An internet—bad logistics management system for enterpri chains
N. Prindezis， C。T. Kiranoudis
School of Chemical Engineering， NationalTechnicalUniversity， 15780 Athens， Greece
丝瓜汤
Received 13 September 2003； received in revid form 20 December 2003; accepted 27 January 2004
Available online 10 December 2004
Abstract
This paper prents an Internet-Bad Logistics Management System to coordinate and disminate tasks and related information for solving the heterogeneous vehicle routing problem using appropriate metaheuristic techniques， for u in enterpri chainnetworks。 Its architecture involves a JAVA Web applet equipped with interactive communication capabilities between peripheralsoftware tools. The system was developed i
n distributed software fashion technology for all computer platforms utilizing a Webbrowr， focusing on the detailed road network of Athens and the needs of the Athens Central Food Market enterpris. 2004 Elvier Ltd。 All rights rerved.
Keywords: Decision support system； e-Logistics； Transportation; Vehicle routing problem
任职以来工作总结1.Introduction
Enterpri chains are the business model of the prent and future regarding markets that involve small andmedium company sizes. Clearly, grouping activities towards a focud target facilitates an understandably improved market penetration guaranteed by a successfultrademarkofaleadingcompanyinthefield.Several collaboration models that basically include franchising areintroduced as a part of this integrated process. Whensuch a network is introduced in order to exploit acommercial idea or business initiative and subquentlyexpanded as market penetration grows， veral management issues ari regarding the operations of the entirenetwork。 Such a networ
k is the ideal place for organizing and evaluating in a more centralized way veral ordinary operations regarding supply chain and logisticsInfact，toolsdeveloped fororganizingmanagementprocess and operational needs of each individual company, can be developed in a more centralized fashionand the rvices provided by the tool can be offered toeach network member to facilitate transactions andtackle operations similarly。 Web—bad applicationsare an ideal starting place for developing suchapplications.Typically such systems rve as a central depot fordistributing common rvices in the field of logistics.The commercial application is stored in a central rverand rvices are provided for each member of the group.A prototype of such a rver is described in a previouswork (Prindezis, Kiranoudis， & Marinos-Kouris,2003).Thispaperprentsthecompletedinternetsystemthat is installed in the central web rver of the AthensCentral Food Market that deals with the integratedproblemofdistributionfor690companiesthatcompria unique logistics and retail chain of enterpris。 Theneeds of each company are underlined and the algorithms developed are described within the unified internet environment. The problem solved and
rvicesprovidedforeachcompanyistheoneinvolvingdistribution of goods through a heterogeneous fleet of trucks.New insights of the metaheuristics employed are provided。 A characteristic ca study is prented to illustrate the eff利马窦建筑施工员ectiveness of the propod approach for a real-world problem of distribution through the detailedroad network of Athens。
2. Distribution through heterogeneous vehicle fleets重要的英文
The fleet management problem prented in this paper requires the u of a heterogeneous fleet of vehiclesthat distribute goods through a network of clients
(Tarantilis， Kiranoudis， & Vassiliadis， 2003， 2004）。Therefore, the system was designed in order to automatically generate vehicle routes (which vehicles should de—运行在哪里打开
liver to which customers and in which order)， usingrational, quantitative， spatial and non-spatial information and minimizing simultaneously the vehicle costand the total distance travelled by the vehicles, subjectto the following constraints：
●each vehicle has a predetermined load capacity， typically different from all other vehicles comprising thefleet (heterogeneous nature),
●the capacity of a vehicle cannot be exceeded，
●a single vehicle supplies each customers demand,
●the number of vehicles ud is predetermined。
The problem has an obvious commercial value and hasdrawntheattentionofORcommunity.Itsgreatsuccess can be attributed tothe fact that it isa very interesting problem both from the practical and theoreticalpoints of view. Regarding the practical point of view,the distribution problem involved definitely plays a centralroleintheefficiencyoftheoperationalplanninglevelof distribution management， producing economicalroutes that contribute to the reduction of distributioncosts, offering simultaneously significant savings in allrelated expens （capital, fuel costs， driver salaries）。 ItsImportanceinthepracticallevel，motivatedintentheoretical work and the development of efficientalgorithms.
FortheproblembyacademicrearchersandprofessionalsocietiesinOR/MS，resultinginanumberofpapersconcerningthedevelopmentofanumberofVehicleRoutingInformation Systems (VRIS） for solving the problem。The problem discusd is an NP—hard optimizationproblem, that is to say the global optimum of the problem can only be revealed through an algorithm of exponentialtimeorspacecomplexity withrespecttoproblemsize。 Problems of this type are dealt with heuristic ormetaheuristic techniques。 Rearch on the developmentof heuristic algorithms （Tarantilis ＆ Kiranoudis， 2001,2002a, 2002b） for the fleet management problem hasmade considerable progress since the first algorithmsthat were propod in the early 60s。 Among them, tabuarch is the champion (Laporte, Gendreau， Potvin， &Semet，2000）. The most powerful tabu arch algorithmsare now capable of solving medium size and even largesize instances within extremely small computationalenvironments regarding load and time. On the algorithmic side， time has probably come to concentrate on thedevelopment of faster， simpler (with few parameters）and more robust algorithms, even if this caus a smallloss in quality solution. The attributes are esntial ifan algorithm is to be implemented in a commercialpackage.
The algorithm beyond the system developed is oftabu arch nature。 As mentioned before, since the algorithms cannot reveal the guaranteed global optimum，the time that an algorithm is left to propo a solutionto the problem is of utmost importance to the problem.Certainly, there is a trade-off between time expected forthe induction of the solution and its quality。 This partwas implementedinastraightforwardway.Ifthesystemis asked by the ur to produce a solution of very highquality instantly， then an aggressive strategy is to beimplemented。 If the ur relaxes the time of solution tobe obtained, that is to say if the algorithm is left toarch the solution space more effciently， then there isroom for more elaborate algorithms.
老鸭汤做法
The algorithm employed has two distinct parts. Thefirst one is a generalized route construction algorithmthat creates routes of very good quality to be improvedby the subquent tabu pha。 The construction algorithm takes into account the peculiarities of the heterogeneous nature of fleet and the desire of the ur to uvehicles of his own desire, owned or hired, according tohis daily needs。
