Rotorcraft research testing in the National Full-Scale Aerodynamics Complex at NASA Ames Research Center

The unique capabilities of the National Full-Scale Aerodynamics Complex (NFAC) for testing rotorcraft systems are described. The test facilities include the 40- by 80-Foot Wind Tunnel, the 80- by 120-Foot Wind Tunnel, and the Outdoor Aerodynamic Research Facility. The Ames 7- by 10-Foot Subsonic Wind Tunnel is also used in support of the rotor research programs conducted in the NFAC. Detailed descriptions of each of the facilities, with an emphasis on helicopter rotor test capability, are presented. The special purpose rotor test equipment used in conducting helicopter research is reviewed. Test rigs to operate full-scale helicopter main rotors, helicopter tail rotors, and tilting prop-rotors are available, as well as full-scale and small-scale rotor systems for use in various research programs. The test procedures used in conducting rotor experiments are discussed together with representative data obtained from previous test programs. Specific examples are given for rotor performance, loads, acoustics, system interactions, dynamic and aeroelastic stability, and advanced technology and prototype demonstration models

A critical analysis of research potential, challenges and future directives in industrial wireless sensor networks

In recent years, Industrial Wireless Sensor Networks (IWSNs) have emerged as an important research theme with applications spanning a wide range of industries including automation, monitoring, process control, feedback systems and automotive. Wide scope of IWSNs applications ranging from small production units, large oil and gas industries to nuclear fission control, enables a fast-paced research in this field. Though IWSNs offer advantages of low cost, flexibility, scalability, self-healing, easy deployment and reformation, yet they pose certain limitations on available potential and introduce challenges on multiple fronts due to their susceptibility to highly complex and uncertain industrial environments. In this paper a detailed discussion on design objectives, challenges and solutions, for IWSNs, are presented. A careful evaluation of industrial systems, deadlines and possible hazards in industrial atmosphere are discussed. The paper also presents a thorough review of the existing standards and industrial protocols and gives a critical evaluation of potential of these standards and protocols along with a detailed discussion on available hardware platforms, specific industrial energy harvesting techniques and their capabilities. The paper lists main service providers for IWSNs solutions and gives insight of future trends and research gaps in the field of IWSNs

Separation Framework: An Enabler for Cooperative and D2D Communication for Future 5G Networks

Soaring capacity and coverage demands dictate that future cellular networks need to soon migrate towards ultra-dense networks. However, network densification comes with a host of challenges that include compromised energy efficiency, complex interference management, cumbersome mobility management, burdensome signaling overheads and higher backhaul costs. Interestingly, most of the problems, that beleaguer network densification, stem from legacy networks' one common feature i.e., tight coupling between the control and data planes regardless of their degree of heterogeneity and cell density. Consequently, in wake of 5G, control and data planes separation architecture (SARC) has recently been conceived as a promising paradigm that has potential to address most of aforementioned challenges. In this article, we review various proposals that have been presented in literature so far to enable SARC. More specifically, we analyze how and to what degree various SARC proposals address the four main challenges in network densification namely: energy efficiency, system level capacity maximization, interference management and mobility management. We then focus on two salient features of future cellular networks that have not yet been adapted in legacy networks at wide scale and thus remain a hallmark of 5G, i.e., coordinated multipoint (CoMP), and device-to-device (D2D) communications. After providing necessary background on CoMP and D2D, we analyze how SARC can particularly act as a major enabler for CoMP and D2D in context of 5G. This article thus serves as both a tutorial as well as an up to date survey on SARC, CoMP and D2D. Most importantly, the article provides an extensive outlook of challenges and opportunities that lie at the crossroads of these three mutually entangled emerging technologies.Comment: 28 pages, 11 figures, IEEE Communications Surveys & Tutorials 201

Optimization of Natural Ventilation Design in Hot and Humid Climates Using Building Energy Simulation

