ABSTRACT In this paper, uncertainty in the spectrum sensing arising from channel destructive effe... more ABSTRACT In this paper, uncertainty in the spectrum sensing arising from channel destructive effects such as shadowing and fading, is controlled by proposing a non-uniform reliability based cooperative spectrum sensing (CSS) technique. Channel conditions are quantified into non-uniform reliabilities which are assigned to users based on their congruence with the global observation. An identification tag (IT), assigned on the bases of correlation between secondary user’s local observation and the primary signal status, is used to detect malicious users (MU). In the proposed scheme, unreliable as well as malicious users (always busy, always free, and always opposite) are discarded from the network leading to improved inference accuracy. Simulation results show the advantage of our proposed scheme over the conventional CSS.
ABSTRACT In this paper, uncertainty in the spectrum sensing arising from channel destructive effe... more ABSTRACT In this paper, uncertainty in the spectrum sensing arising from channel destructive effects such as shadowing and fading, is controlled by proposing a non-uniform reliability based cooperative spectrum sensing (CSS) technique. Channel conditions are quantified into non-uniform reliabilities, which are assigned to users as their identification tags (IT), and are used by the fusion center to exclude the unreliable users from the global decision. IT is used to detect malicious users (MU). Two strategies have been proposed in this work to discard the unreliable as well as malicious users (of type always opposite and always busy) from the network which leads to improved inference accuracy. The simulation results show the effectiveness of our proposed strategies where our proposed strategies demonstrates better detection performance and consider fewer users than the conventional CSS and Chair-Varshney optimum rule, in the presence of malicious users.
In this paper, we consider a hybrid underlay-overlay cognitive radio with energy harvesting. In t... more In this paper, we consider a hybrid underlay-overlay cognitive radio with energy harvesting. In the considered system, secondary user can harvest energy from the primary user's signal as well as from the other ambient sources, such as solar, wind, vibration and so on. Energy is harvested from the primary user's signal when the primary channel is found in busy state. The secondary user either operates in one of the two transmission modes; overlay and underlay in order to maximize the throughput, remains in the sleep mode in order to conserve energy, or harvests energy from the primary channel in order to maximize the remaining energy. To maximize long-term throughput of the system, we propose an access strategy in which the partially observable Markov decision process framework is used to determine action of the secondary user, and energy threshold is used to determine the transmission mode (overlay or underlay) of secondary user. Simulations show that for certain values of the system parameters, the considered system provides 60% improved throughput than overlay-only cognitive radio and 43% enhanced throughput than a hybrid cognitive radio system harvesting energy only from the ambient sources. However, increasing the throughput also increases computational burden on the secondary user, which may increase latency and energy requirements of the system. Index Terms-Access strategy, cognitive radio, energy harvesting, hybrid cognitive radio, POMDP, primary channel energy harvesting.
Network simulators have gained an increased importance in the research community to an extent tha... more Network simulators have gained an increased importance in the research community to an extent that approximately 11% of the research papers that appeared in the proceedings of leading international conferences used network simulators to test their claims. It is anticipated that due to the several advantages network simulators will become more prevalent in the research community in future. However, with the growing popularity of the network simulators, challenges in the form of consistent revelations about their inaccuracies have started to seriously question the use of such simulators and simulation based research. This paper attempts to answer the questions (1) How can assumptions/simplifications in modeling affect realism of simulations? (2) How credibility of simulation based research be improved?, and (3) What necessary steps must be taken to make network simulators credible? The paper provides deliberated recommendations for improving the authenticity of simulation based experiments. The authors believe that the discussion in this paper will greatly facilitate the repeatability of simulation based research and will help researchers to select the most suitable (credible) simulator.
