammad Morshed,Islam, Mohammad Rakibul,Arafat, Muhammad Yeasir,Ahmed, Feroz Korean Society for Internet Information 2018 KSII Transactions on Internet and Information Syst Vol.12 No.1

          In this paper, authors have been evaluated the Frame Error Rate (FER) performance of IEEE 802.11 a/g/p standard 5 GHz frequency band WLAN over Rayleigh and Rician distributed fading channels in presence of Additive White Gaussian Noise (AWGN). Orthogonal Frequency Division Multiplexing (OFDM) based transceiver is implemented by using real-time signal processing frameworks (IEEE 802.11 Blocks) in GNU Radio Companion (GRC) and Ettus USRP N200 is used to process the symbol over the wireless radio channel. The FER is calculated for each sub-carrier conventional modulation schemes used by OFDM such as BPSK, QPSK, 16, 64-QAM with different punctuated coding rates. More precise SNR is computed by modifying the SNR calculation process of YANS and NIST error rate model to estimate more accurate FER. Here, real-time signal constellations, OFDM signal spectrums etc. are also observed to find the effect of multipath propagation of signals through flat and frequency selective fading channels. To reduce the error rate due to the multipath fading effect and Doppler shifting, channel estimation (CE) and equalization techniques such as Least Square (LS) and training based adaptive Least Mean Square (LMS) algorithm are applied in the receiver. The simulation work is practically verified at GRC by turning into a pair of Software Define Radio (SDR) as a simultaneous transceiver.

        • The Use of Plants in Indigenous Health Care Practice of the Hajong Tribe Community in North Eastern Bangladesh

          Md. Parvez Rana,Md. Shawkat Islam Sohel,Sayma Akhter,Mohammad Rakibul Hassan 강원대학교 산림과학연구소 2009 Journal of Forest Science Vol.25 No.1

          An ethno-medical investigation was carried out to understand the use of plants in indigenous health care practice of the Hajong tribe community in North Eastern Bangladesh. The study of ethnobotany relating to any tribe is in itself a very intricate or long-winded process. The present study was done through structured questionnaires in consultations with the tribal practitioners and has resulted in the documentation of 25 plant species belonging to 21 families including herbs (36%), shrubs (32%), trees (28%) and climber (4%) were frequently used by the Hajong tribe for curing 27 ailments. For curing ailments, the use of aboveground plant parts was higher (86.67%) than the underground plant parts (13.33%). Leaf was used in the majority of cases for medicinal preparation (13 species), followed by fruits (7 species), root/rhizome (4 species), whole plant (3 species) and besides these, seed, latex and bark were used one species each, respectively. The study thus underlines the potentials of the ethnobotanical research and the need for the documentation of indigenous healthcare knowledge pertaining to the medicinal plant utilization for the greater benefit of mankind.

        • KCI등재

          The Use of Plants in Indigenous Health Care Practice of the Hajong Tribe Community in North Eastern Bangladesh

          Rana, Md. Parvez,Sohel, Md. Shawkat Islam,Akhter, Sayma,Hassan, Mohammad Rakibul Institute of Forest Science 2009 Journal of Forest Science Vol.25 No.1

          An ethno-medical investigation was carried out to understand the use of plants in indigenous health care practice of the Hajong tribe community in North Eastern Bangladesh. The study of ethnobotany relating to any tribe is in itself a very intricate or long-winded process. The present study was done through structured questionnaires in consultations with the tribal practitioners and has resulted in the documentation of 25 plant species belonging to 21 families including herbs (36%), shrubs (32%), trees (28%) and climber (4%) were frequently used by the Hajong tribe for curing 27 ailments. For curing ailments, the use of aboveground plant parts was higher (86.67%) than the underground plant parts (13.33%). Leaf was used in the majority of cases for medicinal preparation (13 species), followed by fruits (7 species), root/rhizome (4 species), whole plant (3 species) and besides these, seed, latex and bark were used one species each, respectively. The study thus underlines the potentials of the ethnobotanical research and the need for the documentation of indigenous healthcare knowledge pertaining to the medicinal plant utilization for the greater benefit of mankind.

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