Number Of Alternative Routes Research Articles

Routing and spectrum assignment: A metaheuristic for hybrid ordering selection in elastic optical networks

Routing and spectrum assignment (RSA) problem, in elastic optical networks, searches for a route and a sufficient spectrum range to fit each network request. Solving these two problems simultaneously is a complex work. Therefore, they are usually assumed separately by either solving the routing firstly and then the spectrum assignment for this selected route or prioritizing some spectral ranges and then searching for a route that meets such spectrum requirements. The former strategy prioritizes the reduction on the network occupation by using short routes first, while the latter emphasizes load distribution and a more efficient spectrum organization. According to some aspects, such as network topology, number of alternative routes, traffic intensity and number of available slots, emphasizing either set of benefits results in superior advantage. This paper presents a comprehensive study about RSA ordering strategies and proposes a hybrid resource-allocation ordering approach to decide between either strategy. RSA ordering means performing spectrum assignment in function of routing or performing routing in function of some candidate spectrum ranges pre-computed by some SA algorithm criteria An efficient metaheuristic based on genetic algorithm is proposed to implement this strategy, named hybrid routing and spectrum assignment (HRSA). The proposed algorithm returns the most suitable RSA ordering choice for each source–destination pair, which provides near-lowest path-request blocking probability. Simulation results show that the RSA ordering returned by the proposed HRSA reduces the path-request blocking probability up to 35% in comparison to the classical RSA orderings.

ANALISIS POTENSI KAWASAN PESISIR PANTAI KOTA PADANG SEBAGAI WISATA OLAHRAGA MARATON BERSKALA INTERNASIONAL

Lately, the coastal city of Padang has been improving and being promoted. One of the efforts that can advance tourism is through the introduction and development of national and international sports tourism such as marathons. Marathon is one of the popular sports, such as the New York City Marathon, Parias Marathon, Asia Tokyo Marathon, Tour De France, Bali sailboat competition. This research includes mapping the potential of international scale marathon tourism, how to analyze the potential of sports tourism and the obstacles in the development of sports tourism in the city of Padang. In this study, researchers observed coastal locations that have the potential to develop marathon tourism tourism by looking at the level of tourist development, information on potential locations obtained from informants / informants, these locations have been tested and used for marathon tourism.
 The internal potential of this marathon sports tour is "high potential" to be held with the quality of marathon tourist attractions and tracking conditions are very good. External potentials include accessibility; object support facilities; complementary facilities, and object development support, this is "high potential" for holding International-scale Marathon Tourism activities. Marathon tourism can be held with a variety of competition criteria by participating in the role of the surrounding community; provide packages offering attractive activities of all ages, clear supporting facilities information; widely introduce to the public a series of marathon tourism activities.
 The 10K track with diverse contours offers sports and tourism experiences; several narrow road spots so as not to be filled by vehicles or the activities of the local community; the track route is a public area, the number of alternative routes can be used for road transfers; the field committee is able to coordinate public vehicle traffic during the event. Alternative roads and parking areas to be managed by involving local communities so that activities run smoothly. The government helps manage community business activities; avoid illegal payments so as to provide comfort for tourists; parking area prepared to anticipate the emergence of wild parking; education and sanctions for people who do not maintain cleanliness and sanction if there is extortion. Promotion of tourism and sports activities to be further intensified through all media publications; provide opportunities for local EOs and professional EOs to collaborate in the learning process; promotion and clear and mutually beneficial cooperation relationships.

Ekspertni pristup poboljšanju sigurnosti u zonama radova na cesti

SUMMARY: An ever-increasing volume of traffic on Croatian roads increases the volume of maintenance work. Road works negatively impact traffic mobility and road user safety, and also safety of the maintenance workers. Improving traffic mobility and safety is the key issue that all interested parties (planning and managing road works and those executing them) should address. Mitigation of negative effects is possible via certain expert system measures. Presented in the paper are the options provided by expert systems implemented in the road work zones as factors for improving road maintenance and safe traffic flow, as well as road workers safety. Introducing relevant data into the data base, an expert system is created providing the driver approaching a road work zone with a number of alternative routes. Also shown is a driving diagram for road work zones with special focus on slowing down speed upon entering the road work zone. The results show that the implementation of expert systems based on relevant data would significantly facilitate traffic management in road work zones and improve the safety of traffic and road workers, as well as the workers' efficacy.