Different cultivars of edible crops like tomato and carrot were explored for development of effic... more Different cultivars of edible crops like tomato and carrot were explored for development of efficient plant regeneration system. Efficient direct shoot regeneration system was developed from leaf disc in tomato cv. Moneymaker on medium containing MS salts, 1mgL -1 each of zeatin and IAA along with B5 vitamins comparable to efficient regeneration
ABSTRACT Introduction Posterior cruciate ligament (PCL) reconstruction using the remnant preservi... more ABSTRACT Introduction Posterior cruciate ligament (PCL) reconstruction using the remnant preserving technique may contribute to improve postoperative posterior stability, graft healing, and proprioception recovery. Although there have been several reports on remnant preserving PCL reconstruction, no study has yet evaluated the proprioceptive functions before and after PCL reconstruction with remnant preservation. The purpose of this study is to retrospectively evaluate the clinical outcomes and proprioceptive function after isolated single-bundle PCL reconstruction with remnant preservation for chronic PCL injuries. Hypothesis Isolated single-bundle PCL reconstruction with remnant preservation surgery for chronic PCL injuries provides satisfactory clinical outcomes and good recovery of the proprioceptive function. Methods Nineteen patients who had undergone isolated single-bundle PCL reconstruction with remnant preservation for chronic PCL injuries were followed-up for more than 2 years. The posterior laxity was measured by the gravity sag view, stress radiography and the KT-2000 knee arthrometer. The proprioceptive function was defined as the threshold to detect passive motion (TTDPM). Results The average Lysholm score significantly improved from 63.7 ± 13.2 preoperatively to 94.4 ± 4.6 at final follow-up. The postoperative posterior laxity significantly improved. Regarding TTDPM, there were no significant differences between the preoperative score and the score at every given time point, regardless of the starting angles and the moving directions of the knees. Conclusions The proprioceptive function, defined as TTDPM, is maintained after single-bundle PCL reconstruction with remnant preservation, and the postoperative clinical scores and posterior laxity significantly improve. Level of evidence Level IV, therapeutic case series.
Cells, scaffold, and growth factors are crucially important in regenerative medicine and tissue e... more Cells, scaffold, and growth factors are crucially important in regenerative medicine and tissue engineering. Progress in science and technology has enabled development of these three factors, with basic research being applied clinically. In the past decade, we have investigated tissue regeneration in animal models of musculoskeletal disorders by using cells, scaffold, and delivery systems which has been relatively easy to apply and develop in clinical settings. Moreover, microRNA (miRNA), which are important in biological processes and in the pathogenesis of human diseases, have been used in research on regenerative medicine. For the cell source, we focused on mesenchymal stem cells (MSC) and CD34 ? and CD133 ? cells as endothelial progenitor cells for regeneration of musculoskeletal organs. These cells are accessible and safe. For less invasive and more effective therapy, we developed a novel cell-delivery system using magnetic force to accumulate cells at a desired site. Furthermore, administration of synthetic miRNA could enhance tissue regeneration. In our studies, use of these cells combined with a cell-delivery system, miRNA, scaffold, and cytokines has led to effective regeneration of musculoskeletal tissues including cartilage, bone, ligaments, muscle, peripheral nerves, and spinal cord. The current and future objective is more effective and less invasive cell-based therapy with spatial control of transplanted cells by use of an external magnetic force. Analysis of efficiency, safety, and the mechanism of tissue regeneration by cells, scaffold, and miRNA will lead to more promising regenerative medicine, involving the development of a new generation of therapy. This review will focus on our regenerative medicine research, which focuses on clinical application of cells, scaffold, and miRNA.
ABSTRACT Far antero-medial (FAM) portal technique is usually used in our department in anterior c... more ABSTRACT Far antero-medial (FAM) portal technique is usually used in our department in anterior cruciate ligament (ACL) reconstruction when drilling the femoral tunnel. Although the FAM portal technique carrries potential risks, such as cartilage injury of the lateral femoral condyle, peroneal nerve injury and blow out of the lateral femoral condyle's posterior wall, these problems were resolved in a cadaveric study, in which 110°–120° knee flexion was recommended when drilling the femoral tunnel. However, there is a potential risk of injuring the cartilage of the medial femoral condyle especially when drilling the postero-lateral bundle. A new method is proposed to ensure that the femoral tunnel drilling does not damage the cartilage of the medial femoral condyle.
ABSTRACT In revision anterior cruciate ligament reconstruction (ACLR), the single-stage technique... more ABSTRACT In revision anterior cruciate ligament reconstruction (ACLR), the single-stage technique and the over-the-top route (OTTR) procedure were usually selected for cases where the bone tunnel cannot be created at an anatomical position due to tunnel enlargement and overlap with the mal-positioned tunnel of primary reconstruction. The purpose of this study was to evaluate the clinical results of revision single-bundle ACL reconstruction using OTTR procedure and to compare the clinical results of OTTR procedure with those of anatomical single bundle revision reconstruction (SBR).
