Setup Phase Research Articles

Energy Efficient Cluster-Based Routing Protocol in Wireless Sensor Network using Flower Pollination Algorithm

Main ambition of wireless sensor networks (WSN) is to exploit network lifetime and stability periods. Flower Pollination Algorithm (FPA) is uses to elect the cluster head (CH) in set up phase of WSN such that the intra cluster average distance between the member nodes and their respective CHs is minimized and the sum of ratio of residual energy of alive nodes in cluster or energy level of CH is also minimized via maximized. In the research, a Flower Pollination Algorithm based Energy Efficient Routing Protocol (EERPFPA) has been proposed to apply FPA the problem of electing the CH in the cluster set-up phase based on minimizing the intra cluster average distance between the member nodes and their CHs and minimizing the sum of ratio of remaining power/energy of active sensor nodes in cluster to energy/power intensity of CH. It efficiently maximizes the network life time and improves the stability period. In this paper, the simulation results are showed by using MATLAB. The results showed that the proposed algorithm is more energy efficient and more reliable in clustering process as compared to WSN with Harmony search algorithm (HSA) for heterogeneous networks.

Secure computation without computers

The design of secure protocols which can be used without the aid of a computer and without cryptographic knowledge is an interesting and challenging research task. Indeed, protocols enjoying these features could be useful in a variety of settings where computers cannot be used or where people feel uncomfortable to interact with or trust a computer. In this paper we make a step in such a direction: we propose a novel method for performing secure two-party computations that, apart from the setup phase, requires neither a computing machinery nor cryptographic knowledge. By merging together in a suitable way two beautiful ideas of the 80's and the 90's, Yao's garbled circuit construction and Naor and Shamir's visual cryptography, respectively, we enable Alice and Bob to securely evaluate a function f(⋅,⋅) of their inputs, x and y, through a pure physical process. Indeed, once Alice has prepared a set of properly constructed transparencies (for this activity a computer is useful), Bob computes the function value f(x,y) by applying a sequence of simple steps which require the use of a pair of scissors, superposing transparencies, and the human visual system. Our construction builds on Kolesnikov's gate evaluation secret sharing schemes.

Continuous gas transfer monitoring during extracorporeal membrane oxygenation

Abstract Extracorporeal membrane oxygenation therapy can prevent hypoxia, and the related inherent danger of death, if mechanical ventilation does not maintain sufficient physiological gas exchange. This form of therapy provides supplemental extracorporeal blood oxygenation and decarboxylation. The most important values to be monitored for the supervision of extracorporeal gas exchange are blood gas measurements, which are normally obtained only intermittently. Continuous measurement during this therapy is rarely implemented because the devices used are costly, and the amount of supervision and maintenance required is complex and expensive (even on the relatively short term of several hours). We present an alternative approach to supervise extracorporeal gas exchange that avoids the use of blood gas analyzers. This is achieved using venous oxygen saturation and additional sensors within the gas phase of the extracorporeal setup. Finally, carbon dioxide gas transfer is measured directly and oxygen gas transfer is estimated using an extended Kalman filter based on an evaluated gray-box model. The proposed method is characterized in silico and evaluated using in vivo data (accuracy of oxygen gas transfer estimation 9.1 ± 49 mL/min). Results suggest that monitoring of gas transfer with adequate performance is possible and that clinical application using this measurement value in closed-loop control is also feasible.

Avulsion cycles and their stratigraphic signature on an experimental backwater‐controlled delta