Calibration of C-Logit-Based SUE Route Choice Model Using Mobile Phone Data

Theoretically speaking, the data of a stated preference survey could be suggested for the calibration of a stochastic route choice model. However, it is unrealistic to implement the questionnaire survey for such a large number of alternative routes. Engineers generally determine the parameter empirically. This experienced choice of perception parameter may cause higher errors in the route flows. In our calibration model of the perception parameter, the data of the cellular network is set as the input. This model consists of two levels. The upper level is to minimize the gap squares of the route choice ratio between the C-logit model and the cellular network data. The stochastic user equilibrium (SUE) in terms of the C-logit model is used as the lower level. The simulated annealing (SA) algorithm is used to solve the model, where the route-based gradient projection (GP) algorithm is used to solve the inner SUE. A case study is used to validate the convergence of the model calibration. A real-world road network is used to demonstrate the objective advantage of an equilibrium constraint over a nonequilibrium constraint and explain the feasibility of the candidate routes assumption.

An efficient load balancing method for ad hoc networks

SummaryRouting is the most basic and essential operation of any ad hoc network. A mobile ad hoc network presents many challenges, because of the severe resource limitations such as dynamic and varying topology, lack of centralized control, insecure medium, and limited battery power, among others. Therefore, optimization and conservation is the key to success of any ad hoc network operation. In this paper, we propose and define 2 new metrics for ad hoc networks: bandwidth utilization ratio and load index. These metrics can be used as an indicator to measure and monitor the network usability and to improve its efficiency by efficient load distribution. They can be used to predict the additional load that can be accommodated in the network, without causing any congestion or overflows. We also propose a new load balancing routing scheme for ad hoc networks, called efficient load balancing method. This method tries to offset the load on different paths using load index as a metric. Load index is defined as a measure of a node's degree of involvement in the message routing process, which is indicative of its load. To make this algorithm efficient, we limit our routes to a few efficient ones only. This number of alternate routes used, out of the pool of all available routes, is defined as degree of distribution. Simulation results adequately prove the efficiency of proposed method, vis‐à‐vis 2 other load balancing approaches, and these are verified statistically at 99% confidence interval. A p × q factorial design is used to verify that simulation results are the actual measurements and not due to some unknown errors.

Machine Cell Formation with Alternative Routings based on Genetic Algorithm

In automated batch type production systems, machine-part cell formation problems (CFP) have long drawn attention of researchers. The objective of CFP in cellular manufacturing system (CMS) is to identity machine cells and part families in order to minimize the intercellular movements of parts as well as maximize the utilization of machines. Optimum cell formation results reduction in total production times, in-process inventories, material handling cost, labor cost/times, paper works, number of machine set-ups, set-up times. It also simplifies process plans, management and improves product quality, productivity, utilization of resources. Since the modern manufacturing machines are generally multifunctional, so the processing of parts can be performed by number of alternative routes. The objectives of this study are to determine the optimal machine cells with optimal processing route and balanced machine cells (minimum cell load variation). Here a genetic algorithm heuristic approach is presented for six benchmark problems with multiple process routes, sequence of processes and parts volume. Computational outcome show that the proposed heuristic gives better result comparatively with the well-known existing methods in terms of total intercellular movements.

The Equivalent Thévenin-Network Representation of a Pulse-Excited Power-Ground Structure

The $N$ -port equivalent Thevenin representation of a power-ground structure is constructed using the Lorentz reciprocity theorem of the time-convolution type. It is shown that the introduced multiport Kirchhoff-circuit representation offers a number of alternative routes to determining the pulsed electromagnetic radiated emissions of a power-ground structure from its response to an electromagnetic disturbance in the receiving situation. Moreover, the result may serve as an important check on the validity of numerical solutions to related electromagnetic radiation problems. An illustrative example that validates the equivalent-circuit representation is given.

Robust routing based on urban traffic congestion patterns

Abstract: In your daily journeys, you are driving from a departure location to another destination location situated in the road network. There are a number of alternative routes that you could use. For each section of the network, we know the travel time required under normal traffic conditions to move from one endpoint to the other. What we do not know is the occurrence of incidents that slow down traffic and cause traffic congestion and therefore delays. This work considers the development of simple traffic model based on the semi-microscopic traffic assumption. The simulator based on the proposed model makes it possible to estimate the travel time on a road link. From variables, provided by simulator we can derive travel time index and therefore to characterize the traffic state of the urban transportation network. Another objective of this paper is to determine a robust itinerary in an urban transport network, taking into account the dynamic aspects of traffic congestion.

