Multiple Deployment Research Articles

Utilizing a Test Lab For Wireless Medical Devices

Changes in healthcare suggest that more and more medical devices will begin to utilize the information technology (IT) network infrastructure in the hospital, particularly the wireless network. Due to the increased risk of operating medical devices on the converged wireless IT network, there are multiple steps required to safely and effectively implement these types of devices. A key component of the implementation should be to perform testing of wireless devices for interference and functionality. In order to perform this testing, development of a test environment within the hospital is required. While recent focus has been on electromagnetic interference and the risk assessment and mitigation via IEC 80001-1— the new standard for the application of risk management for IT networks incorporating medical devices—more progress is needed in the development of a test lab and performance of testing within the hospital environment. There are many potential benefits of deploying medical devices on the wireless network; however, there are multiple risks, including loss of data or missed patient alarm notification due to a loss of wireless network connectivity. Testing can be vital in identifying and developing mitigations for these risks. Creating the Lab In order to create a test lab, a location first must be selected. In theory, an ideal wireless test environment would be shielded from all external sources of radio frequency (RF) interference. To achieve this goal, physical space and a substantial budget would be required. A stand-alone wireless network infrastructure would have to be developed in this shielded space to enable the connection and testing of any wireless medical devices. This type of test environment is impractical for clinical engineering use due to resource constraints and the inadequacy for realistic simulation of the true deployment environment. A more realistic and beneficial location to create the test lab would be a clinical engineering shop or a storage area in the basement of the hospital. The value of this type of location is that the physical space is relatively distant from clinical floors, thereby limiting the interference between the current patient-care equipment and the test lab and reducing the potential risk to either the device under test or to the devices on the clinical floor. It is also advantageous to be in the hospital in order to utilize a segregated portion of the network infrastructure that is already in place. Also, although a test lab in this environment would not be totally isolated About the Author

Intrusion detection in a [formula omitted]-Gaussian distributed wireless sensor network

Random sensor deployment is of crucial importance for intrusion detection applications using a wireless sensor network (WSN) in hostile and dangerous environments. A uniform random WSN fails to detect a moving intruder if it starts inside the network domain and close to the target. A Gaussian distributed WSN cannot effectively detect the intruder if it starts from the network boundary. In view of this, this paper introduces a novel k -Gaussian deployment strategy to leverage the advantages of both uniform and Gaussian random sensor deployment for efficient and effective intrusion detection. The key idea is to employ multiple deployment points in the area of interest and a subset of the total sensors are deployed around each deployment point following a Gaussian distribution and form a k -Gaussian distributed WSN. Is the k -Gaussian deployment strategy always better than the uniform and Gaussian deployment strategy and how much better for intrusion detection in WSNs is therefore a must-answer question. This work explores the intrusion detection problem in a k -Gaussian distributed WSN under the multi-level probabilistic sensing models theoretically and by simulations. Matching between the analytical results and simulation outcomes validates the correctness of the modeling and analysis, and the effectiveness of the proposed approach is demonstrated by comparing with the counterpart uniform and Gaussian sensor deployment strategies under the considered scenarios. This work provides insights into random sensor deployment for efficient intrusion detection.

International standardization of cognitive radio systems

The current radio environment is characterized by its heterogeneity. Different aspects of this heterogeneity include multiple operators and services, various radio access technologies, different network topologies, a broad range of radio equipment, and multiple frequency bands. Such an environment has a lot of technical and business opportunities. Examples are joint management of several radio access networks within one operator to balance load of these networks, detecting and using unused spectrum in the allocated frequency bands without interrupting the operation of the primary users of such frequency bands, and spectrum trading between several operators. To exploit such opportunities, the concept of cognitive radio system has been developed. Many CRS usage scenarios and business cases are possible. This has triggered a lot of standardization activity at all levels, including in the International Telecommunication Union, IEEE, European Telecommunications Standards Institute, and European Association for Standardizing Information and Communication Systems; each of these organizations is considering multiple CRS deployment scenarios and business directions. This article describes the current concept of the CRS and shows the big picture of international standardization of the CRS. Understanding of these standardization activities is very important for both academia and industry in order to select important research topics and promising business directions.