AbstractRiver deltas grow in large part through repeated cycles of lobe construction and channel avulsion. Understanding avulsion cycles is important for coastal restoration and ecology, land management, and flood hazard mitigation. Emerging theories suggest that river avulsions on lowland deltas are controlled by backwater hydrodynamics; however, our knowledge of backwater‐controlled avulsion cycles is limited. Here we present results from an experimental delta that evolved under persistent backwater hydrodynamics achieved through variable flood discharges, shallow bed slopes, and subcritical flows. The experimental avulsion cycles consisted of an initial phase of avulsion setup, an avulsion trigger, selection of a new flow path, and abandonment of the parent channel. Avulsions were triggered during the largest floods (78% of avulsions) after the channel was filled by a fraction (0.3 ± 0.13) of its characteristic flow depth at the avulsion site, which occurred in the upstream part of the backwater zone. The new flow path following avulsion was consistently one of the shortest paths to the shoreline, and channel abandonment occurred through temporal decline in water flow and sediment delivery to the parent channel. Experimental synthetic stratigraphy indicates that bed thicknesses were maximum at the avulsion sites, consistent with our morphologic measurements of avulsion setup and the idea that there is a record of avulsion locations and thresholds in sedimentary rocks. Finally, we discuss the implications of our findings within the context of sustainable management of deltas, their stratigraphic record, and predicting avulsions on deltas.

OVERCOMING CHALLENGES OF SETTING-UP A LARGE AND COMPLEX PRE-HOSPITAL TRIAL: AIRWAYS-2

BackgroundAIRWAYS-2 is an NIHR-funded study to determine the best initial approach to advanced airway management during out of hospital cardiac arrest (OHCA). The trial will enrol more than 9,000 patients and 1,500 paramedics. To achieve this, collaboration between four Ambulance Trusts and every hospital served by these was required. Patients receive the trial intervention pre-hospital, and the primary outcome and other data are collected in-hospital. We describe the set-up process for this large, complex, pre-hospital trial.MethodsPre-hospital research presents unique challenges. Obtaining approvals and set-up can be complex, time consuming and expensive. A strategy to engage with all stakeholders was developed, ensuring that they were well informed during the planning and set-up phases. Specifically, this included: establishing R&D and Clinical Research Network contacts; involving critical care leads; consultation with ambulance trusts; utilisation of network support; implementation of a wide-reaching communications plan. All hospitals were contacted to identify local collaborators prior to SSI submission, and were provided with FAQs and study information. The approval process was streamlined. The SSI was generic and did not require input from local teams. A one page statement of responsibilities replaced review of contracts for sites. Comprehensive review by REC & CAG meant that full consideration was given to the ethical challenges during planning and set-up phases.ResultsTrust permission was obtained from all acute hospitals (95 in total), served by participating ambulance trusts. All set-up milestones were achieved and the first patient was enrolled on time.ConclusionsAmbulance services are increasingly research active. Incidents attended can be life-threatening emergencies but good quality pre-hospital trials are possible. Early and comprehensive engagement assists with sites' participation and enables successful set-up of collaborative trials.

Improving Energy-Efficiency of WSNs through LEFCA

Wireless sensor networks (WSNs) have become an important part of our lives as they can be used in vast application areas from disaster relief to health care. As a consequence, the life span and the energy consumption of a WSN have become a challenging research area. According to the existing studies, instead of using direct transmission or multihop routing, clustering can significantly reduce the energy consumption of sensor nodes and can prolong the lifetime of a WSN. In this paper, we propose a low energy fixed clustering algorithm (LEFCA) for WSNs. With LEFCA, the clusters are constructed during the set-up phase. A sensor node which becomes a member of a cluster stays in the same cluster throughout the life span of the network. LEFCA not only improves the lifetime of the network but also decreases the energy dissipation significantly.

Genetic Algorithm based Energy Efficient Data Gathering in Wireless Sensor Networks

In this paper genetic algorithm based energy efficient data gathering approach is proposed to maximize the network lifetime in terms of rounds. The proposed approach has two phases, namely a setup phase and steady state phase. In the setup phase, the cluster formation is done based on the query sent by the base station in a dynamic fashion. The nodes, which satisfy the query are only allowed to participate in the clustering process others go to the sleep mode immediately. In which relay nodes are used as routing element, it collects the aggregated information from the cluster head and transmits to the base station via other relay node in a multihop fashion. It balances the network load among the relay nodes. It also reduces the packet loss because of data traffic. From the simulation results, we show that the proposed approach outperforms than the existing protocol in terms of increased network lifetime and decreased energy consumption.

