A Lazy Version of Eppstein’s K Shortest Paths Algorithm

Jiménez, Víctor M.; Marzal, Andrés

doi:10.1007/3-540-44867-5_14

Cited by 39 publications

(28 citation statements)

References 13 publications

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“…For method Rkg and for the Phase 2 of method SP, a k-best algorithm is needed. We have used a modified version of Eppstein's algorithm [24] proposed by Jiménez and Marzal [25]. The results obtained are summarized in Tables 1, 2, 3 and 4.…”

Section: Resultsmentioning

confidence: 99%

Exact Methods for Computing All Lorenz Optimal Solutions to Biobjective Problems

Galand¹,

Lust²

2015

Algorithmic Decision Theory

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Abstract. This paper deals with biobjective combinatorial optimization problems where both objectives are required to be well-balanced. Lorenz dominance is a refinement of the Pareto dominance that has been proposed in economics to measure the inequalities in income distributions. We consider in this work the problem of computing the Lorenz optimal solutions to combinatorial optimization problems where solutions are evaluated by a two-component vector. This setting can encompass fair optimization or robust optimization. The computation of Lorenz optimal solutions in biobjective combinatorial optimization is however challenging (it has been shown intractable and NP-hard on certain problems). Nevertheless, to our knowledge, very few works address this problem. We propose thus in this work new methods to generate Lorenz optimal solutions. More precisely, we consider the adaptation of the well-known two-phase method proposed in biobjective optimization for computing Pareto optimal solutions to the direct computing of Lorenz optimal solutions. We show that some properties of the Lorenz dominance can provide a more efficient variant of the two-phase method. The results of the new method are compared to state-of-the-art methods on various biobjective combinatorial optimization problems and we show that the new method is more efficient in a majority of cases.

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Section: Resultsmentioning

confidence: 99%

Exact Methods for Computing All Lorenz Optimal Solutions to Biobjective Problems

Galand¹,

Lust²

2015

Algorithmic Decision Theory

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“…La lista de N -best se genera mediante sucesivas llamadas a este método. Implementa el algoritmo de Eppstein [Eppstein, 1998] para los K mejores caminos en problemas de programación dinámica, concretamente implementa su versión Lazy [Jiménez & Marzal, 2003].…”

Section: Identificador Del Vérticeunclassified

“…getOutputWordGraph: devuelve un grafo que contiene las N mejores hipótesis, de nuevo generado a través del algoritmo de Eppstein [Eppstein, 1998;Jiménez & Marzal, 2003]. …”

Section: Identificador Del Vérticeunclassified

“…Este módulo genera un trellis completo de la búsqueda, de tal forma que una vez finalizado el proceso es posible obtener tanto el mejor camino, como los N mejores. Para la lista de N -best se utiliza una implementación eficiente del algoritmo de Eppstein [Eppstein, 1998;Jiménez & Marzal, 2003]. …”

Section: Descripción General Del Procedimiento De Bús-quedaunclassified

“…This step outputs the 1-best, an N -best list, or a word graph following the Eppstein algorithm [Eppstein, 1998;Jiménez & Marzal, 2003]. GIATI technique allows to use the N -gram bilingual translation LM as a stochastic finite state transducer that generates the output sentenceȳ given the best sequence of tuplesx.…”

Section: Contributions To Sequence Recognitionmentioning

confidence: 99%

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Aportaciones al modelado conexionista de lenguaje y su aplicación al reconocimiento de secuencias y traducción automática