ABSTRACT In this paper, uncertainty in the spectrum sensing arising from channel destructive effe... more ABSTRACT In this paper, uncertainty in the spectrum sensing arising from channel destructive effects such as shadowing and fading, is controlled by proposing a non-uniform reliability based cooperative spectrum sensing (CSS) technique. Channel conditions are quantified into non-uniform reliabilities which are assigned to users based on their congruence with the global observation. An identification tag (IT), assigned on the bases of correlation between secondary user’s local observation and the primary signal status, is used to detect malicious users (MU). In the proposed scheme, unreliable as well as malicious users (always busy, always free, and always opposite) are discarded from the network leading to improved inference accuracy. Simulation results show the advantage of our proposed scheme over the conventional CSS.
ABSTRACT In this paper, uncertainty in the spectrum sensing arising from channel destructive effe... more ABSTRACT In this paper, uncertainty in the spectrum sensing arising from channel destructive effects such as shadowing and fading, is controlled by proposing a non-uniform reliability based cooperative spectrum sensing (CSS) technique. Channel conditions are quantified into non-uniform reliabilities, which are assigned to users as their identification tags (IT), and are used by the fusion center to exclude the unreliable users from the global decision. IT is used to detect malicious users (MU). Two strategies have been proposed in this work to discard the unreliable as well as malicious users (of type always opposite and always busy) from the network which leads to improved inference accuracy. The simulation results show the effectiveness of our proposed strategies where our proposed strategies demonstrates better detection performance and consider fewer users than the conventional CSS and Chair-Varshney optimum rule, in the presence of malicious users.
In this paper, we consider a hybrid underlay-overlay cognitive radio with energy harvesting. In t... more In this paper, we consider a hybrid underlay-overlay cognitive radio with energy harvesting. In the considered system, secondary user can harvest energy from the primary user's signal as well as from the other ambient sources, such as solar, wind, vibration and so on. Energy is harvested from the primary user's signal when the primary channel is found in busy state. The secondary user either operates in one of the two transmission modes; overlay and underlay in order to maximize the throughput, remains in the sleep mode in order to conserve energy, or harvests energy from the primary channel in order to maximize the remaining energy. To maximize long-term throughput of the system, we propose an access strategy in which the partially observable Markov decision process framework is used to determine action of the secondary user, and energy threshold is used to determine the transmission mode (overlay or underlay) of secondary user. Simulations show that for certain values of the system parameters, the considered system provides 60% improved throughput than overlay-only cognitive radio and 43% enhanced throughput than a hybrid cognitive radio system harvesting energy only from the ambient sources. However, increasing the throughput also increases computational burden on the secondary user, which may increase latency and energy requirements of the system. Index Terms-Access strategy, cognitive radio, energy harvesting, hybrid cognitive radio, POMDP, primary channel energy harvesting.
Network simulators have gained an increased importance in the research community to an extent tha... more Network simulators have gained an increased importance in the research community to an extent that approximately 11% of the research papers that appeared in the proceedings of leading international conferences used network simulators to test their claims. It is anticipated that due to the several advantages network simulators will become more prevalent in the research community in future. However, with the growing popularity of the network simulators, challenges in the form of consistent revelations about their inaccuracies have started to seriously question the use of such simulators and simulation based research. This paper attempts to answer the questions (1) How can assumptions/simplifications in modeling affect realism of simulations? (2) How credibility of simulation based research be improved?, and (3) What necessary steps must be taken to make network simulators credible? The paper provides deliberated recommendations for improving the authenticity of simulation based experiments. The authors believe that the discussion in this paper will greatly facilitate the repeatability of simulation based research and will help researchers to select the most suitable (credible) simulator.