An Energy Efficient Routing Protocol using ABC to Increase Survivability of WSN

days proficient design and realization of wireless sensor networks has turn into a hot area of research in recent time, due to the immense potential of sensor networks to enable applications that bond the substantial world to the virtual world. Wireless sensor network (WSN) is being used in surveillance, medical monitoring etc. Sensors nodes are typically built of few sensors and a mote unit. A Sensor is a piece of equipment which wits the information and passes it on to mote. Sensors are usually used to compute the changes in substantial environmental parameters like warmth, strain, moisture, noise, tremor and changes in the fitness parameter of person e.g. blood pressure and the rate at which the heart beats. In this research a technique named ABC Based Energy Efficient Protocol (ABCEEP) is projected to apply Artificial Bee Colony (ABC) to the problem of electing the cluster heads in the cluster set-up phase based on minimizing the cluster's consistency/break up/compactness (intra remoteness) and maximizing the cluster separation (inter remoteness) to proficiently increase the network life span and to get better stability period.

Parallel Multiscale Linear Solver for Highly Detailed Reservoir Models

Summary To realize the potential of the latest high-performance computing (HPC) architectures for reservoir simulation, scalable linear solvers are necessary. We describe a parallel algebraic multiscale solver (AMS) for the pressure equation of heterogeneous reservoir models. AMS is a two-level algorithm that uses domain decomposition with a localization assumption. In AMS, basis functions, which are local (subdomain) solutions computed during the setup phase, are used to construct the coarse-scale system and grid-transfer operators between the fine and coarse levels. The solution phase is composed of two stages: global and local. The global stage involves solving the coarse-scale system and interpolating the solution to the fine grid. The local stage involves application of a smoother on the fine-scale approximation. The design and implementation of a scalable AMS on multicore and many-core architectures, including the decomposition, memory allocation, data flow, and compute kernels, are described in detail. These adaptations are necessary to obtain good scalability on state-of-the-art HPC systems. The specific methods and parameters, such as the coarsening ratio (Cr), basis-function solver, and relaxation scheme, have significant effects on the asymptotic convergence rate and parallel computational efficiency. The balance between convergence rate and parallel efficiency as a function of Cr and the local stage parameters is analyzed in detail. The performance of AMS is demonstrated using heterogeneous 3D reservoir models, including geostatistically generated fields and models derived from SPE10 (Christie and Blunt 2001). The problems range in size from several million to 128 million cells. AMS shows excellent behavior for handling fixed-size problems as a function of the number of cores (so-called strong scaling). Specifically, for a 128-million-cell problem, a ninefold speedup is obtained on a single-node 12-core shared-memory architecture (dual-socket multicore Intel Xeon E5-2620-v2), and more than 12-fold on a single-node 20-core shared-memory architecture (dual-socket multicore Intel Xeon E5-2690-v2). These are encouraging results given the limited memory bandwidth that cores can share within a single node, which tends to be the major bottleneck for truly scalable solvers. We also compare the robustness and performance of our method with the parallel system algebraic mutligrid (SAMG) solver (Stüben 2012) from Fraunhofer SCAI.

Constructions of dynamic and non-dynamic threshold public-key encryption schemes with decryption consistency

Dynamic threshold public-key encryption, proposed by Delerablée and Pointcheval (CRYPTO 2008), is an extension of ordinary threshold encryption which enables decryption servers to join the system even after the setup phase, and to choose the authorized set and the threshold of decryption dynamically. Delerablée and Pointcheval proposed the first dynamic threshold public-key encryption scheme, which they proved secure under a non-standard q-type assumption. However, decryption consistency, which is an important security property that guarantees uniqueness of decryption, even when a sender and decryption servers behave maliciously, is only shown to hold in the random oracle model. In this paper, we propose three threshold public-key encryption schemes. The first and second schemes are both dynamic schemes. The former achieves a relatively weaker variant of decryption consistency, while the latter achieves a strong variant thereof. The former is a generic construction from public-key encryption with non-interactive opening (PKENO), while the latter is a specific construction from a standard number-theoretic assumption. These are the first constructions of dynamic public-key encryption, which achieve decryption consistency without relying on the random oracle model. Furthermore, both schemes can be realized based on standard assumptions. The third construction is a generic construction from PKENO achieving the strong variant of decryption consistency. This construction affirmatively answers the question indirectly posed by Galindo et al. (AFRICACRYPT 2010) of whether a generic construction achieving strong decryption consistency is possible.