A Networks Approach to Modeling Enzymatic Reactions.

Modeling enzymatic reactions is a demanding task due to the complexity of the system, the many degrees of freedom involved and the complex, chemical, and conformational transitions associated with the reaction. Consequently, enzymatic reactions are not determined by precisely one reaction pathway. Hence, it is beneficial to obtain a comprehensive picture of possible reaction paths and competing mechanisms. By combining individually generated intermediate states and chemical transition steps a network of such pathways can be constructed. Transition networks are a discretized representation of a potential energy landscape consisting of a multitude of reaction pathways connecting the end states of the reaction. The graph structure of the network allows an easy identification of the energetically most favorable pathways as well as a number of alternative routes.

Indicadores do desenho urbano e sua relação com a propensão a caminhada

A viagem a pé envolve certas condições frequentemente denominadas como caminhabilidade, observando-se vários estudos que buscam estabelecer, não só os fatores que interferem nela como os indicadores usados para medi-la. Um destaque vem sendo dado ao ambiente construído e, em particular, ao desenho urbano, que configura a rede de caminhos. A configuração desta rede, sua densidade e conectividade afetam os tempos, a continuidade dos deslocamentos a pé, bem como o número de itinerários alternativos. A partir da revisão da bibliografia e dos índices disponíveis na Teoria dos Grafos, estabelecem-se os indicadores mais adequados para representar o desenho urbano e para investigar a influência da configuração da rede de caminhos na propensão a caminhada. Conceitualmente, indicadores derivados dos ciclos tendem a melhor explicar a conectividade. Sugere-se ainda, de forma exploratória, uma escala, baseada em indicadores de fácil obtenção, que expresse o potencial de uma dada área favorecer as viagens a pé, de acordo com tal configuração. Essa escala pode contribuir para a escolha de áreas para a implantação de Polos Geradores de Viagens orientados aos pedestres.

Passing on the Hot Potato: Lessons from a Policy Brief Experiment

Research has potential to improve the lives of the world's vulnerable people – if it is appropriately referred to in decision‐making processes. While there is a significant industry of activity each year to communicate research findings, little systematic research has tested or compared the effectiveness of such efforts. One popular research communication tool is the policy brief. In this article we draw on findings from a recent study on how a policy brief works; concluding that a policy brief does not have a linear effect on its readers. Instead, a reader can take a number of alternative routes from belief to action, some of which could subvert the intended outcome of the policy brief in question. We reflect also on the question of what makes for an effective policy brief; concluding that policy briefs that give personality and form to the researcher behind the written word may invoke a deeper relationship between the reader and the author, and affect a greater inclination in the reader to share the message with someone else – that is, they pass the hot potato. 1 The study itself was a first of its kind and contributes to our understanding about the effectiveness of research communication, as well as how to evaluate research communication effectiveness.

Challenges surrounding widening participation and fair access to initial teacher education: can it be achieved?

Access to initial teacher education (ITE) across the United Kingdom continues to be significantly determined by selective entry requirements, based on prior academic qualifications. While a number of alternative routes to teacher education exist, several barriers to participation in higher education, including teacher education, still exist. Within this paper, the concept of fair access and its relevance for teacher education is examined, as well as the extent to which government initiatives, designed to widen participation, are exemplified in ITE selection processes. Quantitative data for the study were obtained from an analysis of application data from those applying for teaching, while qualitative data using semi‐structured interviews with all ITE university tutors sought information about the effectiveness of current recruitment and selection arrangements, at the University of Ulster in Northern Ireland, for postgraduate ITE programmes. Collectively, the data highlighted the need for more innovative, inclusive selection process if a more representative teaching workforce is to be achieved, capable of meeting the needs of increasingly diverse learners.

Development of a Methodology for Assessing Inherent Occupational Health Hazards

In the preliminary stages of chemical plant design, selecting the chemical process route is one of the main design decisions. Previously, the most important factor in selecting the best chemical process route was economics. Now safety, environmental and occupational health issues have become important considerations. Health risks to workers could be reduced by better selection of the chemical process route during the initial stages of process design. The chemical process route may be defined as the raw material(s) and the sequence of reactions that converts them to the desired product(s). In order to choose the ‘healthiest’ one from a number of alternative routes, the potential health hazards must be quantified. Ranking of alternative chemical process routes based on the severity of potential health effects to the workers exposed could provide an assessment method for avoiding potential harm to humans. The Process Route Healthiness Index (PRHI) has been developed to quantify the health hazards that might arise from chemical processes; the higher the index, the higher the hazards. The PRHI is influenced by the health impacts due to potential chemical releases and the concentration of airborne chemicals inhaled by workers. The index has been applied to six alternative routes to methyl methacrylate (MMA). The resulting ranking is compared to those obtained from an Inherent Safety Index, an Environmental Hazard Index and production cost estimates for the same chemical process routes.