Martínez¹,

Julián²

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A Josepa por apoyarme en estos últimos años de escritura. A mis padres, Natividad y Crescencio, y hermanos, José y Nati, por creer en mí. AGRADECIMIENTOSQuiero aprovechar este espacio para agradecer el apoyo, críticas, y buenas intenciones que he encontrado en la gente en el camino de obtener el título de Doctor. Doy las gracias a mis amigos de Aldaia, que he tenido muy olvidados en estos últimos años, pero que siguen confiando en mí. A Germán, Jorge y Jesús compañeros de andadura durante la carrera, y compañeros en el doctorado, gracias por las discusiones, comentarios, curiosidades y demás cosas que he podido aprender con vosotros. A Lucena, Ximo, Carlos, Julien, Fidel, Antonio, Pablo por los años de música y conciertos. A Noelia por acompañarme durante un tiempo en la vida solapado con esta tesis. A Salva por estos años haciendo guía y ayudando en todo lo que ha podido siempre, aportando un punto de vista original, implicados ambos en la programación del software aquí utilizado. A María José por la dirección desde mi proyecto final de carrera, hasta el final con las sucesivas correcciones que esta tesis ha necesitado para ser lo que es. A Jon, Emilio y Encarna por su apoyo en diferentes ocasiones para encontrar trabajo. A la gente que ha pasado por el laboratorio L302, Sergio, David, Joan, Marcos, Lucía, Ximo, por su amistad. A la gente del departamento de Ciencias Físicas, Matemáticas y de la Computación de la Universidad CEU Cardenal Herrera, donde actualmente estoy trabajando, por haberme dado la oportunidad de poder poner un pie en el mundo de la enseñanza universitaria, a Javi, Nuria Rosillo, Juan, Pablo, Rafa Pérez, Rafa Ramírez, Nuria Llull, Manolo, Luís, Victor, Jordi, Antonio, Fernando, que juntos nos esforzamos por dar lo mejor en clase, y que me han ofrecido toda su confianza para que termine esta tesis. A los alumnos Fran, Joan, Vicent y Jose Manuel por implicarse en la competición del SWERC, que tanto disfruto. A la gente del DSIC, así como a gente del ITI, que he ido conociendo estos años. A Renato de Mori por su valiosa aportación a este trabajo. A la gente del LIUM en Le Mans, Patrik, Loïc, Kashif, Benoit, por ofrecerme su amistad durante mi estancia veraniega del 2010 en su universidad, y por supuesto a Holger Schwenk por acogerme y apoyar mis ideas. A Maxim por introducirme en el mundo de la traducción automática, y Josep María por recibirme en aquel verano del 2010. Al antiguo grupo IAM de la Universidad de Bern, Volkmar Frinken, Andreas Fischer y Horst Bunke, por los trabajos colaborativos que han dado una mayor profundidad a los resultados presentados en esta tesis. A todos aquellos de los que puede que me olvide que han repercutido de alguna forma en este trabajo, y que me han apoyado para llegar hasta aquí. A todos vosotros, ¡Gracias! V RESUMEN El procesamiento del lenguaje natural es un área de la inteligencia artificial, en particular, del reconocimiento de formas. Es un campo multidisciplinar que estudia el lenguaje humano, tanto oral como escrito. Se ocupa de la formulación e invest...

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A methodology for schedule‐based paths recommendation in multimodal public transportation networks

Canca

Zarzo

González‐R

et al. 2012

J of Advced Transportation

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This paper analyzes the problem of intermodal itineraries recommendation in interurban networks where different public transportation modes, several companies, time, and capacity constraints, as well as seat booking, are considered. The inherent network optimization problem is first modeled for a generic user request, and then a solving method that makes use of a network graph transformation is proposed. For each request, this solving method is based on pruning the user-specific time-space graph, followed by the application of a k-shortest path algorithm. Moreover, in order to build on-demand real-time itineraries recommendations, the algorithm has been embedded in a Web client-server to which users ask for trip recommendations by Internet or mobile phone. Finally, as an illustration, the proposed approach has been tested on the Andalusia main transportation network. ATIS and APTS have been analyzed by many authors, from both a theoretical and technical point of view. Yang and Meng [4] studied the price of using and the benefits gained from ATIS services as two key factors in explaining the growth of adoption of ATIS products. Horn [5] proposed a modeling framework to analyze the performance of urban passenger transport systems, with particular attention to demand-responsive transport modes and traveler information technologies. Levinson [6] and Kenyon and Lyons [7] considered the value of ATIS for route choice and its potential contribution to modal change, respectively. Yin et al.[8] studied how Intelligent Transportation Systems technologies can improve traffic congestion levels in urban road networks. They analyzed the impact that ATIS may play in route choice and departure time decisions. Most of these works are focused on the use of information systems in the private vehicle case. Concerning to the public case, several authors have studied different issues of ATIS and APTS focused on different topics such as users assessment (see e.g., [9] or [10]), congestion costs [11], or technology sourcing evaluation [12]. A recent point of interest has been the integration of ATIS into Web applications (see [13][14][15][16]).Roughly speaking, traveler public information systems have two main aims (see e.g., [17] or [18]). First, they should contribute to minimize the inconvenience of using public transport, simplifying the journey-planning and executing processes. Second, their design should be addressed to diminish the sense in which such a journey is disjointed and awkward, in such a way that the intermodal travel experience becomes closer to that of a journey by private car. To succeed in this latter aim, an accurate and efficient way to manage transfers is needed because, as pointed out in [19], transfers are one of the most important inconveniences perceived by users of multimodal transport systems.At this point, it is clear that, besides the appropriate infrastructure properties of the network, good and well-oriented information becomes also necessary in order to guarantee intermodality success [20]. Moreover...

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A Lazy Version of Eppstein’s K Shortest Paths Algorithm

Cited by 39 publications

References 13 publications

Exact Methods for Computing All Lorenz Optimal Solutions to Biobjective Problems

Exact Methods for Computing All Lorenz Optimal Solutions to Biobjective Problems

Aportaciones al modelado conexionista de lenguaje y su aplicación al reconocimiento de secuencias y traducción automática

A methodology for schedule‐based paths recommendation in multimodal public transportation networks

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