HTTPDissect: Detailed Performance Analysis of HTTP Web Browsing Traffic in TDMA Mesh Networks

TDMA based wireless mesh networks have gained prominence as some of the recent standards such as WiMAX and 802.11s have proposed the use of TDMA based MAC protocol for mesh networks. Even though HTTP web browsing traffic constitutes a significant percentage of Internet traffic, but as of yet there have been no attempts to study the performance of HTTP based web browsing traffic in TDMA mesh networks. HTTP web browsing traffic has different characteristics compared with other types of traffic. In particular, as HTTP traffic consists of large number of small sized file transfers (median file size is 10 KB), it can impose high scheduling overhead. As we highlight, HTTP traffic requires that RTT (round trip time) be small and also it requires that large sized flows be allocated higher share of bandwidth. Given these characteristics of HTTP traffic, it is not clear what protocol design for TDMA mesh networks performs best. In this work, we have studied the performance comparison of four different TDMA MAC protocols for HTTP web browsing traffic. Two of these protocols follow distributed scheduling, one centralized and the other naive static fixed schedule approach. We compare the TDMA MAC protocols for various aspects such as optimum values of different TDMA MAC parameters, design of TDMA scheduling algorithm, performance under varying load, in presence of wireless loss, etc. Our study highlights a crucial aspect that the two distributed protocols specified by the recent WiMAX and 802.11s standards, are incapable of handling wireless packet loss and perform poorly in presence of large HTTP file downloads. As against this, the centralized protocol performs well for the different experiment cases that we have considered. However, our analysis reveals that the performance of the centralized protocol can be further improved if we eliminate the flow set-up phase and minimize the delay in propagating the TDMA schedule. Likewise, we carry out required modifications to the centralized protocol and observe that the performance of the modified protocol, which we term as the sf-centralized (set-up free centralized) protocol, improves by as much as 19 percent under moderate load and 47 percent under high load.

An Improved Load Balanced Connection Aware Clustering Hierarchy Protocol for Military Application in Mobile Ad Hoc Network

Mobile Ad-hoc Networks (MANETs) are expected to play an important role in military networks by providing infrastructure less communication. However, maintaining secure and instant information sharing is a difficult task especially for highly dynamic military MANETs. Different solution proposed for scaling own the large size of military ad hoc network, one of the most intrinsic approaches is clustering techniques which evolved an important role in military mobile ad hoc networks. Clustering can be used for load balancing to extend the lifetime of ad hoc network by reducing energy consumption and increase network scalability. And the cluster one node works as a cluster head and coordinates all the activities such as routing. In this study, an Improved Load Balanced Connection Aware (ILBCA) clustering hierarchy protocol is presented for MANET that leads to cluster formation in military application. The protocol launches two consecutive phases called setup and steady-state. In setup phase, cluster heads and relay nodes as well as the path between member node from cluster and cluster head are determined. In steady-state phase, network data is collected from member nodes and transmitted to cluster head according to the topology which is determined in the same round. Simulated tests indicate that the ILBCA clustering hierarchy protocol can build more balanceable clustering structure, enhance the network life cycle and energy efficiency.

Small roll angle measurement using lateral shearing cyclic path polarization interferometry.

We present a technique for the measurement of roll angular displacement of a rotary stage using a lateral shearing cyclic path optical configuration (CPOC) setup and polarization phase shifting interferometry (PPSI). The CPOC setup, aligned on the rotary stage, laterally shears the input plane polarized spherical beam into a pair of orthogonally polarized beams, which when brought to the same state of polarization by a polarizer produce interference fringes similar to Young's fringes. Rotation of the CPOC setup in its plane introduces a phase change between the orthogonally polarized lateral sheared beams due to the change in angle of incidence of the input beam. The change in the phase results in spatial displacement of the interference fringes. Using PPSI, the phase, or the optical path difference change between the laterally sheared beams that is related to the rotation angle of the CPOC setup, is measured.