This research aims to propose and explore natural ventilation schemes for the design of high-performance, non-residential buildings in hot and humid climates. Three such schemes were applied toward retrofitting the existing Hawai‘i Institute of Geophysics buildings on University of Hawai‘i at Mānoa (UHM) campus in Honolulu. The results were investigated by using parametric study and Airflow Network (AN) model, coupled with thermal model in EnergyPlus. Meanwhile, the number of discomfort hours, during the time the buildings are occupied and based on the adaptive thermal comfort, was used as a quantitative index for the performance of the natural ventilation design schemes. The results revealed that pure cross-ventilation is not a feasible mode to deliver adequate thermal comfort to the occupants, per an acceptable number of discomfort hours. However, with the supplementation of vertical ventilation ducts (shafts), the performance of natural ventilation design schemes significantly improved. In these cases, it was found that either ventilation ducts or ventilation windows can be completely closed, thus eliminating the need of one or the other in natural ventilation designs and therefore mitigating the potential for outdoor noise traveling into spaces through ventilation ducts and/or ventilation windows’ openings. This research presents my preliminary investigation toward finding the optimal scheme for natural ventilation design. After the scheme is chosen, the actual geometry of the ventilation ducts and ventilation windows, appropriate louvers and duct fittings, as well as their optimal aspect ratios, should be taken into consideration. For future research to be able to extend to incorporate a wider range of climate conditions, a hybrid ventilation approach integrating both mechanical and natural ventilation should be carried out. Moreover, further study of ventilation effectiveness, as per Computational Fluid Dynamics (CFD), is also recommended.This research aims to propose and explore natural ventilation schemes for the design of high-performance, non-residential buildings in hot and humid climates. Three such schemes were applied toward retrofitting the existing Hawai‘i Institute of Geophysics buildings on University of Hawai‘i at Mānoa (UHM) campus in Honolulu. The results were investigated by using parametric study and Airflow Network (AN) model, coupled with thermal model in EnergyPlus. Meanwhile, the number of discomfort hours, during the time the buildings are occupied and based on the adaptive thermal comfort, was used as a quantitative index for the performance of the natural ventilation design schemes. The results revealed that pure cross-ventilation is not a feasible mode to deliver adequate thermal comfort to the occupants, per an acceptable number of discomfort hours. However, with the supplementation of vertical ventilation ducts (shafts), the performance of natural ventilation design schemes significantly improved. In these cases, it was found that either ventilation ducts or ventilation windows can be completely closed, thus eliminating the need of one or the other in natural ventilation designs and therefore mitigating the potential for outdoor noise traveling into spaces through ventilation ducts and/or ventilation windows’ openings. This research presents my preliminary investigation toward finding the optimal scheme for natural ventilation design. After the scheme is chosen, the actual geometry of the ventilation ducts and ventilation windows, appropriate louvers and duct fittings, as well as their optimal aspect ratios, should be taken into consideration. For future research to be able to extend to incorporate a wider range of climate conditions, a hybrid ventilation approach integrating both mechanical and natural ventilation should be carried out. Moreover, further study of ventilation effectiveness, as per Computational Fluid Dynamics (CFD), is also recommended.This research aims to propose and explore natural ventilation schemes for the design of high-performance, non-residential buildings in hot and humid climates. Three such schemes were applied toward retrofitting the existing Hawai‘i Institute of Geophysics buildings on University of Hawai‘i at Mānoa (UHM) campus in Honolulu. The results were investigated by using parametric study and Airflow Network (AN) model, coupled with thermal model in EnergyPlus. Meanwhile, the number of discomfort hours, during the time the buildings are occupied and based on the adaptive thermal comfort, was used as a quantitative index for the performance of the natural ventilation design schemes. The results revealed that pure cross-ventilation is not a feasible mode to deliver adequate thermal comfort to the occupants, per an acceptable number of discomfort hours. However, with the supplementation of vertical ventilation ducts (shafts), the performance of natural ventilation design schemes significantly improved. In these cases, it was found that either ventilation ducts or ventilation windows can be completely closed, thus eliminating the need of one or the other in natural ventilation designs and therefore mitigating the potential for outdoor noise traveling into spaces through ventilation ducts and/or ventilation windows’ openings. This research presents my preliminary investigation toward finding the optimal scheme for natural ventilation design. After the scheme is chosen, the actual geometry of the ventilation ducts and ventilation windows, appropriate louvers and duct fittings, as well as their optimal aspect ratios, should be taken into consideration. For future research to be able to extend to incorporate a wider range of climate conditions, a hybrid ventilation approach integrating both mechanical and natural ventilation should be carried out. Moreover, further study of ventilation effectiveness, as per Computational Fluid Dynamics (CFD), is also recommended.This research aims to propose and explore natural ventilation schemes for the design of high-performance, non-residential buildings in hot and humid climates. Three such schemes were applied toward retrofitting the existing Hawai‘i Institute of Geophysics buildings on University of Hawai‘i at Mānoa (UHM) campus in Honolulu. The results were investigated by using parametric study and Airflow Network (AN) model, coupled with thermal model in EnergyPlus. Meanwhile, the number of discomfort hours, during the time the buildings are occupied and based on the adaptive thermal comfort, was used as a quantitative index for the performance of the natural ventilation design schemes. The results revealed that pure cross-ventilation is not a feasible mode to deliver adequate thermal comfort to the occupants, per an acceptable number of discomfort hours. However, with the supplementation of vertical ventilation ducts (shafts), the performance of natural ventilation design schemes significantly improved. In these cases, it was found that either ventilation ducts or ventilation windows can be completely closed, thus eliminating the need of one or the other in natural ventilation designs and therefore mitigating the potential for outdoor noise traveling into spaces through ventilation ducts and/or ventilation windows’ openings. This research presents my preliminary investigation toward finding the optimal scheme for natural ventilation design. After the scheme is chosen, the actual geometry of the ventilation ducts and ventilation windows, appropriate louvers and duct fittings, as well as their optimal aspect ratios, should be taken into consideration. For future research to be able to extend to incorporate a wider range of climate conditions, a hybrid ventilation approach integrating both mechanical and natural ventilation should be carried out. Moreover, further study of ventilation effectiveness, as per Computational Fluid Dynamics (CFD), is also recommended.This research aims to propose and explore natural ventilation schemes for the design of high-performance, non-residential buildings in hot and humid climates. Three such schemes were applied toward retrofitting the existing Hawai‘i Institute of Geophysics buildings on University of Hawai‘i at Mānoa (UHM) campus in Honolulu. The results were investigated by using parametric study and Airflow Network (AN) model, coupled with thermal model in EnergyPlus. Meanwhile, the number of discomfort hours, during the time the buildings are occupied and based on the adaptive thermal comfort, was used as a quantitative index for the performance of the natural ventilation design schemes. The results revealed that pure cross-ventilation is not a feasible mode to deliver adequate thermal comfort to the occupants, per an acceptable number of discomfort hours. However, with the supplementation of vertical ventilation ducts (shafts), the performance of natural ventilation design schemes significantly improved. In these cases, it was found that either ventilation ducts or ventilation windows can be completely closed, thus eliminating the need of one or the other in natural ventilation designs and therefore mitigating the potential for outdoor noise traveling into spaces through ventilation ducts and/or ventilation windows’ openings. This research presents my preliminary investigation toward finding the optimal scheme for natural ventilation design. After the scheme is chosen, the actual geometry of the ventilation ducts and ventilation windows, appropriate louvers and duct fittings, as well as their optimal aspect ratios, should be taken into consideration. For future research to be able to extend to incorporate a wider range of climate conditions, a hybrid ventilation approach integrating both mechanical and natural ventilation should be carried out. Moreover, further study of ventilation effectiveness, as per Computational Fluid Dynamics (CFD), is also recommended.This research aims to propose and explore natural ventilation schemes for the design of high-performance, non-residential buildings in hot and humid climates. Three such schemes were applied toward retrofitting the existing Hawai‘i Institute of Geophysics buildings on University of Hawai‘i at Mānoa (UHM) campus in Honolulu. The results were investigated by using parametric study and Airflow Network (AN) model, coupled with thermal model in EnergyPlus. Meanwhile, the number of discomfort hours, during the time the buildings are occupied and based on the adaptive thermal comfort, was used as a quantitative index for the performance of the natural ventilation design schemes. The results revealed that pure cross-ventilation is not a feasible mode to deliver adequate thermal comfort to the occupants, per an acceptable number of discomfort hours. However, with the supplementation of vertical ventilation ducts (shafts), the performance of natural ventilation design schemes significantly improved. In these cases, it was found that either ventilation ducts or ventilation windows can be completely closed, thus eliminating the need of one or the other in natural ventilation designs and therefore mitigating the potential for outdoor noise traveling into spaces through ventilation ducts and/or ventilation windows’ openings. This research presents my preliminary investigation toward finding the optimal scheme for natural ventilation design. After the scheme is chosen, the actual geometry of the ventilation ducts and ventilation windows, appropriate louvers and duct fittings, as well as their optimal aspect ratios, should be taken into consideration. For future research to be able to extend to incorporate a wider range of climate conditions, a hybrid ventilation approach integrating both mechanical and natural ventilation should be carried out. Moreover, further study of ventilation effectiveness, as per Computational Fluid Dynamics (CFD), is also recommended.This research aims to propose and explore natural ventilation schemes for the design of high-performance, non-residential buildings in hot and humid climates. Three such schemes were applied toward retrofitting the existing Hawai‘i Institute of Geophysics buildings on University of Hawai‘i at Mānoa (UHM) campus in Honolulu. The results were investigated by using parametric study and Airflow Network (AN) model, coupled with thermal model in EnergyPlus. Meanwhile, the number of discomfort hours, during the time the buildings are occupied and based on the adaptive thermal comfort, was used as a quantitative index for the performance of the natural ventilation design schemes. The results revealed that pure cross-ventilation is not a feasible mode to deliver adequate thermal comfort to the occupants, per an acceptable number of discomfort hours. However, with the supplementation of vertical ventilation ducts (shafts), the performance of natural ventilation design schemes significantly improved. In these cases, it was found that either ventilation ducts or ventilation windows can be completely closed, thus eliminating the need of one or the other in natural ventilation designs and therefore mitigating the potential for outdoor noise traveling into spaces through ventilation ducts and/or ventilation windows’ openings. This research presents my preliminary investigation toward finding the optimal scheme for natural ventilation design. After the scheme is chosen, the actual geometry of the ventilation ducts and ventilation windows, appropriate louvers and duct fittings, as well as their optimal aspect ratios, should be taken into consideration. For future research to be able to extend to incorporate a wider range of climate conditions, a hybrid ventilation approach integrating both mechanical and natural ventilation should be carried out. Moreover, further study of ventilation effectiveness, as per Computational Fluid Dynamics (CFD), is also recommended.This research aims to propose and explore natural ventilation schemes for the design of high-performance, non-residential buildings in hot and humid climates. Three such schemes were applied toward retrofitting the existing Hawai‘i Institute of Geophysics buildings on University of Hawai‘i at Mānoa (UHM) campus in Honolulu. The results were investigated by using parametric study and Airflow Network (AN) model, coupled with thermal model in EnergyPlus. Meanwhile, the number of discomfort hours, during the time the buildings are occupied and based on the adaptive thermal comfort, was used as a quantitative index for the performance of the natural ventilation