Different cultivars of edible crops like tomato and carrot were explored for development of effic... more Different cultivars of edible crops like tomato and carrot were explored for development of efficient plant regeneration system. Efficient direct shoot regeneration system was developed from leaf disc in tomato cv. Moneymaker on medium containing MS salts, 1mgL -1 each of zeatin and IAA along with B5 vitamins comparable to efficient regeneration
ABSTRACT Introduction Posterior cruciate ligament (PCL) reconstruction using the remnant preservi... more ABSTRACT Introduction Posterior cruciate ligament (PCL) reconstruction using the remnant preserving technique may contribute to improve postoperative posterior stability, graft healing, and proprioception recovery. Although there have been several reports on remnant preserving PCL reconstruction, no study has yet evaluated the proprioceptive functions before and after PCL reconstruction with remnant preservation. The purpose of this study is to retrospectively evaluate the clinical outcomes and proprioceptive function after isolated single-bundle PCL reconstruction with remnant preservation for chronic PCL injuries. Hypothesis Isolated single-bundle PCL reconstruction with remnant preservation surgery for chronic PCL injuries provides satisfactory clinical outcomes and good recovery of the proprioceptive function. Methods Nineteen patients who had undergone isolated single-bundle PCL reconstruction with remnant preservation for chronic PCL injuries were followed-up for more than 2 years. The posterior laxity was measured by the gravity sag view, stress radiography and the KT-2000 knee arthrometer. The proprioceptive function was defined as the threshold to detect passive motion (TTDPM). Results The average Lysholm score significantly improved from 63.7 ± 13.2 preoperatively to 94.4 ± 4.6 at final follow-up. The postoperative posterior laxity significantly improved. Regarding TTDPM, there were no significant differences between the preoperative score and the score at every given time point, regardless of the starting angles and the moving directions of the knees. Conclusions The proprioceptive function, defined as TTDPM, is maintained after single-bundle PCL reconstruction with remnant preservation, and the postoperative clinical scores and posterior laxity significantly improve. Level of evidence Level IV, therapeutic case series.
Cells, scaffold, and growth factors are crucially important in regenerative medicine and tissue e... more Cells, scaffold, and growth factors are crucially important in regenerative medicine and tissue engineering. Progress in science and technology has enabled development of these three factors, with basic research being applied clinically. In the past decade, we have investigated tissue regeneration in animal models of musculoskeletal disorders by using cells, scaffold, and delivery systems which has been relatively easy to apply and develop in clinical settings. Moreover, microRNA (miRNA), which are important in biological processes and in the pathogenesis of human diseases, have been used in research on regenerative medicine. For the cell source, we focused on mesenchymal stem cells (MSC) and CD34 ? and CD133 ? cells as endothelial progenitor cells for regeneration of musculoskeletal organs. These cells are accessible and safe. For less invasive and more effective therapy, we developed a novel cell-delivery system using magnetic force to accumulate cells at a desired site. Furthermore, administration of synthetic miRNA could enhance tissue regeneration. In our studies, use of these cells combined with a cell-delivery system, miRNA, scaffold, and cytokines has led to effective regeneration of musculoskeletal tissues including cartilage, bone, ligaments, muscle, peripheral nerves, and spinal cord. The current and future objective is more effective and less invasive cell-based therapy with spatial control of transplanted cells by use of an external magnetic force. Analysis of efficiency, safety, and the mechanism of tissue regeneration by cells, scaffold, and miRNA will lead to more promising regenerative medicine, involving the development of a new generation of therapy. This review will focus on our regenerative medicine research, which focuses on clinical application of cells, scaffold, and miRNA.
ABSTRACT Far antero-medial (FAM) portal technique is usually used in our department in anterior c... more ABSTRACT Far antero-medial (FAM) portal technique is usually used in our department in anterior cruciate ligament (ACL) reconstruction when drilling the femoral tunnel. Although the FAM portal technique carrries potential risks, such as cartilage injury of the lateral femoral condyle, peroneal nerve injury and blow out of the lateral femoral condyle's posterior wall, these problems were resolved in a cadaveric study, in which 110°–120° knee flexion was recommended when drilling the femoral tunnel. However, there is a potential risk of injuring the cartilage of the medial femoral condyle especially when drilling the postero-lateral bundle. A new method is proposed to ensure that the femoral tunnel drilling does not damage the cartilage of the medial femoral condyle.
ABSTRACT In revision anterior cruciate ligament reconstruction (ACLR), the single-stage technique... more ABSTRACT In revision anterior cruciate ligament reconstruction (ACLR), the single-stage technique and the over-the-top route (OTTR) procedure were usually selected for cases where the bone tunnel cannot be created at an anatomical position due to tunnel enlargement and overlap with the mal-positioned tunnel of primary reconstruction. The purpose of this study was to evaluate the clinical results of revision single-bundle ACL reconstruction using OTTR procedure and to compare the clinical results of OTTR procedure with those of anatomical single bundle revision reconstruction (SBR).
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