Multiple-Robot Systems for USAR: Key Design Attributes and Deployment Issues

The interaction between humans and robots is undergoing an evolution. Progress in this evolution means that humans are close to robustly deploying multiple robots. Urban search and rescue (USAR) can benefit greatly from such capability. The review shows that with state of the art artificial intelligence, robots can work autonomously but still require human supervision. It also shows that multiple robot deployment (MRD) is more economical, shortens mission durations, adds reliability as well as addresses missions impossible with one robot and payload constraints. By combining robot autonomy and human supervision, the benefits of MRD can be applied to USAR while at the same time minimizing human exposure to danger. This is achieved with a single-human multiple-robot system (SHMRS). However, designers of the SHMRS must consider key attributes such as the size, composition and organizational structure of the robot collective. Variations in these attributes also induce fluctuations in issues within SHMRS deployment such as robot communication and computational load as well as human cognitive workload and situation awareness (SA). Research is essential to determine how the attributes can be manipulated to mitigate these issues while meeting the requirements of the USAR mission.

Optimization of multiple gateway deployment for underwater acoustic sensor networks

This research aims to develop novel technologies to efficiently integrate wireless communication networks and Underwater Acoustic Sensor Networks (UASNs). Surface gateway deployment is one of the key techniques for connecting two networks with different channels. In this work, we propose an optimization method based on the genetic algorithm for surface gateway deployment, design a novel transmission mechanism-simultaneous transmission, and realize two efficient routing algorithms that achieve minimal delay and payload balance among sensor nodes. We further develop an analytic model to study the delay, energy consumption and packet loss ratio of the network. Our simulation results verify the effectiveness of the model, and demonstrate that the technique of multiple gateway deployment and the mechanism of simultaneous transmission can effectively reduce network delay, energy consumption and packet loss rate.

Experimental Results in Multi-UAV Coordination for Disaster Management and Civil Security Applications

This paper describes a multi-UAV distributed decisional architecture developed in the framework of the AWARE Project together with a set of tests with real Unmanned Aerial Vehicles (UAVs) and Wireless Sensor Networks (WSNs) to validate this approach in disaster management and civil security applications. The paper presents the different components of the AWARE platform and the scenario in which the multi-UAV missions were carried out. The missions described in this paper include surveillance with multiple UAVs, sensor deployment and fire threat confirmation. In order to avoid redundancies, instead of describing the operation of the full architecture for every mission, only non-overlapping aspects are highlighted in each one. Key issues in multi-UAV systems such as distributed task allocation, conflict resolution and plan refining are solved in the execution of the missions.

A coordinated multiple channel assignment scheme and AP deployment for channel reuse in metropolitan scale wireless networks

In a wireless network, when a single channel is employed, hidden terminal and radio interference problems may occur. The two problems are the main factors that cause low network throughput. In fact, the hidden node problem results from radio interference. Up to the present, many researchers have used multi-channel schemes to solve the interference problem. However, a multi-channel system causes other problems, e.g., the multi-channel hidden terminal problem, and the channel assignment problem. Actually, a well-defined channel assignment can effectively solve the former problem. Therefore, in this paper, we propose a multi-channel assignment system, called a corona- oriented multi-channel assignment system (COMAS for short), which as a metropolitan scale system coordinates channel usage for wireless networks to mitigate radio interference among APs and nodes so as to improve network throughput and efficiency, particularly when many nodes are connected to APs. In the COMAS, APs are deployed as concentric circles, named coronas, and channels are grouped and then allocated to coronas. We also cluster APs into groups, and schedule available channels to avoid radio interference and multi-channel hidden terminal problems among adjacent AP groups and among APs in a group. Simulation results show that the COMAS can effectively improve wireless-network throughput, drop rate, packet delivery delay and jitter.

From versatility to auto-adaptation of the medium access control in wireless sensor networks

Recent deployments of wireless sensor networks have targeted challenging monitoring and surveillance applications. The medium access control being the main source of energy wastage, energy-efficiency has always been kept in mind while designing the communication stack embedded in spread sensors. Especially, versatile protocols have emerged to offer a suitable solution over multiple deployment characteristics. In this study, we observe to what extent versatility applies to dynamic scenarios in which communications do not respect specific communication paradigms. We first provide a performance evaluation of two well-reputed versatile protocols (B-MAC (Polastre et al., 2004 [17]) and X-MAC (Buettner et al., 2006 [4])) under the conditions of such a scenario. The obtained results convinced us to propose more than versatility and pre-configured solutions, that is auto-adaptation. We then introduce the main contribution of this paper, an auto-adaptive algorithm that allows one to adjust the previously mentioned protocols while the network is operating. We analyze to what extent it outperforms the previously obtained results.