design schemes. The results revealed that pure cross-ventilation is not a feasible mode to deliver adequate thermal comfort to the occupants, per an acceptable number of discomfort hours. However, with the supplementation of vertical ventilation ducts (shafts), the performance of natural ventilation design schemes significantly improved. In these cases, it was found that either ventilation ducts or ventilation windows can be completely closed, thus eliminating the need of one or the other in natural ventilation designs and therefore mitigating the potential for outdoor noise traveling into spaces through ventilation ducts and/or ventilation windows’ openings. This research presents my preliminary investigation toward finding the optimal scheme for natural ventilation design. After the scheme is chosen, the actual geometry of the ventilation ducts and ventilation windows, appropriate louvers and duct fittings, as well as their optimal aspect ratios, should be taken into consideration. For future research to be able to extend to incorporate a wider range of climate conditions, a hybrid ventilation approach integrating both mechanical and natural ventilation should be carried out. Moreover, further study of ventilation effectiveness, as per Computational Fluid Dynamics (CFD), is also recommended.This research aims to propose and explore natural ventilation schemes for the design of high-performance, non-residential buildings in hot and humid climates. Three such schemes were applied toward retrofitting the existing Hawai‘i Institute of Geophysics buildings on University of Hawai‘i at Mānoa (UHM) campus in Honolulu. The results were investigated by using parametric study and Airflow Network (AN) model, coupled with thermal model in EnergyPlus. Meanwhile, the number of discomfort hours, during the time the buildings are occupied and based on the adaptive thermal comfort, was used as a quantitative index for the performance of the natural ventilation design schemes. The results revealed that pure cross-ventilation is not a feasible mode to deliver adequate thermal comfort to the occupants, per an acceptable number of discomfort hours. However, with the supplementation of vertical ventilation ducts (shafts), the performance of natural ventilation design schemes significantly improved. In these cases, it was found that either ventilation ducts or ventilation windows can be completely closed, thus eliminating the need of one or the other in natural ventilation designs and therefore mitigating the potential for outdoor noise traveling into spaces through ventilation ducts and/or ventilation windows’ openings. This research presents my preliminary investigation toward finding the optimal scheme for natural ventilation design. After the scheme is chosen, the actual geometry of the ventilation ducts and ventilation windows, appropriate louvers and duct fittings, as well as their optimal aspect ratios, should be taken into consideration. For future research to be able to extend to incorporate a wider range of climate conditions, a hybrid ventilation approach integrating both mechanical and natural ventilation should be carried out. Moreover, further study of ventilation effectiveness, as per Computational Fluid Dynamics (CFD), is also recommended.This research aims to propose and explore natural ventilation schemes for the design of high-performance, non-residential buildings in hot and humid climates. Three such schemes were applied toward retrofitting the existing Hawai‘i Institute of Geophysics buildings on University of Hawai‘i at Mānoa (UHM) campus in Honolulu. The results were investigated by using parametric study and Airflow Network (AN) model, coupled with thermal model in EnergyPlus. Meanwhile, the number of discomfort hours, during the time the buildings are occupied and based on the adaptive thermal comfort, was used as a quantitative index for the performance of the natural ventilation design schemes. The results revealed that pure cross-ventilation is not a feasible mode to deliver adequate thermal comfort to the occupants, per an acceptable number of discomfort hours. However, with the supplementation of vertical ventilation ducts (shafts), the performance of natural ventilation design schemes significantly improved. In these cases, it was found that either ventilation ducts or ventilation windows can be completely closed, thus eliminating the need of one or the other in natural ventilation designs and therefore mitigating the potential for outdoor noise traveling into spaces through ventilation ducts and/or ventilation windows’ openings. This research presents my preliminary investigation toward finding the optimal scheme for natural ventilation design. After the scheme is chosen, the actual geometry of the ventilation ducts and ventilation windows, appropriate louvers and duct fittings, as well as their optimal aspect ratios, should be taken into consideration. For future research to be able to extend to incorporate a wider range of climate conditions, a hybrid ventilation approach integrating both mechanical and natural ventilation should be carried out. Moreover, further study of ventilation effectiveness, as per Computational Fluid Dynamics (CFD), is also recommended.This research aims to propose and explore natural ventilation schemes for the design of high-performance, non-residential buildings in hot and humid climates. Three such schemes were applied toward retrofitting the existing Hawai‘i Institute of Geophysics buildings on University of Hawai‘i at Mānoa (UHM) campus in Honolulu. The results were investigated by using parametric study and Airflow Network (AN) model, coupled with thermal model in EnergyPlus. Meanwhile, the number of discomfort hours, during the time the buildings are occupied and based on the adaptive thermal comfort, was used as a quantitative index for the performance of the natural ventilation design schemes. The results revealed that pure cross-ventilation is not a feasible mode to deliver adequate thermal comfort to the occupants, per an acceptable number of discomfort hours. However, with the supplementation of vertical ventilation ducts (shafts), the performance of natural ventilation design schemes significantly improved. In these cases, it was found that either ventilation ducts or ventilation windows can be completely closed, thus eliminating the need of one or the other in natural ventilation designs and therefore mitigating the potential for outdoor noise traveling into spaces through ventilation ducts and/or ventilation windows’ openings. This research presents my preliminary investigation toward finding the optimal scheme for natural ventilation design. After the scheme is chosen, the actual geometry of the ventilation ducts and ventilation windows, appropriate louvers and duct fittings, as well as their optimal aspect ratios, should be taken into consideration. For future research to be able to extend to incorporate a wider range of climate conditions, a hybrid ventilation approach integrating both mechanical and natural ventilation should be carried out. Moreover, further study of ventilation effectiveness, as per Computational Fluid Dynamics (CFD), is also recommended