Incorporating Critical Thinking into an Engineering Undergraduate Learning Environment

Critical thinking extends to all aspects of professional engineering, especially in technical development, and, since the introduction of the ABET 2000 criteria, there has been an increased emphasis in engineering education on the development of critical thinking skills. What is hoped for is that the students obtain critical thinking skills to complement their abundant logical thinking skills. Critical thinking is a developmental skill that cannot be taught simply by traditional methods, i.e., step-by-step instruction followed by repetitive skills, as used for logical thinking skills. The research and development reported here is concerned with outlining how students first can be alerted to what critical thinking is, and how critical thinking can be nurtured through practical experience with appropriate guidance and reinforcement. The module ‘Introduction to Fluid Mechanics’ has been selected to demonstrate how formal critical thinking components may be introduced with the development of principles of logic and an obligatory problem solving procedure. A method of assessment during various phases of critical thinking, i.e., initial design or set-up, testing of method or prototype, and evaluation of the results, of open-ended assignments in engineering for each year of the undergraduate course has been developed.

A new unequal clustering protocol with local re-clustering mechanism for wireless sensor networks

A new unequal clustering protocol with local re-clustering mechanism is proposed to mitigate the 'hot spot' problem and thereby prolong the network lifetime of a wireless sensor network WSN. In the setup phase, the network is partitioned into several unequal-size layers based on the minimum hop count of each node to the base station BS. Then each layer is further partitioned into several layer-dependent-size clusters by a weight-based cluster head CH competition, where candidate nodes participating in CH election are selected by the BS with a new exploration approach. In addition, we propose a local re-clustering mechanism to further mitigate the uneven energy load during the data transmission phase, that is, different layers reselect their CHs at different frequencies according to their relative distances to the BS. Furthermore, for local re-clustering, a simplified CH rotation approach is proposed to lessen the communication and computation overhead. The simulation results demonstrate that our proposed protocol is effective in prolonging the network lifetime and in balancing the energy consumption.

The self-configuration of nodes using RSSI in a dense wireless sensor network

Wireless sensor networks (WSNs) may be made of a large amount of small devices that are able to sense changes in the environment, and communicate these changes throughout the network. An example of a similar network is a photo voltaic (PV) power plant, where there is a sensor connected to each solar panel. The task of each sensor is to sense the output of the panel which is then sent to a central node for processing. As the network grows, it becomes impractical and even impossible to configure all these nodes manually. And so, the use of self-organization and auto-configuration algorithms becomes essential. In this paper, three algorithms are proposed that allow nodes in the network to automatically identify their closest neighbors, relative location in the network, and select which frequency channel to operate in. This is done using the value of the Received Signal Strength Indicator (RSSI) of the messages sent and received during the setup phase. The performance of these algorithms is tested by means of both simulations and testbed experiments. Results show that the error in the performance of the algorithms decreases as we increase the number of RSSI values used for decision making. Additionally, the number of nodes in the network affects the setup error. However, the value of the error is still acceptable even with a high number of nodes.

Lean initiative practice for supplier developments in Philippines

Purpose– The purpose of the paper is to demonstrate how Toyota deploys Lean Manufacturing and Toyota Production System (TPS) for their automotive parts’ suppliers in Philippines based on the case study and the literature review.Design/methodology/approach– The methods to better understand how Toyota donates Lean Manufacturing to develop their suppliers include to review the general Lean thinking process and tools and study in depth the selected Lean manufacturing tools that are directly related with Toyota supplier development and to show the actual implementations base in the case of the supplier of Toyota in Philippines.Findings– The result of the case study shows how Toyota donates their Lean manufacturing (TPS) methods to the suppliers. There are several procedures and various tools for the Lean process. But one procedure within the process and only some of the Lean tools are suitable for supplier development. The case shows that all improvements (Kaizen) during the Lean implementation should be directly intertwined onsite (Genba) and just a small amount of the Lean tools is needed in real-world situations. In other words, the consultation of the Lean implementation might not require the full package of the Lean implementations. More importantly, the consultations of the Lean implementation without deeply understanding the onsite are useless.Research limitations/implications– The project for the Lean deployment for supplier implementation is targeted to understand the full procedure from the start to the end, but the case in this paper is only covering the setup phase. As the suppliers of Toyota, there are additional parts to be implemented (i.e. shipping management), but it is not covered in this paper.Originality/value– There are some researches about Lean implementation framework, and only few cases deal with the actual Lean implementations. But the case about the Lean implementation of supplier development initiation which aligned with the Toyota Company is unique.

