Plash Introduction

Welcome to PLASH website


PLASH Published Location-based Services

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ANTrip 雲水途誌

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ANTrip 網站管理平台

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The Platform for Location Aware Services with Human computation (PLASH) is a composite project consisting of the development of a supporting platform and application systems. The supporting platform provides a set of programming interfaces and management tools for application builders and service providers. The fundamental services and programming interfaces provided by this platform facilitate the development and hosting of PLASH applications. Furthermore, the server management tools help service providers set up and configure their PLASH application servers.


Based on the PLASH platform, we developed several mobile applications along with the supporting services hosted in the platform.


The supporting platform for PLASH applications (hereafter “PLASH platform”) consists of three layers. This multi-layer design aims to simplify the complexity of the application system. The first layer is the communication layer which provides fundamental data transmission services to the upper layers. We deployed various wireless technologies (e.g., WLAN, WiMax, and 3G) and communication structures (e.g, Vehicle to Infrastructure, Vehicle to Vehicle, or Vehicle to Mobile device) in this layer. On top of the first layer is the data layer responsible for data representation, storage and access. Currently this layer includes three databases to maintain user information, a friend list and geo-location data, and two processors to handle both geo-queries and data pre-processing. The last layer is the Service Layer which is the upper-most layer that application developers directly interact with. It provides fundamental services and basic applications. Data exchange and message delivery between any two layers are done via interfaces provided in each layer. We also implemented APIs in every layer to provide modulization and extensibility.


The communication layer is implemented by developing two communication services that support V2I (vehicle to infrastructure) and V2V (vehicle to vehicle) respectively. The programming languages adopted include C/C++ and Java. C/C++ provides the ability to efficiently control wireless hardware components and enable optimized memory management. Java is used to wrap and manage C/C++ components and implement interfaces in this layer since it is the primary language used in data and service layers. As for the hardware part, wireless equipment from various brands was tested for performance comparisons.


The data layer is powered by three SQL servers. We selected PostgreSQL to be the particular implementation of our SQL servers. The choice of PostgreSQL enables us to deploy PostGIS, which is a geographic information system specially designed for handling geographic data exclusively for PostgreSQL, in our databases. A set of access managers and access interfaces are implemented to help the collaborations between these layers.


The recent advances in information and communication technologies (ICT) and the steep drop of hardware prices have triggered the rapid deployments of various wireless networks. The capability of CPE which has been greatly enhanced enables low-end PCs to be equipped with multiple radio interfaces. While voice services dominating the wireless service, the gradual gain in popularity of Internet access and multimedia services has boosted the wireless-related industry. The rapid expansion of network infrastructures in recent years, from GSM, GPRS, WiFi, EDGE, WCDMA to WiMAX and LTE, would not be sustainable if no new services were introduced to attract more users. Especially when the infrastructure upgrade is not likely due to various reasons, the introduction of new service to prosper the wireless and related industries becomes crucially important.


The Platform for Location Aware Service with Human Computation (PLASH), based on the above belief, is proposed as a platform to allow fast deployment of various location aware services. This project is a collection of sub-projects that investigate various topics, problems and algorithms about location aware services, human computation, software framework, routing, network performance, city profiling, data mining as well as traffic estimation and recommendations. The PLASH project involves the joint efforts of six research teams led by seven notable computing scientists and scholars from Academia Sinica.


PLASH applies Web2.0 and human computation to consolidate the intelligence and efforts of the general public, which is the main difference with the traditional intelligent transportation system and location aware services. Human computation is the art of using massive groups of networked human/intelligent beings to solve problems that computers cannot. Therefore, the main concerns of design are different from the previous systems. In PLASH, users are also participators and contributors. PLASH will investigate the application of human computation in wireless services and demonstrate successful application.