Constrained multiple deployment problem in wireless sensor networks with guaranteed lifetimes

We aimed to deploy wireless sensor networks with guaranteed lifetimes for outdoor monitoring projects. The provision of a guaranteed lifetime has rarely been studied in previous deployment problems. The use of battery packs as the power source for sensors is common in many applications involving outdoor wireless sensor networks (WSNs). Because unified battery power is unable to provide both efficient collection and balance workload, we address the deployment procedure by considering adjustable battery packs. The key issue is determining the minimum number of battery packs required to guarantee both the system efficiency and lifetime. We formulate a constrained multiple deployment problem with energy models of the battery energy budget and sensor operations. The optimal solution is obtained using integer linear programming. We derived a lower bound of the deployment cost in terms of the number of battery packs. Due to the high time complexity for solving the optimal solution, we also propose two heuristics with polynomial-time complexity: (1) a battery-aware routing algorithm that selects routing paths based on consideration of the battery usage, and (2) a refinement procedure to improve existing WSN deployments by adjusting traffic in order to reduce the cost. Theoretical analyses of the proposed algorithms revealed their time complexity. We performed extensive simulations to evaluate the proposed algorithms in terms of the deployment cost and residual energy. The results show that our algorithm generates deployments close to the lower bound.

The Effect of Argon Gas Pressure on Ice Ball Size and Rate of Formation

Contemporary cryoablation technology utilizes the Joule-Thomson effect, defined as a change in temperature that results from expansion of a nonideal gas through an orifice or other restriction. We evaluated the effect of initial gas tank pressures on freezing dynamics in a single-probe model and in a multiprobe model using contemporary cryoablation technology. Cryoablation trials were performed in a standardized system of transparent gelatin molds at 25°C. Two sets of trials were performed. The first trial evaluated temperature and ice ball size for a given tank pressure when a single needle was deployed. The second trial recorded ice ball temperatures for each probe when multiple probes were fired simultaneously. Trial 1: The rate of temperature change is directly related to the initial pressure of the gas being released, and the group with the highest starting pressures reached the lowest mean temperature and had the largest mean ice ball size (p < 0.01). Trail 2: Multiple-probe ablation did not affect the rate of temperature change or final temperature compared with firing a single probe (p > 0.7). In accordance with the Joule-Thomson effect, higher initial gas pressures used for cryoablation in a transparent gel model demonstrate statistically significant lower temperatures, faster decreases in temperature, and formation of larger ice balls than lower gas pressures do. With contemporary technology, multiple simultaneous cryoprobe deployment does not compromise individual probe efficacy. The use of higher initial tank pressures will theoretically help future cryoprobes be more effective, creating a greater volume of cell necrosis and a smaller indeterminate zone.

Rapidly installed temporary gauging for hurricane waves and surge, and application to Hurricane Gustav

Hurricanes can produce extreme nearshore waves and surge, but permanent gauging stations are often much sparser than is desired. This paper describes the rationale behind and outline for rapidly installed temporary coastal gauges, and presents results during Hurricane Gustav (2008). Within 48 h prior to landfall, twenty self-recording pressure gauges were deployed in depths of 1.4–23 m over more than 700 km of coastline, using helicopters to cover the large distances. Results showed a complex picture that was strongly dependent on location. East of the Mississippi Delta, open coast waves were large, and surge reached 3.8 m NAVD88 in marshes. West of the delta but near landfall, waves and surge were generally smaller as the river levees blocked flow from East to West. West of landfall, both waves and surge were very small and the most prominent feature was a water level drawdown that reached 1.5 m. Wave spectra varied strongly depending both on location and time from landfall. This type of rapid gauging program is straightforward to duplicate: with multiple localized deployment centers to ensure coverage, dense nearshore hurricane wave and surge records could increase substantially in the future.