Forming part families by using genetic algorithm and designing machine cells under demand changes

This study develops a methodology which can be used to form manufacturing cells using both a new similarity coefficient based on the number of alternative routes during machine failure and demand c...

Forming part families by using genetic algorithm and designing machine cells under demand changes

This study develops a methodology which can be used to form manufacturing cells using both a new similarity coefficient based on the number of alternative routes during machine failure and demand changes for multiple periods. The methodology is divided into two phases. A new similarity coefficient, which considers the number of available alternative routes when available during machine failure, is suggested in Phase I. The primary objective of Phase I is to identify part families based on the new similarity coefficient by using a genetic algorithm. One of the major factors contributing to the success of cell implementation is flexibility for demand changes. It is difficult to reorganize the cells according to changes in demand, available machine capacity, and due date. Most of the suggested approaches in the literature tend to use a fixed demand for cellular manufacturing systems. Due to demand changes, cell design should include more than the one period that most researchers of cellular manufacturing systems consider. A new methodology for cell formation, which considers the scheduling and operational aspects in cell design under demand changes, is introduced in Phase II. Machines are assigned to part families by using an optimization technique. This optimization technique employs sequential and simultaneous mixed integer programming models for a given period to minimize the total costs which are related to the scheduling and operational aspects.

Load balancing and resource reservation in mobile ad hoc networks

To ensure uninterrupted communication in a mobile ad hoc network, efficient route discovery is crucial when nodes move and/or fail. Hence, protocols such as Dynamic Source Routing (DSR) precompute alternate routes before a node moves and/or fails. In this paper, we modify the way these alternate routes are maintained and used in DSR, and show that these modifications permit more efficient route discovery when nodes move and/or fail. Our routing protocol also does load balancing among the number of alternate routes that are available. Our simulation results show that maintenance of these alternate routes (without affecting the route cache size at each router) increases the packet delivery ratio. We also show that our approach enables us to provide QoS guarantees by ensuring that appropriate bandwidth will be available for a flow even when nodes move. Towards this end, we show how reservations can be made on the alternate routes while maximizing the bandwidth usage in situations where nodes do not move. We also show how the load of the traffic generated due to node movement is shared among several alternate routes. In addition, we adaptively use Forward Error Correction techniques with our protocol and show how it can improve the packet delivery ratio.

Virtual Topology Design and Reconfiguration of Virtual Private Networks (VPNs) over All-Optical WDM Networks

This paper studies the virtual topology design and reconfiguration problem of virtual private networks (VPNs) over all-optical WDM networks. To support VPN service, a set of lightpaths must be established over the underlying WDM network to meet the VPN traffic demands and this set of lightpaths must also be dynamically reconfigurable in response to changing VPN traffic. To achieve good network performance and meet the service requirements of optical virtual private networks (oVPNs), we formulate the problem as an integer programming problem with multi-objectives and present a general formulation of the problem. In the formulation, we take into account the average propagation delay over a lightpath, the maximum link load, and the reconfiguration cost with objectives to minimize the three metrics simultaneously. The formulated problem is NP-hard and is therefore not practical to have exact solutions. For this reason, we use heuristics to obtain approximate optimal solutions and propose a balanced alternate routing algorithm (BARA) based on a genetic algorithm. To make the problem computationally tractable, we approximately divide BARA into two independent stages: route computing and path routing. At the route computing stage, a set of alternate routes is computed for each pair of source and destination nodes in the physical topology. At the path routing stage, an optimal route is decided from a set of alternative routes for each of the lightpaths between a pair of source and destination nodes. A decision is subject to the constraints and objectives in the formulation. To improve the computational efficiency, we use a genetic algorithm in BARA. Through simulation experiments, we show the effectiveness of BARA and the evolution process of the best solution in a population of solutions produced by the genetic algorithm. We also investigate the impact of the number of alternative routes between each pair of source and destination nodes on the optimized solutions.

