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Cloud platforms and services usually provide an APIlayer as decoupled, language agnostic interface for both front-endclient integration and back-end data and/or function access. Theavailability and performance of the APIs have significant impact onthe quality of end user or client experiences due to its nature ofinteraction endpoints. However, the extreme dynamics, complexityand scale of the current...
The millimeter-wave (mmWave) bands, roughly referred to 30-300 GHz, have been widely recognized as a promising candidate for dense deployment of small- cells backhaul network. The dense small-cell deployment produces a huge amount of backhaul traffic, and directional communication poses a significant challenge. In this paper, we propose a dynamic frame reconfiguration scheme which provides greater...
One of key technologies of 5th generation mobile networks is introducing small cells, such as femtocells and picocells, to supplement existing macrocells, and this results in high heterogeneity in mobile networks. Cell association, which selects a base station for each user to connect to, is a fundamental issue to optimize the performance and utilization of heterogeneous networks. This paper develops...
This paper considers a problem of user and access point associations in heterogeneous wireless networks consisting of multiple radio access technologies. We propose a strategy for optimizing the problem that aims at maximizing the total minimal utility of users in the longer term. The minimal utilities can be obtained from bare essentials of the quality of experience and defined by considering different...
The mechanisms of allocating the resources in Long Term Evolution (LTE) cellular networks are very critical issues, because scheduling algorithms have the main responsibility for determining how to allocate radio resources for different users. In this work a dynamically adopted Proportional Fair (PF) scheduling strategy for capacity enhancement of LTE system is proposed. Performance comparison with...
In order to enhance the Long Term Evolution (LTE) network performance, the Third Generation Partnership Project (3GPP) introduced Coverage and Capacity Optimisation (CCO) in the context of Self Organising Network (SON). Antenna parameters (i.e. azimuth, electrical tilt etc.) play a key role in CCO and have a significant impact on the users' Quality of Service (QoS). In this paper, a novel metric,...
In order to enhance the Long Term Evolution (LTE) network performance, the Third Generation Partnership Project (3GPP) introduced Coverage and Capacity Optimisation (CCO) in the context of Self Organising Network (SON). Antenna parameters (i.e. azimuth, electrical tilt etc.) play a key role in CCO and have a significant impact on the users' Quality of Service (QoS). In this paper, a novel metric,...
A major problem in Wireless Mesh Network is capacity decrease due to wireless interference. A wireless mesh router with multiple routers and channels is capable of reducing network interference. Static channel allocation and dynamic channel allocation are types of channel allocation. Adaptive Dynamic Channel Allocation protocol (ADCA) is dynamic channel allocation protocol which decreases the packet...
The dynamic TDD DL/UL configuration based on instantaneous asymmetric DL/UL traffics is an effective way to increase the radio resource utilization. However, free reconfiguration of each cell's TDD DL/UL configuration may result in significant co-channel co-subframe DL-UL interference. In this paper, we propose and evaluate a novel centralized cell clustering interference mitigation scheme for dynamic...
In this paper a realization of the self-growing networks concept is developed by means of an adaptive algorithm that facilitates capacity and energy-efficient performance. The algorithm builds on two aspects of optimisation of the self-growing concept: goal-based optimisation and network-based optimisation. The former aspect elaborates on the performance of a network controlled by multi-objective...
Orthogonal Frequency Division Multiple Access (OFDMA), Multiple Input Multiple Output (MIMO), and Adaptive Modulation and Coding (AMC) are advanced signal processing techniques introduced in the wireless 3GPP LTE standard. In MIMO-OFDMA system, by taking advantage of the spatial dimension and depending on the time-varying wireless channel condition, the most efficient modulation and coding with spatial...
Technological advancements in wireless communications and embedded systems have led to the proliferation of wireless sensor network (WSN) applications, each with varying application requirements (i.e., lifetime, throughput, reliability, etc.). Sensor node tunable parameters enable WSN designers to specialize/tune a sensor node to meet application requirements, but however, parameter tuning is a challenging...
Automated configuration and management of highly dynamic networks is a challenging problem for network practitioners. Such online optimization of systems can be performed in two ways: (i) using a separate model of the system for experimenting new configurations, (ii) using the system itself for experimentation without a separate system model. The former approach fails for dynamic networks with high...
Opportunistic spectrum access, which allows secondary users opportunistically access unused licensed channels to exploit instantaneous spectrum availability, is a promising approach to achieve efficient spectrum utilization and mitigate spectrum scarcity. To address the challenge of dynamic spectrum access, one of the most important issues is cooperative spectrum reallocation among secondary users...
Quality-aware service composition starts from an abstract workflow. The tasks of the workflow are associated with functional types for which concrete services can be retrieved from a registry. Abstract tasks have to be mapped to concrete services before the workflow is executed. The goal is to maximize the workflow quality by choosing the right combination of services. Spending more time in discovery...
We present JAWS, a job-aware, data-driven batch scheduler that improves query throughput for data-intensive scientific database clusters. As datasets reach petabyte-scale, workloads that scan through vast amounts of data to extract features are gaining importance in the sciences. However, acute performance bottlenecks result when multiple queries execute simultaneously and compete for I/O resources...
On chip multiprocessors (CMPs) platforms, multiple co-scheduled applications can severely degrade performance and quality of service (QoS) when they contend for last-level cache (LLC) resources. Whether an application will impose destructive interference on co-scheduled applications is largely dependent on its own inherent cache access behavior characteristics. In this work, we first present case...
Service Oriented Architectures enable markets of functionally equivalent service providers delivering services at different Quality of Service (QoS) and cost levels. Under these circumstances, there is a need for mechanisms to optimally select service providers at run-time to support a business process execution so that a utility function for the business process is maximized subject to QoS and cost...
Throughput optimization and traffic engineering in Wavelength-Division Multiplexing (WDM) networks are usually treated as mono-objective optimization problems. In this paper, we provide a multi-objective Integer Linear Program (ILP) for the joint throughput optimization and traffic engineering problem. By simultaneously i) maximizing the throughput, ii) minimizing the resource consumption, and iii)...
Current disk arrays consist purely of hard disk drives, which normally provide huge storage capacities with low cost and high throughput for data-intensive applications. Nevertheless, they have some inherent disadvantages such as long access latencies and energy inefficiency due to their build-in mechanical mechanisms. Flash-memory-based solid state disks, on the other hand, although currently more...
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