Measurements and comparison of primary biological aerosol above and below a tropical forest canopy using a dual channel fluorescence spectrometer

Original article can be found at: http://www.atmos-chem-phys.net/10/issue10.html Copyright - the authors. Authors grant any third party the right to use the article freely as long as its original authors and citation details are identified. The article and any associated published material is distributed under the Creative Commons Attribution 3.0 License.Aerosol particle size distributions were measured below and above a tropical rainforest canopy in Borneo, Malaysia, in June/July 2008 using the WIBS-3: a single particle dual channel fluorescence spectrometer. Material in the size range 0.8–20 μm was characterized according to optical equivalent diameter (DP), morphology and fluorescence at 310–400 nm and 400–600 nm following excitation at 280 nm and 370 nm respectively. Particles fluorescent after both excitations are likely to be fluorescent primary biological aerosol particles (FBAP). Measured FBAP number concentration (NFBAP) at both sites exhibited clear diurnal cycles. The largest variability was observed in the understorey, where NFBAP reached a minimum of 50–100 L−1 in late morning. In mid afternoon it exhibited strong transient fluctuations as large as 4000 L−1 that were followed by sustained concentrations of 1000–2500 L−1 that reduced steadily between midnight and sunrise. Above the canopy FBAP number ranged from 50–100 L−1 during the daytime to 200–400 L−1 at night but did not exhibit the transient enhancements seen in the understorey. The strong FBAP fluctuations were attributed to the release of fungal spores below the canopy and appeared to be linked to elevated relative humidity. The mean FBAP number fraction in the size range 0.8 μm<DP<20 μm was 55% in the understorey and 28% above canopy. A size mode at 2 μm<DP<4 μm appears at both sites and is primarily FBAP, which dominated the coarse (DP≥2.5 μm) number concentration at both sites, accounting for 75% in the understorey and 57% above the canopy. In contrast, the concentration of non-fluorescent particles (NNON) at both sites was typically 200–500 L−1, the majority of which occupied a size mode at 0.8<DP<1.5 μm. Enhanced understorey NNON was observed daily in mid-afternoon and also at midday on three occasions: the former coincided with the FBAP enhancements and measured approximately 10% of their magnitude; the latter occurred independently of the NFBAP diurnal cycle and comprised particles smaller than 2 μm. Particle diameter of 3–5 μm is consistent with smaller fungal spores, though absolute identification of biological species is not possible with the UV-LIF technique. Based on the measured FBAP and non-fluorescent particle abundances and their observed recovery times following rain showers, FBAP originated beneath the canopy while the non-fluorescent material was transported from further away. It is concluded that these separate sources contributed the majority of the aerosol measured by the WIBS-3 at both sites.Peer reviewe