Influence of Measurement Equipment on the Uncertainty of Performance Data from Test Loops for Concentrating Solar Collectors

Parabolic trough concentrating collectors play a major role in the energy efficiency and economics of concentrating solar power plants. Therefore, existing collector systems are constantly enhanced and new types were developed. Thermal performance testing is one step generally required in the course of their testing and qualification. For outdoor tests of prototypes, a heat transfer fluid loop (single collector or entire loop) needs to be equipped with measurement sensors for inlet, outlet, and ambient temperature as well as irradiance, wind speed, and mass or volumetric flow rate to evaluate the heat balance. Assessing the individual measurement uncertainties and their impact on the combined uncertainty of the desired measurement quantity one obtains the significance of the testing results. The method has been applied to a set of EuroTrough collector tests performed at Plataforma Solar de Almería, Spain. Test results include the uncertainty range of the resulting modeling function and exemplify the effects of sensors and their specifications on the parameters leading to an uncertainty of ±1.7% points for the optical collector efficiency. The measurement uncertainties of direct normal irradiance and mass flow rate are identified as determining uncertainty contributions and indicate room for improvement. Extended multiple sensor deployment and improved calibration procedures are the key to further reducing measurement uncertainty and hence increasing testing significance.

T1538: Endoscopic Multiple Deployment of Metallic Stent Is Effective for the Chemotherapy to the Patients With Unresectable Hilar Biliary Strictures Due to Biliary Tract Carcinoma

Effective chemotherapeutic agents such as gemcitabine have been described in several reports on the treatment of biliary tract carcinoma. Since the patients with biliary tract carcinoma often accompany the hilar biliary tract carcinoma, the management of jaundice and cholangitis during chemotherapy is a key point to continue the effective chemotherapy. To avoid these complications in the course of chemotherapy, we performed endoscopic partial stent-in-stent deployment of multiple metallic stent (MS) on these patients. The aim of this study is to evaluate the efficacy of the chemotherapy to the patients receiving endoscopic multiple MS deployment due to unresectable hilar biliary strictures.

Distributed channel selection and randomized interrogation algorithms for large-scale and dense RFID systems

Radio frequency identification (RFID) is an emerging wireless communication technology which allows objects to be identified automatically. An RFID system consists of a set of readers and several objects, equipped with small and inexpensive computer chips, called tags. In a dense RFID system, where several readers are placed together to improve the read rate and correctness, readers and tags can frequently experience packet collision. High probability of collision impairs the benefit of multiple reader deployment and results in misreading. A common approach to avoid collision is to use a distinct frequency channel for interrogation for each reader. Various multi-channel anti-collision protocols have been proposed for RFID readers. However, due to their heuristic nature, most algorithms may not achieve optimal system performance. In this paper, we systematically design two optimization-based distributed channel selection and randomized interrogation algorithms for dense RFID systems. For this purpose, we develop elaborate models for the reader-to-tag and reader-to-reader collision problems. The first algorithm is fully distributed and is guaranteed to find a local optimum of a max-min fair resource allocation problem for RFID systems. The second algorithm is semi-distributed and achieves the global optimal system performance. Max-min fair optimality balances the performance and the processing load among readers. Simulation results show that our algorithms have significantly better performance than the previous heuristic algorithms.

Metrics correlation and analysis service (MCAS)

The complexity of Grid workflow activities and their associated software stacks inevitably involves multiple organizations, ownership, and deployment domains. In this setting, important and common tasks such as the correlation and display of metrics and debugging information (fundamental ingredients of troubleshooting) are challenged by the informational entropy inherent to independently maintained and operated software components. Because such an information pool is disorganized, it is a difficult environment for business intelligence analysis i.e. troubleshooting, incident investigation, and trend spotting. The mission of the MCAS project is to deliver a software solution to help with adaptation, retrieval, correlation, and display of workflow-driven data and of type-agnostic events, generated by loosely coupled or fully decoupled middleware.

In stent restenosis predictors after carotid artery stenting.

Purpose. The long-term efficacy of carotid artery stenting is debated. Predictors of stent restenosis are not fully investigated. Our aim was to assess the incidence of long term restenosis after CAS and to identify some predictors of restenosis. Methods. We retrospectively selected 189 treated patients and we obtained the survival Kaplan-Meier curves for overall survival, for freedom from stroke or death and from restenosis. To correlate clinical, radiological, and procedural variables to stent restenosis, an univariate analysis was performed while to determine independent predictors of restenosis, a multivariate analysis was applied. Results. At 1, 3, and 5 years, the cumulative overall survival rate was 98%, 94%, and 92% with a cumulative primary patency rate of 87%, 82.5%, and 82.5%. The percentage residual stenosis after CAS and multiple stents deployment were independent predictors of restenosis, while diabetes and tumors are suggestive but not significant predictors of restenosis. Conclusions. In our CAS experience, encouraging long-term results seem to derive from both neurological event free rate and restenosis incidence. Adequate recanalization of the treated vessel is important to limit the development of stent restenosis. Multiple stents deployment, and with less evidence, diabetes, or neoplasms has to be considered to facilitate restenosis.