Reducing Communication Costs for Sparse Matrix Multiplication within Algebraic Multigrid

We consider the sequence of sparse matrix-matrix multiplications performed during the setup phase of algebraic multigrid. In particular, we show that the most commonly used parallel algorithm is often not the most communication-efficient one for all of the matrix-matrix multiplications involved. By using an alternative algorithm, we show that the communication costs are reduced (in theory and practice), and we demonstrate the performance benefit for both model (structured) and more realistic unstructured problems on large-scale distributed-memory parallel systems. Our theoretical analysis shows that we can reduce communication by a factor of up to 5.4 for a model problem, and we observe in our empirical evaluation communication reductions of factors up to 4.7 for structured problems and 3.7 for unstructured problems. These reductions in communication translate to run-time speedups of factors up to 2.8 and 2.5, respectively.

교사의 수업반성이 수학 수업에 주는 영향 - 수학적 과제의 인지적 수준을 중심으로 -

본 연구의 목적은 수학적 과제의 인지적 수준에 대한 교사의 수업반성이 수학 수업에 어떠한 영향을 주는지 분석하여 초등 교사의 수학 수업에 시사점을 제공하는 것이다. 이를 위해 수학 수업에서 과제 설정과 과제 실행단계 동안, 수학적 과제의 인지적 수준의 변화와 변화에 영향을 준 교실 요인을 분석하고, 이에 대한 수업반성을 거쳐 실시한 수학 수업에서 과제 설정과 과제 실행 단계동안, 수학적 과제의 인지적 수준의 변화 양상 및 변화에 영향을 준 교실 요인을 분석하였다. 그 결과, 수학적 과제의 인지적 수준이 쇠퇴했던 수학 수업이 수업반성을 통해 수학적 과제의 인지적 수준이 높게 유지하는 수학 수업으로 변화하였다. The purpose of this study is to offer the implication for elementary school mathematics teaching by analyzing teachers' reflection on the cognitive demands of mathematical tasks they give in class. During the setup phase and the implementation phase in math class, the researchers analyzed the change of cognitive demands on mathematical tasks and the factors which had influence on such changes. After teachers' reflection on teaching, the researchers analyzed the change of cognitive demands on mathematical tasks and the factors which had influence on such changes in math classes. As a result, before teachers' reflection on the cognitive demands of mathematical tasks, the higher-level demands of mathematical tasks had a tendency to decline. However, after teachers' reflection on the cognitive demands of mathematical tasks, higher-level demands of mathematical tasks were maintained.

Aggregation for adaptive and energy-efficient MAC in wireless sensor networks

Time Division Multiple Access (TDMA) protocols are considered an energy-efficient solution to prolong wireless sensor network lifetime. However, their drawbacks such as the complexity of slot assignment and schedule maintenance, clock synchronization and low channel utilization during low traffic conditions are to be overcome in a good and efficient way. In this paper we present On-demand Convergecast Sensor MACS (OCSMACS), a centralized and adaptive multihop scheduling-based TDMA protocol for Wireless Sensor Networks. OCSMACS achieves high energy efficiency by adopting a novel requests aggregation mechanism for adaptive slot assignments such that all requests generated by active nodes are aggregated in a very few small size packets. In addition, knowledge of data correlation is integrated in the design of underlying multihop scheduling schemes to improve energy efficiency and extend network lifetime. Furthermore, OCSMACS adopts an energy-efficient protocol called PROGRESSIVE for the topology discovery and setup phases. The performance of OCSMACS is compared against existing protocols based on simulations using ns-2 and the results show that OCSMACS outperforms these protocols in terms of energy efficiency and network lifetime. Also, the integration of correlation knowledge in the scheduling process improves performance and extends network lifetime.