A Self-adaptive Agent-based System for Cloud Platforms

Cloud computing is a model for enabling on-demand network access to a shared pool of computing resources, that can be dynamically allocated and released with minimal effort. However, this task can be complex in highly dynamic environments with various resources to allocate for an increasing number of different users requirements. In this work, we propose a Cloud architecture based on a multi-agent system exhibiting a self-adaptive behavior to address the dynamic resource allocation. This self-adaptive system follows a MAPE-K approach to reason and act, according to QoS, Cloud service information, and propagated run-time information, to detect QoS degradation and make better resource allocation decisions. We validate our proposed Cloud architecture by simulation. Results show that it can properly allocate resources to reduce energy consumption, while satisfying the users demanded QoS

Intelligent agent for formal modelling of temporal multi-agent systems

Software systems are becoming complex and dynamic with the passage of time, and to provide better fault tolerance and resource management they need to have the ability of self-adaptation. Multi-agent systems paradigm is an active area of research for modeling real-time systems. In this research, we have proposed a new agent named SA-ARTIS-agent, which is designed to work in hard real-time temporal constraints with the ability of self-adaptation. This agent can be used for the formal modeling of any self-adaptive real-time multi-agent system. Our agent integrates the MAPE-K feedback loop with ARTIS agent for the provision of self-adaptation. For an unambiguous description, we formally specify our SA-ARTIS-agent using Time-Communicating Object-Z (TCOZ) language. The objective of this research is to provide an intelligent agent with self-adaptive abilities for the execution of tasks with temporal constraints. Previous works in this domain have used Z language which is not expressive to model the distributed communication process of agents. The novelty of our work is that we specified the non-terminating behavior of agents using active class concept of TCOZ and expressed the distributed communication among agents. For communication between active entities, channel communication mechanism of TCOZ is utilized. We demonstrate the effectiveness of the proposed agent using a real-time case study of traffic monitoring system

Logic meets Probability: Towards Explainable AI Systems for Uncertain Worlds

Logical AI is concerned with formal languages to represent and reason with qualitative specifications; statistical AI is concerned with learning quantitative specifications from data. To combine the strengths of these two camps, there has been exciting recent progress on unifying logic and probability. We review the many guises for this union, while emphasizing the need for a formal language to represent a system's knowledge. Formal languages allow their internal properties to be robustly scrutinized, can be augmented by adding new knowledge, and are amenable to abstractions, all of which are vital to the design of intelligent systems that are explainable and interpretable.</jats:p

Implementing e-Services in Lagos State, Nigeria: the interplay of Cultural Perceptions and Working Practices during an automation initiative : Nigeria e-government culture and working practices

Accepted for publication in a forthcoming issue of Government Information Quarterly.The public sector’s adoption of Information and Communication Technologies is often seen as a way of increasing efficiency. However, developing public e-Services involves a series of organisational and social complexities. In this paper, we examine the organisational issues of implementing an ERP system, which was designed and developed within the context of Lagos State’s e-Services project. By doing so, we showcase the impact of organisational cultural perceptions and working practices of individuals. Our findings illustrate the strong role of cultural dimensions, particularly those pertaining to religion and multi-ethnicity. Our study provides insights to international organisations and governments alike toward project policy formulation within the context of ICT-based initiatives and reforms that aim to bring forward developmental progress.Peer reviewedFinal Accepted Versio

Composing with Microsound: An Approach to Structure and Form when Composing for Acoustic Instruments with Electronics

This paper explores the implications of using microsound as an organising principle when structuring composition for acoustic instruments and electronics. The ideas are presented in the context of a composition by the author for bass clarinet, flute, piano and electronics: The Sea Turns Sand To Stone (2015). After giving a definition of microsound, the compositional affordances of microsound are considered. Microsound is presented as an aesthetically rich tool for creating cohesion between acoustic and electroacoustic sounds and different parameters for manipulating the sounds are presented. Issues of structure and form are discussed and the challenges of creating a coherent environment that uses both note-based and texture-based material are explored. The implications of applying different models of form to mixed compositions are considered. This leads to a discussion of the different relationships that exist between the acoustic and the electroacoustic parts of a composition. Extended instrumental techniques provide one way of creating perceptual links between the acoustic and the electroacoustic. Examples of the way such techniques have been used in conjunction with microsound to impose a structural framework on The Sea Turns Sand To Stone are given. Finally, the use of a pure sound/noise axis, mediated through the application of microsound, is presented as a viable organising principle for structuring mixed compositions. The implications of such a model are explored and the underlying structure of The Sea Turns Sand To Stone is presented as a practical example of the application of the process

