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Cavernous Hemangiomas (CH) arise from any part of the cerebrum. Intraventricular lesions are rare and pure third ventricular localization is rare for CHs. Cavernomas of the ventricles may present with bleeding or signs associated with hydrocephalus. Radical excision is advocated for optimal management of cavernomas.

Scheduling is a central operation to achieve "green" data centers, i.e., distributing diversified workloads across heterogeneous resources in an energy efficient manner. Taking an opposite perspective from most of the related work, this paper reveals the "brown" side of scheduling, i.e., wasted core seconds (so called brown resources), using fleld analysis and trace-driven simulation of a Google cluster trace. First, based on the trace, we pinpoint the dependency between priority scheduling and task eviction that causes brown resources and present a brief characterization study focusing on workload priorities. Next, to better understand and further reduce the resource "inefficiency" of priority scheduling, we develop a slot-based scheduler and simulator with various system tunable parameters. Our key finding is that tasks of low priority suffer greatly in terms of response time as well as CPU resources because of a high probability of being evicted and resubmitted. We propose to use simple threshold-based policies that consider the trade-off between task drop rates and wasted core seconds due to task resubmission due to eviction. Our experimental results show that we are able to effectively mitigate brown resources without sacrificing the performance advantages of priority scheduling.

This paper describes and discusses a heterogeneous system of satellite and IEEE 802.16 WiMAX networks collaborating for the efficient delivery of multimedia services. We first elaborate on the rationale behind integrated satellite and WiMAX networks with an overview of current research on interworking of satellite and 3G/Beyond 3G terrestrial networks. Following this background, we propose a diverse set of enhancements and additions into WiMAX Base Station (BS) and Multicast Broadcast Service Controller (MBSC), which allows this interworking in the multimedia delivery context. We describe a WiMAX BS downlink scheduler that considers satellite channel conditions of the dual‐mode SSs (Subscriber Station) while making resource allocation and packet scheduling. This scheduler interacts with another proposed module in MBSC, namely Satellite–Terrestrial Interaction Module, for performing these operations. Traffic for real‐time multimedia and cache‐based delivery is considered in the system. On the SS side, a lightweight signaling scheme between BS and SS for service continuity and control is presented. Copyright © 2010 John Wiley & Sons, Ltd.

In order to optimize the network resources, we should incorporate all the available information into the network design. However, incorporating irrelevant information may increase the design complexity and/or decrease the performance of the network. In this paper, we investigate the relevance of integrating the scene length characteristics of moving pictures expert group (MPEG) coded video bitstreams into a direct broadcast satellite (DBS) network with return channel system (DVB‐RCS). Due to the complexity of the studied system, unless disputable simplifications are made, it is hard to achieve a mathematical foundation for this integration. Our analysis relies on extensive set of simulations. Firstly, we achieve the scene length distributions for MPEG bitstreams based on the proposed scene change models and their subjective observations of the actual video. We show that these models may be used to estimate the scene length of MPEG bitstreams. We then integrate this estimation into a DBS network simulator. Finally, we show that the scene length characteristics may be used to improve the DBS network performance under certain conditions. Copyright © 2004 John Wiley & Sons, Ltd.

In order to optimize the network resources, we should incorporate all the available information into the network design. However, incorporating irrelevant information may increase the design complexity and/or decrease the performance of the network. In this paper, we investigate the relevance of integrating the scene length characteristics of moving pictures expert group (MPEG) coded video bitstreams into a direct broadcast satellite (DBS) network with return channel system (DVB-RCS). Due to the complexity of the studied system, unless disputable simplifications are made, it is hard to achieve a mathematical foundation for this integration. Our analysis relies on extensive set of simulations. Firstly, we achieve the scene length distributions for MPEG bitstreams based on the proposed scene change models and their subjective observations of the actual video. We show that these models may be used to estimate the scene length of MPEG bitstreams. We then integrate this estimation into a DBS network simulator. Finally, we show that the scene length characteristics may be used to improve the DBS network performance under certain conditions. Copyright © 2004 John Wiley & Sons, Ltd.

Adaptive rate control, if properly employed, is an effective mechanism to sustain acceptable levels of Quality of Service (QoS) in wireless networks where channel and traffic conditions vary over time. In this paper we present an adaptive rate (source and channel) control mechanism, developed as part of an Adaptive Resource Allocation and Management (ARAM) algorithm, for use in Direct Broadcast Satellite (DBS) networks. The algorithm performs admission control and dynamically adjusts traffic source rate and Forward Error Correction (FEC) rate in a co-ordinated fashion to satisfy QoS requirements. To analyze its performance, we have simulated the adaptive algorithm with varying traffic flows and channel conditions. The traffic flow is based on a variable bit rate (VBR) source model that represents Motion Picture Expert Group (MPEG) traffic fluctuations while the DBS channel model is based on a two-state Additive White Gaussian Noise (AWGN) channel. For measures of performance, the simulator quantifies throughput, frame loss due to congestion during transmission as well as QoS variations due to channel (FEC) and source (MPEG compression and data transmission) rate changes. To show the advantage of the adaptive FEC mechanism, we also present the performance results when fixed FEC rates are employed. The results indicate significant throughput and/or quality gains are possible when the FEC/source pairs are adjusted properly in co-ordination with source rate changes.