A new travel cost approach based on network structures and taste variety

This study develops a travel cost function that considers with equal significance the distance between origin and destination, as well as the characteristics of alternative travel routes. These characteristics include the status of infrastructure, frequency of congestion and the traveler's taste for variety, which may lead to an increase in welfare as the number of alternative routes increases. The theoretical definition of travel cost is made up of two cost components: the expected variable cost component, which accounts for the cost of traveling on a specific route, and the network cost, which accounts for the sacrifices inherent in alternative possibilities of traveling in a specific network. The analysis of the model shows that an increase in the unitary travel price generates a proportional increase in the number of alternative routes for which the total travel cost within a specific network has a minimum. The proposed definition of the total travel cost demonstrates that, if more alternative network routes are offered, travelers are willing to pay higher travel costs due to their taste for variety.

Two Routes to Certification: What Do Student Teachers Think?

Alternate routes to certification have assumed increasing importance for teacher education since A Nation At Risk (National Commission on Excellence in Education, 1983) brought teaching and teacher education under public attack. There are an increasing number of alternate routes to teaching--including state, university and college, and district-based initiatives--as well as programs such as Teach for America (Feistritzer & Chester, 1998). Alternate routes may be linked to the university, but they typically seek to fast-track or circumvent traditional university-based teacher education. Some see alternate routes as a serious threat to university sponsored professional preparation (Roth, 1986). Others maintain that the issue is not over professional preparation per se but over the timing and institutional context for teacher preparation, and about the mix of professional knowledge and skills to be acquired (Stoddart & Floden, 1996, p. 90). Alternate routes are established for a variety of reasons (Feistritzer & Chester, 1998): to provide accessibility to the teaching workforce for nontraditional entrants, attract teachers to underserved geographical areas, recruit teachers for subject areas of perennial shortage such as science and math, attract high potential individuals who might otherwise pursue different careers (Darling-Hammond & Cobb, 1996). In California in particular, they have arisen to lessen the historical shortage of special education and bilingual teachers (Gunderson & Karage, 1992; Institute for Education Reform, 1996; McKibben & Schrup, 1995). In California, the Commission on Teacher Credentialing and teacher education programs at public and private institutions have historically discouraged the use of emergency permit teachers (EPTs) as an entry into teaching. The preferred route has been for preservice students to complete their field experiences, including student teaching, in the classrooms of credentialed teachers. However, beginning in 1996, class-size reduction opened hundreds of classrooms to alternate-route teachers, that is, teachers with little or no professional preparation prior to assuming teaching responsibilities. Districts no longer needed to show special hardship to put EPTs in classrooms (McKibben, 1996). A large percentage of EPTs are walk-ons, possessors of an undergraduate degree who have passed the required basic skills test but lack professional preparation. Some come from private and parochial schools seeking larger salaries and improved benefits; they bring teaching experience, but most are uncredentialed. A small number of people who left teaching years earlier are returning to the field, but their credentials long ago expired. Preservice program students who take emergency permit positions before they complete their professional preparation are a large source of uncredentialed teachers. In the changed climate of teacher hiring in California, preservice programs with the traditional structure of coursework followed by student teaching face the predicament of how to accommodate students who take emergency permit jobs before completing the program. Programs ask, How can student teaching be accomplished when the student is already a classroom teacher? How do traditional notions of student teaching conflict with program students who have skipped student teaching and begun teaching before program completion? What is the role of a university-supervised student teaching semester for program students who are classroom teachers of record, some of them teachers of several semesters' experience by the time they get to the student teaching phase of the program? In this article, we report a 2-year study of a preservice program that, since 1996, has used both emergency permit teaching and traditional student teaching as the culminating field experience in the professional preparation sequence. Our purpose in this study was to investigate the perceptions traditional student teachers (STs) and EPTs hold of their different ways of completing their professional preparation. …

Trends in antifungal research.

With the increasing use of aggressive immunosuppressive therapies in the management of a variety of patient populations, the continuing presence of the AIDS pandemic and the therapeutic advances employed in critical care settings, an increasing number of serious fungal infections are being encountered by today's practicing clinicians. Traditionally, antifungal drug therapy has been delivered by means of intravenous infusion, oral administration, or topical application. Recently, a number of alternative routes of antifungal drug delivery have been developed and investigated, and the traditional means of antifungal administration have been improved to facilitate the therapeutic use of new and reformulated antifungal agents. Organized based on the route of administration, this chapter reviews these advances in antifungal drug delivery.