Software systems are a typical kind of man-made complex systems. Understanding their evolutions can lead to better software engineering practices. In this paper, the authors use complex network theory as a tool to ana...
详细信息
Software systems are a typical kind of man-made complex systems. Understanding their evolutions can lead to better software engineering practices. In this paper, the authors use complex network theory as a tool to analyze the evolution of object-oriented (OO) software from a multi-granularity perspective. First, a multi-granularity software networks model is proposed to represent the topological structures of a multi-version software system from three levels of granularity. Then, some parameters widely used in complex network theory are applied to characterize the software networks. By tracing the parameters' values in consecutive software systems, we have a better understanding about software evolution. A case study is conducted on an open source OO project, Azureus, as an example to illustrate our approach, and some underlying evolution characteristics are uncovered. These results provide a different dimension to our understanding of software evolutions and also are very useful for the design and development of OO software systems.
Service oriented environments are computer network systems that are highly dynamic and change with time. Entities in such environments have different security needs from services. Management of security information in...
详细信息
Traditional low-power wireless protocols maintain distributed network state to cope with link dynamics. Modeling the pro- tocol operation as a function of network state is dificult as the state is frequently updated i...
详细信息
ISBN:
(纸本)9781450320276
Traditional low-power wireless protocols maintain distributed network state to cope with link dynamics. Modeling the pro- tocol operation as a function of network state is dificult as the state is frequently updated in an uncoordinated fashion. Recent protocols use synchronous transmissions (ST): mul- tiple nodes send simultaneously towards the same receiver, as opposed to pairwise link-based transmissions (LT). ST en- able eficient multi-hop protocols with little network state. We studied whether ST in Glossy enable simple yet accu- rate protocol modeling [10]. Based on extensive testbed experiments and statistical analyses, we found that: (i) unlike LT, packet receptions and losses with ST largely adhere to a sequence of independent and identically distributed (i.i.d.) Bernoulli trials;(ii) this property greatly simplifies accurately modeling ST-based protocols, as we demonstrated by obtaining model errors below 0.25% in energy for the Glossy based Low-Power Wireless Bus (LWB).
Inferring abnormal glucose events such as hyperglycemia and hypoglycemia is crucial for the health of both diabetic patients and non-diabetic people. However, regular blood glucose monitoring can be invasive and incon...
详细信息
In this paper, we propose an energy-efficient cooperative geographic routing (ECGR) to reach energy-efficient routing in wireless sensor networks (WSN). ECGR takes full advantage of cooperative diversity and geographi...
详细信息
In this paper, we propose an energy-efficient cooperative geographic routing (ECGR) to reach energy-efficient routing in wireless sensor networks (WSN). ECGR takes full advantage of cooperative diversity and geographic routing. At physical layer, cooperative nodes transmit the same packet in a cooperative way to achieve farther transmission distance of each hop without more energy consumption. While at the network layer, ECGR adaptively selects the appropriate cooperative nodes to form forwarding clusters to forward the packet to the destination when we consider energy consumption and geographic information of the sensor nodes. Meanwhile, in order to fully assess the energy consumption, we take circuit energy consumption of the sensor nodes into consideration. According to the description above, we increase the transmit distance of each hop; and thereby reducing and balancing the overall network energy consumption among nodes to extend the lifetime of the network.
With the vast number of isolated and independent Cloud Service Providers (CSP) existing at present, it is challenging for the users to choose an appropriate CSP. In this paper, we propose two Multiple-Cloud orchestrat...
详细信息
Of late, there has been a considerable interest in generic and configurable System-on-Chip platforms specifically targeted towards implementing multimedia applications. A number of such platforms offer the possibility...
详细信息
This paper focuses on an environment of more than one proxy server that serve homogeneous or even heterogeneous client preferences for streaming of video files. Under a hierarchical tree topology system of proxies, th...
详细信息
ISBN:
(纸本)1595935053
This paper focuses on an environment of more than one proxy server that serve homogeneous or even heterogeneous client preferences for streaming of video files. Under a hierarchical tree topology system of proxies, the prefixes of the videos are stored in small size proxy caches each located very close to the corresponding client community, while larger caches located further away from the client communities are used to cache the latter segments of the videos requested by more than one client community. Frequency-Based Cache Management Policies are used in order to efficiently and dynamically cache the content of the most popular videos among the various proxies. Our event-driven simulations have shown that the hierarchical tree topology of proxies achieves a much higher byte-hit ratio with less cache management overhead, when using the same overall cache capacity with a simple topology of independent proxies and in general provides better performance characteristics. Copyright 2006 ACM.
This examination comprises a digital analysis of the real-time capability of Bluetooth to meet the requirements of the automation field, using ACL and SCO communication channels. The bit error ratio is taken as basic ...
详细信息
ISBN:
(纸本)0889865906
This examination comprises a digital analysis of the real-time capability of Bluetooth to meet the requirements of the automation field, using ACL and SCO communication channels. The bit error ratio is taken as basic characterizing indicator for the evaluation of the reliability of the communication channels. The delay time, its variation and the corresponding jitter provide a basis to review the time behaviour. Cambridge Silicon Radios (CSR) Bluetooth chips of type BlueCore 2 and BlueCore 4 were used. Several configurations with and without activation of quality of service (QoS) have been investigated regarding delay and jitter. For the basic communication channel's description and classification in terms of burst error behaviour, the well known Gilbert-Elliott model was used. Their parameters were gained by estimations using the Baum-Welch algorithm. These practical relevant parameters of the model can be used for the development and evaluation of channel codes and safety protocols within realistic simulations.
Cooperative communication can achieve spatial diversity gains,and consequently combats signal fading due to multipath propagation in wireless networks powerfully.A novel complex field network-coded cooperation(CFNCC...
详细信息
Cooperative communication can achieve spatial diversity gains,and consequently combats signal fading due to multipath propagation in wireless networks powerfully.A novel complex field network-coded cooperation(CFNCC) scheme based on multi-user detection for the multiple unicast transmission is *** analysis and simulation results demonstrate that,compared with the conventional cooperation(CC) scheme and network-coded cooperation(NCC) scheme,CFNCC would obtain higher network throughput and consumes less time ***,a further investigation is made for the symbol error probability(SEP) performance of CFNCC scheme,and SEPs of CFNCC scheme are compared with those of NCC scheme in various scenarios for different signal to noise ratio(SNR) values.
暂无评论