Packet Loss in Terrestrial Wireless and Hybrid Networks

The presence of both a geostationary satellite link and a terrestrial local wireless link on the same path of a given network connection is becoming increasingly common, thanks to the popularity of the IEEE 802.11 protocol. The most common situation where a hybrid network comes into play is having a Wi-Fi link at the network edge and the satellite link somewhere in the network core. Example of scenarios where this can happen are ships or airplanes where Internet connection on board is provided through a Wi-Fi access point and a satellite link with a geostationary satellite; a small office located in remote or isolated area without cabled Internet access; a rescue team using a mobile ad hoc Wi-Fi network connected to the Internet or to a command centre through a mobile gateway using a satellite link. The serialisation of terrestrial and satellite wireless links is problematic from the point of view of a number of applications, be they based on video streaming, interactive audio or TCP. The reason is the combination of high latency, caused by the geostationary satellite link, and frequent, correlated packet losses caused by the local wireless terrestrial link. In fact, GEO satellites are placed in equatorial orbit at 36,000 km altitude, which takes the radio signal about 250 ms to travel up and down. Satellite systems exhibit low packet loss most of the time, with typical project constraints of 10−8 bit error rate 99% of the time, which translates into a packet error rate of 10−4, except for a few days a year. Wi-Fi links, on the other hand, have quite different characteristics. While the delay introduced by the MAC level is in the order of the milliseconds, and is consequently too small to affect most applications, its packet loss characteristics are generally far from negligible. In fact, multipath fading, interference and collisions affect most environments, causing correlated packet losses: this means that often more than one packet at a time is lost for a single fading even

Optimization of the overall success probability of the energy harvesting cognitive wireless sensor networks

Wireless energy harvesting can improve the performance of cognitive wireless sensor networks (WSNs). This paper considers radio frequency (RF) energy harvesting from transmissions in the primary spectrum for cognitive WSNs. The overall success probability of the energy harvesting cognitive WSN depends on the transmission success probability and energy success probability. Using the tools from stochastic geometry, we show that the overall success probability can be optimized with respect to: 1) transmit power of the sensors; 2) transmit power of the primary transmitters; and 3) spatial density of the primary transmitters. In this context, an optimization algorithm is proposed to maximize the overall success probability of the WSNs. Simulation results show that the overall success probability and the throughput of the WSN can be significantly improved by optimizing the aforementioned three parameters. As RF energy harvesting can also be performed indoors, hence, our solution can be directly applied to the cognitive WSNs that are installed in smart buildings