The High-Energy Lightcurve Generator (HILIGT) is a new web-based1 tool which allows the user to generate long-term lightcurves of X-ray sources. It provides historical data and calculates upper limits from image in real-time. HILIGT utilizes twelve satellites, both modern missions such as XMM-Newton Swift, earlier facilities ROSAT, EXOSAT, Einstein or Ariel V. Together, this enables query 50 ye...

Recent works show that power-proportional data centers can save energy cost by dynamically adjusting active servers based on real time workload. The data center activates servers when the workload increases and transfers servers to sleep mode during periods of low load. In this paper, we investigate the right-sizing problem with heterogeneous data centers including various operational cost and ...

Virtualization-based server consolidation has been proven to be an ideal technique to solve the server sprawl problem by consolidating multiple virtualized servers onto a few physical servers leading to improved resource utilization and return on investment. In this paper, we solve this problem by using existing servers, which are heterogeneous and diversely preferred by IT managers. Five pract...

Query Integrator System (QIS) is a database mediator framework intended to address robust data integration from continuously changing heterogeneous data sources in the biosciences. Currently in the advanced prototype stage, it is being used on a production basis to integrate data from neuroscience databases developed for the SenseLab project at Yale University with external neuroscience and gen...

We study the dynamic assignment of flexible servers to stations in the presence of setup costs that are incurred when servers move between stations. We focus on tandem lines with two stations and two servers with the goal of maximizing the long-run average profit. We investigate how the optimal server assignment policy for such systems depends on the magnitude of the setup costs, as well as on ...

We consider two heterogeneous server with catastrophe and restoration. The servers have service rate μ1 for 1 μ2 2 (μ1 ≠ μ2). Server is always obtainable intermittently obtainable. must first finish his in hand service. This model solved by Matrix Geometric Method(MGM). Some numerical results are also presented.

An adaptive cache proxy is developed to improve the performance of web access in soft real-time applications. It consists of client proxies and cooperative proxy servers with a server-side pushing schema. The large amount of heterogeneous data will be stored in the proxy servers and delivered to clients through computer networks to reduce the response time and network traffic. The adaptive prox...

In this paper, we study an M/M/2 queueing system with balking and two heterogeneous servers, Server 1 and Server 2. Customers arrive according to a Poisson process and form a single waiting line. Two parallel servers provide heterogeneous exponential service to customers on a firstcome first-served basis. It is assumed that Server 1 is perfectly reliable and Server 2 is subject to breakdowns. F...

The problem of optimal jobs assignment to heterogeneous servers arises in many applications. The problem of optimal jobs assignment for two heterogeneous servers with respect to minimization of long run average mean number jobs in the system was considered in [1], where it was shown that the policy, which minimizes the number of customers in the system, has a threshold property and consists in ...

Due to the users’ mobility, new online applications, as well low processing power and limited energy of smart devices, traditional cloud computing models could not provide required services. Cloud service providers improve quality their services by moving some servers edge network closer mobile users. Considering nature users heterogeneous demands in different areas, optimal placement plays an ...