Theory of Dispersed Fixed-Delay Interferometry for Radial Velocity Exoplanet Searches

The dispersed fixed-delay interferometer (DFDI) represents a new instrument concept for high-precision radial velocity (RV) surveys for extrasolar planets. A combination of Michelson interferometer and medium-resolution spectrograph, it has the potential for performing multi-object surveys, where most previous RV techniques have been limited to observing only one target at a time. Because of the large sample of extrasolar planets needed to better understand planetary formation, evolution, and prevalence, this new technique represents a logical next step in instrumentation for RV extrasolar planet searches, and has been proven with the single-object Exoplanet Tracker (ET) at Kitt Peak National Observatory, and the multi-object W. M. Keck/MARVELS Exoplanet Tracker at Apache Point Observatory. The development of the ET instruments has necessitated fleshing out a detailed understanding of the physical principles of the DFDI technique. Here we summarize the fundamental theoretical material needed to understand the technique and provide an overview of the physics underlying the instrument's working. We also derive some useful analytical formulae that can be used to estimate the level of various sources of error generic to the technique, such as photon shot noise when using a fiducial reference spectrum, contamination by secondary spectra (e.g., crowded sources, spectroscopic binaries, or moonlight contamination), residual interferometer comb, and reference cross-talk error. Following this, we show that the use of a traditional gas absorption fiducial reference with a DFDI can incur significant systematic errors that must be taken into account at the precision levels required to detect extrasolar planets.Comment: 58 pages, 11 figures, 1 table, 3 appendices. Accepted for publication in ApJS. Minor typographical corrections; update to acknowledgment

Automatic generation of descriptions for Prolog programs

It is often hard for students and newcomers used to imperative languages to learn a declarative language such as Prolog. One of their main difficulties is understanding the procedural component of Prolog. Despite being a declarative language, Prolog allows for the creation of procedures whose structure is very different from the more common imperative languages. To tackle this issue, we try to facilitate code comprehension of procedural Prolog through the generation of formal and natural descriptions. First, we represent the workflow of Prolog encoded procedures through formal descriptions similar to imperative languages. To do this, we identify programming patterns that represent the basic blocks of certain classes of Prolog programs. Then we view more complex Prolog programs as coherent compositions of instances of the basic patterns. By using formal templates, we formally describe these individual patterns into an intermediate formal language. Afterwards, we generate natural language descriptions by using templates to describe the formal constructs. Using this two-step approach, we obtain two descriptions (one formal and one in natural language) that are both explanatory of the original program.Normalmente é difícil para alunos e iniciantes que estão habituados a linguagens imperativas, aprender uma linguagem declarativa como o Prolog. Uma das suas principais dificuldades é entender a componente procedimental do Prolog. Apesar de ser uma linguagem declarativa, o Prolog permite a criação de procedimentos cuja estrutura é bastante diferente da usada nas linguagens imperativas. Para abordar este problema tentámos facilitar a compreensão de código do Prolog procedimental através da geração de descrições formais e em linguagem natural. Primeiro, representamos a lógica dos procedimentos em Prolog através de descrições formais similares a linguagens imperativas. Para isto, identificamos os padrões que representam os blocos básicos de certas classes de programas. Depois, consideramos os programas mais complexos como composições destes padrões básicos. Através da utilização de templates formais, descrevemos formalmente estes padrões individuais numa linguagem formal intermédia. Seguidamente, geramos descrições em linguagem natural utilizando templates para descrever os construtos formais. Ao usar esta abordagem de dois passos obtemos duas descrições (uma formal e uma em linguagem natural) que são ambas explanatórias do programa original