Simulation of wake vortex effects for UAVs in close formation flight

AbstractThis paper addresses the development of multiple UAV deployment simulation models that include representative aerodynamic cross-coupling effects. Applications may include simulations of autonomous aerial refuelling and formation flying scenarios. A novel wake vortex model has been developed and successfully integrated within a Matlab/Simulink simulation environment. The wake vortex model is both sufficiently representative to support studies of aerodynamic interaction between multiple air vehicles, and straightforward enough to be used within real time or near real time air-to-air simulations. The model integration process is described, and computational results of a two-vehicle-formation flight are presented.

Endovascular repair for isolated iliac artery aneurysms: case report and review of the current literature

For a long time, open surgical repair has been considered the preferred management option for the exclusion of isolated iliac artery aneurysms.The development of transluminally placed endovascular stent grafts, which have been studied extensively for aneurysm exclusion in the abdominal and thoracic aorta, provided a less invasive approach for exclusion of iliac artery aneurysms as compared with surgical reconstruction or open surgical graft placement.Here we report a case of concomitant bilateral common and internal iliac artery aneurysms excluded successfully with multiple stent-grafting deployment with extension to the external iliac arteries and without coil embolization requirements.

Design and Development of an Augmented Reality Robotic System for Large Tumor Ablation

An augmented reality based robotic system is proposed for treatment of large liver tumor using multiple overlapping ablations technique. Radiofrequency ablation is a non-resection interventional procedure that minimizes invasiveness and reduces trauma. A single ablation is however limited by the ablation volume coverage. In treatment of tumor with diameter that could be 150mm or more, a single needle insertion will not create sufficient ablation coverage to destroy the entire tumor. As such, multiple insertions are required. The precision and consistency associated with robot assisted surgery coupled with direct augmented reality projection system can better facilitate such treatment. The projection system is equipped with manipulator mechanism and robotic needle insertion arm for multiple insertions and needle deployment. The prototype augmented reality surgical system was evaluated on its abilities in ablating large tumor. Virtual models of the rectangular robot for projector manipulation and robotic needle insertion device were also used to assess the effectiveness of the proposed AR design.

Cooperative Diversity with Multiple-Antenna Nodes in Fading Relay Channels

In this paper, we investigate the performance of a single-relay cooperative scenario where the source, relay and destination terminals are equipped with multiple transmit/receive antennas. We assume that conventional space-time block codes are employed in the underlying source-to-destination (SrarrD), source-to-relay (S rarr R) and relay-to-destination (R rarr D) links, and consider both decode-and-forward (DaF) and amplify - and-forward (AaF) relaying techniques. For the latter one, we consider two variants based on the availability of channel state information (CSI); namely, blind AaF and CSI-assisted AaF. Through the derivation of pairwise error probability, we quantify analytically the impact of multiple antenna deployment for each relaying technique under various scenarios which involve relay location and power control assumptions imposed on cooperating nodes. Our transmission model assumes that the source and destination terminals are equipped with MS transmit and N receive antennas, respectively, and the relay terminal is equipped with MR receive and MT transmit antennas. For a scenario where R rarr D and S rarr D links are balanced and S rarr R link experiences sufficiently large SNR, our performance analysis demonstrates that the maximum achievable diversity order is MT min(MS, N)+MSN for blind AaF scheme and N(MT+MS) for both CSI-assisted AaF and DaF schemes. For another scenario where R rarr D link has a sufficiently large SNR and S rarr R and S rarr D links are balanced, CSI-assisted AaF, blind AaF and DaF schemes achieve diversity orders of MS(N + MR), MS(N + MT), and MSN, respectively. Other scenarios involving the availability of non-fading R rarr D link and poor inter-user channel quality are further investigated. An extensive Monte Carlo simulation study is also presented to corroborate the analytical results and to provide detailed performance comparisons among the three relaying techniques under consideration.