Radio spectrum for wireless communications is a finite resource whose allocation to different tec... more Radio spectrum for wireless communications is a finite resource whose allocation to different technologies and application areas is governed by regulatory bodies. Radio spectrum has enormous economic value, which at- tracts many potential wireless operators. One of the functions of the regulators is to assign the available radio spectrum to operators. Spectrum auctioning became a favorable tool for selecting operators and assigning bandwidth to bidders. Many auctioning methods have been proposed in order to achieve ef- ficient and fair allocation. It is common to decide before the auction begins on the number of operators that will be permitted to operate in each geographic area. We develop a model of the net revenues of an operator as a function of the number of operators that are permitted to operate in a given area. It is demonstrated through numerical examples that a priori decisions can lead to significant reductions in the value of the allocated spectrum. An improved auctionin...
International Journal of Information Science and Management, 2012
The last few years have seen an explosion in the deployment and use of the Internet, networking a... more The last few years have seen an explosion in the deployment and use of the Internet, networking and telecommunication technologies. This was followed by significant increases in the speed and capacity of computing, for example Petaflop supercomputers are becoming common. We will examine some of the developments; explain their importance and potential impact. Many forecasts and predictions have been made about the impact of the increases of computing capacity and the growth of the Internet and the world wide web. In this talk we will introduce some of the favorite predictions and will analyze the possibilities for their realization in the long run. The analysis shows that there exist hard limits on the growth of the Internet and the increase in computing capacity. They prove that it is unlikely that some of the predictions will hold in the long run. The restrictions are based on basic physical and economic limitations, which generate tight bounds on the realization of such prediction...
Fraud on the Internet is develop-ing into a major issue for con-sumers, businesses, and governmen... more Fraud on the Internet is develop-ing into a major issue for con-sumers, businesses, and governments [1, 6, 10]. The Financial Times in 2003 called online fraud “an epidemic of huge and rapidly growing pro-portions ” and noted the inci-dence of fraud was 20 times higher online than offline [12]. The complaints of online fraud registered at the IC3 Web site— which is jointly sponsored by the
Objectives: Assessing the methodology of using blood pressure (BP) variation at different arm cuf... more Objectives: Assessing the methodology of using blood pressure (BP) variation at different arm cuff heights for the determination of the slope characterizing the linear relationship between systolic BP (SBP) and diastolic BP (DBP), which was found to have prognostic significance when determined by 24-hour ambulatory monitoring. Methods: The study population included 46 healthy subjects: M/F 25/21; age 52 ± 15 year; BP 111 ± 16/61 ± 8 mmHg. BP was measured in the sitting position with an upper-arm cuff using a digital BP monitor. BP measurements (n = 7 to 9) performed consecutively at arm postures at 3–4 different cuff center heights varying between heart to head level. At each posture, the (flexed) arm was either self-supported (17 patients) or supported comfortably by a stand with an arm support adjustable at selectable levels (29 patients). Between measurements, the arm rested at the heart level for at least about 30 sec. The test duration was 15–20 minutes. Variability of SBP and DBP was expressed by the standard deviations of SBP, SDs, and DBP, SDd, respectively. Following the principles of symmetric regression analysis, SBP-on-DBP slope was estimated by SDs/SDd, called BP Variability Ratio (BPVR). Results: Mean ± SD of the BP variability range (twice the SD values) was 20 ± 6/16 ± 4 mmHg. SBP-DBP relationship was highly linear (r = 0.952 ± 0.036). SBP-on-DBP slope was 1.18 ± 0.28 with 5 ± 2% error of determination. Data were insensitive to the use of the stand. Conclusion: Measuring BP at different arm heights is a simple and fast way for determining the SBP-on-DBP slope. While BP variability range and determination accuracy is comparable to the 24-hour ambulatory-based method, the present method is relatively “instantaneous” regarding circulatory status and potentially applicable for non-dipping and short term response to interventions, performed in resting conditions and BP variability is created passively by gravitation, hence relative stability of the arterial factor. This could also enhance reproducibility. However, outcomes variation over time, comparability with ambulatory method and prognostic significance remains to be evaluated.
vascular effects and are based on population reference data and oversimplified boundary condition... more vascular effects and are based on population reference data and oversimplified boundary conditions. Because contractile properties of the heart may play a role as well, we investigated by means of a computational model the isolated and combined influences of cardiac properties as well as vascular stiffening on the central BP waveform. A model of the circulation (Arts et al.2005, AJP-Heart) was used to simulate central and peripheral BP waveforms from the left ventricle (LV) to femoral and radial arteries. We investigated the effect on BP waveforms of 1) a 50% reduction in the shortening velocity (v-s) of LV sarcomeres and 2) a vascular stiffness increase, corresponding to an increase in carotid-femoral pulse wave velocity from 8.6m/s to 10.2m/s. Central BP waveforms were characterized using augmentation index (AIx, based on the 2nd derivative) and pulse pressure (PP). We obtained realistic BP waveforms for LV, central and peripheral vessels. Reducing v-s (all else equal) caused AIx to increase from respectively 16% (PPZ60mmHg) to 30% (PPZ60mmHg). Vascular stiffening (all else equal) resulted in an AIx increase from 16% to 36% and an increase in PP from 60 to 100mmHg. Combined reduced v and vascular stiffening resulted in an AIx of 42% with a PP of 80mmHg. Not only vascular, but also cardiac properties influence the central BP waveform. We conclude that heart-vessel interaction should be considered in pulse wave analysis.
We hypothesized that slow and regular breathing may reduce blood pressure (BP). Breathing pattern... more We hypothesized that slow and regular breathing may reduce blood pressure (BP). Breathing pattern modification can be achieved hy patients at home using a novel therepeutic device BIM (breathing with intemctivelyanUrolled music pettems). The study objectives were to eveluate the BP response to BIM-guided breathing exercises in e double-blinded randomized study with an active control. The study population included 65 hypertensives, 31 males end 34 females from 3 family practice clinics. Patients were aged 25-75 years with uncontrolled BP (Z stegel), either unmedicated or medicated with anti-hypertensive drugs with no dose change for 2 months prior to end during the study. Randomization wes to BIM or W&men (listening to similar quiet music). The devices were used daily for IO minutes at home for 8 weeks. BP w checked weekly at the clinic using standard sphyngmomanometers. l'bra to five consecutive readings were taken in tbe sitting position. The design eaabled double blinding. BP wes also measured 6 months atler the end of the trial. Baseline characteristics for BIM W&man groups were, respectively, N 32 33, age-58 57 years, %meles 56% 39%,
Computer communication networks and telecommunication systems are growing at an explosive rate. S... more Computer communication networks and telecommunication systems are growing at an explosive rate. Some of the major factors influencing this phenomenal growth rate have been technology driven, deregulation of the telecommunication industry and the breakup of AT&T, product ...
... utilize information about the multi-echelon configuration or the cost structure, have been de... more ... utilize information about the multi-echelon configuration or the cost structure, have been devised ... 5 is devoted to developing tight lower bounds to the optimal solution, and ?6 ... It is shown that theproblem can also be formulated as a minimum cost network flow problem subject to ...
Radio spectrum for wireless communications is a finite resource whose allocation to different tec... more Radio spectrum for wireless communications is a finite resource whose allocation to different technologies and application areas is governed by regulatory bodies. Radio spectrum has enormous economic value, which at- tracts many potential wireless operators. One of the functions of the regulators is to assign the available radio spectrum to operators. Spectrum auctioning became a favorable tool for selecting operators and assigning bandwidth to bidders. Many auctioning methods have been proposed in order to achieve ef- ficient and fair allocation. It is common to decide before the auction begins on the number of operators that will be permitted to operate in each geographic area. We develop a model of the net revenues of an operator as a function of the number of operators that are permitted to operate in a given area. It is demonstrated through numerical examples that a priori decisions can lead to significant reductions in the value of the allocated spectrum. An improved auctionin...
International Journal of Information Science and Management, 2012
The last few years have seen an explosion in the deployment and use of the Internet, networking a... more The last few years have seen an explosion in the deployment and use of the Internet, networking and telecommunication technologies. This was followed by significant increases in the speed and capacity of computing, for example Petaflop supercomputers are becoming common. We will examine some of the developments; explain their importance and potential impact. Many forecasts and predictions have been made about the impact of the increases of computing capacity and the growth of the Internet and the world wide web. In this talk we will introduce some of the favorite predictions and will analyze the possibilities for their realization in the long run. The analysis shows that there exist hard limits on the growth of the Internet and the increase in computing capacity. They prove that it is unlikely that some of the predictions will hold in the long run. The restrictions are based on basic physical and economic limitations, which generate tight bounds on the realization of such prediction...
Fraud on the Internet is develop-ing into a major issue for con-sumers, businesses, and governmen... more Fraud on the Internet is develop-ing into a major issue for con-sumers, businesses, and governments [1, 6, 10]. The Financial Times in 2003 called online fraud “an epidemic of huge and rapidly growing pro-portions ” and noted the inci-dence of fraud was 20 times higher online than offline [12]. The complaints of online fraud registered at the IC3 Web site— which is jointly sponsored by the
Objectives: Assessing the methodology of using blood pressure (BP) variation at different arm cuf... more Objectives: Assessing the methodology of using blood pressure (BP) variation at different arm cuff heights for the determination of the slope characterizing the linear relationship between systolic BP (SBP) and diastolic BP (DBP), which was found to have prognostic significance when determined by 24-hour ambulatory monitoring. Methods: The study population included 46 healthy subjects: M/F 25/21; age 52 ± 15 year; BP 111 ± 16/61 ± 8 mmHg. BP was measured in the sitting position with an upper-arm cuff using a digital BP monitor. BP measurements (n = 7 to 9) performed consecutively at arm postures at 3–4 different cuff center heights varying between heart to head level. At each posture, the (flexed) arm was either self-supported (17 patients) or supported comfortably by a stand with an arm support adjustable at selectable levels (29 patients). Between measurements, the arm rested at the heart level for at least about 30 sec. The test duration was 15–20 minutes. Variability of SBP and DBP was expressed by the standard deviations of SBP, SDs, and DBP, SDd, respectively. Following the principles of symmetric regression analysis, SBP-on-DBP slope was estimated by SDs/SDd, called BP Variability Ratio (BPVR). Results: Mean ± SD of the BP variability range (twice the SD values) was 20 ± 6/16 ± 4 mmHg. SBP-DBP relationship was highly linear (r = 0.952 ± 0.036). SBP-on-DBP slope was 1.18 ± 0.28 with 5 ± 2% error of determination. Data were insensitive to the use of the stand. Conclusion: Measuring BP at different arm heights is a simple and fast way for determining the SBP-on-DBP slope. While BP variability range and determination accuracy is comparable to the 24-hour ambulatory-based method, the present method is relatively “instantaneous” regarding circulatory status and potentially applicable for non-dipping and short term response to interventions, performed in resting conditions and BP variability is created passively by gravitation, hence relative stability of the arterial factor. This could also enhance reproducibility. However, outcomes variation over time, comparability with ambulatory method and prognostic significance remains to be evaluated.
vascular effects and are based on population reference data and oversimplified boundary condition... more vascular effects and are based on population reference data and oversimplified boundary conditions. Because contractile properties of the heart may play a role as well, we investigated by means of a computational model the isolated and combined influences of cardiac properties as well as vascular stiffening on the central BP waveform. A model of the circulation (Arts et al.2005, AJP-Heart) was used to simulate central and peripheral BP waveforms from the left ventricle (LV) to femoral and radial arteries. We investigated the effect on BP waveforms of 1) a 50% reduction in the shortening velocity (v-s) of LV sarcomeres and 2) a vascular stiffness increase, corresponding to an increase in carotid-femoral pulse wave velocity from 8.6m/s to 10.2m/s. Central BP waveforms were characterized using augmentation index (AIx, based on the 2nd derivative) and pulse pressure (PP). We obtained realistic BP waveforms for LV, central and peripheral vessels. Reducing v-s (all else equal) caused AIx to increase from respectively 16% (PPZ60mmHg) to 30% (PPZ60mmHg). Vascular stiffening (all else equal) resulted in an AIx increase from 16% to 36% and an increase in PP from 60 to 100mmHg. Combined reduced v and vascular stiffening resulted in an AIx of 42% with a PP of 80mmHg. Not only vascular, but also cardiac properties influence the central BP waveform. We conclude that heart-vessel interaction should be considered in pulse wave analysis.
We hypothesized that slow and regular breathing may reduce blood pressure (BP). Breathing pattern... more We hypothesized that slow and regular breathing may reduce blood pressure (BP). Breathing pattern modification can be achieved hy patients at home using a novel therepeutic device BIM (breathing with intemctivelyanUrolled music pettems). The study objectives were to eveluate the BP response to BIM-guided breathing exercises in e double-blinded randomized study with an active control. The study population included 65 hypertensives, 31 males end 34 females from 3 family practice clinics. Patients were aged 25-75 years with uncontrolled BP (Z stegel), either unmedicated or medicated with anti-hypertensive drugs with no dose change for 2 months prior to end during the study. Randomization wes to BIM or W&men (listening to similar quiet music). The devices were used daily for IO minutes at home for 8 weeks. BP w checked weekly at the clinic using standard sphyngmomanometers. l'bra to five consecutive readings were taken in tbe sitting position. The design eaabled double blinding. BP wes also measured 6 months atler the end of the trial. Baseline characteristics for BIM W&man groups were, respectively, N 32 33, age-58 57 years, %meles 56% 39%,
Computer communication networks and telecommunication systems are growing at an explosive rate. S... more Computer communication networks and telecommunication systems are growing at an explosive rate. Some of the major factors influencing this phenomenal growth rate have been technology driven, deregulation of the telecommunication industry and the breakup of AT&T, product ...
... utilize information about the multi-echelon configuration or the cost structure, have been de... more ... utilize information about the multi-echelon configuration or the cost structure, have been devised ... 5 is devoted to developing tight lower bounds to the optimal solution, and ?6 ... It is shown that theproblem can also be formulated as a minimum cost network flow problem subject to ...
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Papers by Bezalel Gavish