A Robust Dirichlet Reputation and Trust Evaluation of Nodes in Mobile Ad Hoc Networks

The distributed nature of mobile ad hoc networks (MANETs) presents security challenges and vulnerabilities which sometimes lead to several forms of attacks. To improve the security in MANETs, reputation and trust management systems (RTMS) have been developed to mitigate some attacks and threats arising from abnormal behaviours of nodes in networks. Generally, most reputation and trust systems in MANETs focus mainly on penalising uncooperative network nodes. It is a known fact that nodes in MANETs have limited energy resources and as such, the continuous collaboration of cooperative nodes will lead to energy exhaustion. This paper develops and evaluates a robust Dirichlet reputation and trust management system which measures and models the reputation and trust of nodes in the network, and it incorporates candour into the mode of operations of the RTMS without undermining network security. The proposed RTMS employs Dirichlet probability distribution in modelling the individual reputation of nodes and the trust of each node is computed based on the node’s actual network performance and the accuracy of the second-hand reputations it gives about other nodes. The paper also presents a novel candour two-dimensional trustworthiness evaluation technique that categorises the behaviours of nodes based on their evaluated total reputation and trust values. The evaluation and analyses of some of the simulated behaviours of nodes in the deployed MANETs show that the candour two-dimensional trustworthiness evaluation technique is an effective technique that encourages and caters to nodes that continuously contribute to the network despite the reduction in their energy levels.

Lubricant Evaluation Technique for Single Point Incremental Forming Process

Single-point Incremental Forming (SPIF) is highly flexible dieless forming process suitable for a small batch production. The higher the feed rate and tool rotational speed, the higher the production rate will be. Therefore, the selection of the suitable lubricant is a key important factor to maintain the formability of the material when increasing the feed rate and tool rotational speed. This paper proposes the technique to evaluate and later on select the proper lubricant for these conditions. This technique was divided into two phases; 1) screening, and 2) stabilization. The screening phase is a quick method for preliminary selection of the lubricants. The stabilizing phase is a step to evaluate reliability as well as ensure efficiency of the lubricant throughout the process, because of the significant increase of the forming temperature which affects directly to the performance of the lubricant. Two types of lubricants, namely solid (Graphite) and liquid (Callington Calform NF-206) lubricants mixed with the base oil (coconut oil) at different ratios were tested. The cold rolled hot-dipped zinc-coated steel sheet with thickness of 0.176 mm. and wall angles of 45, 50, 55 and 60 degrees with the depth of each wall angle of 5 mm were used. During the screening phase, the fifteen mixtures firstly were tested by using the achieved maximum wall angles without fracture as a criterion. Later on, the lubricant mixtures which could successfully form at the wall angle of 60 degrees with the forming depth of 20 mm would be tested in the stabilization phase to evaluate the formability and the forming temperature. The results showed that during the screening phase 11 lubricants could perform successfully, while the stabilization phase with the wall angle of 60 degrees only 3 lubricants could successfully form the workpiece. Therefore, this evaluation technique could help to evaluate and, for later on, be a criterion to select the select lubricant.

EMBEDDED REMOTE GROUP ENVIRONMENT THROUGH MODIFICATION IN MACBETH – AN APPLICATION OF CONTRACTOR’S SELECTION IN CONSTRUCTION

A group decision environment has profound roots in MACBETH (Measuring Attractiveness by a Categorical Based Evaluation Technique) analysis which indeed has plentiful advantages; however, many researchers envisage the embedded group decision system as an impediment in actual implementation. The accessibility of explicit interaction of decision makers at a single platform in the form of embedded group decision environment is a great impediment to the researchers. Accordingly, this research aims to tailor a novel alternative system of dealing with the embedded group decision under a remote group decision environment via integrating MACBETH and Exploratory Factor Analysis. The study finds that an embedded remote group decision making system could serve as an alternative system of group decision making which has plentiful perks in group decision applications. This system could help researchers to carry out research without confusing in embedded group decision environment but including all decision-makers in the model. The implication of proposed system is not only limited to MACBETH; however, due to system’s versatility, a similar approach could be fruitful for other group-related environments involving collective decisions.

Understanding UX Better: A New Technique to Go beyond Emotion Assessment

User experience (UX) is a quality aspect that considers the emotions evoked by the system, extending the usability concept beyond effectiveness, efficiency, and satisfaction. Practitioners and researchers are aware of the importance of evaluating UX. Thus, UX evaluation is a growing field with diverse approaches. Despite various approaches, most of them produce a general indication of the experience as a result and do not seek to capture the problem that gave rise to the bad UX. This information makes it difficult to obtain relevant results to improve the application, making it challenging to identify what caused a negative user experience. To address this gap, we developed a UX evaluation technique called UX-Tips. This paper presents UX-Tips and reports two empirical studies performed in an academic and an industrial setting to evaluate it. Our results show that UX-Tips had good performance in terms of efficiency and effectiveness, making it possible to identify the causes that led to a negative user experience, and it was easy to use. In this sense, we present a new technique suitable for use in both academic and industrial settings, allowing UX evaluation and finding the problems that may lead to a negative experience.

Teaching Geoheritage Values: Implementation and Thematic Analysis Evaluation of a Synchronous Online Educational Approach

The purpose of this article is to present the results of an environmental education program on “Storm-Tossed Sea Rocks in Pelion Seaside” designed for junior high school students and implemented as a synchronous online educational approach and main and with a main goal to empower students to the values of geoheritage. In order to examine the effectiveness of the program and in particular the achievement of the objectives that encourage the development of values, the research question was identified as to whether the implementation of the environmental program achieved the empowerment of students in geoheritage values. In order to answer this question, we implemented a rather unusual technique to evaluate the educational procedure, which was based on the qualitative research technique of thematic analysis. This technique was selected as the most appropriate in order to “mine” conceptual patterns, the analysis of which would, in a valid, reliable, and simultaneously easy to use and quick way, inform the teachers that the values of geoheritage were disseminated to the students through the program. Thus, four-question interviews were conducted with randomly selected students who participated in the program. The data were examined and conceptual patterns were identified which were classified in eighteen codes. The codes were divided into five categories, the analysis of which led to the answer to the research question. Thus, it was found that the implementation of the environmental program achieved the empowerment of students in geocultural heritage values. The development of feelings of environmental sensitivity has also been seen, which suggests further investigation is needed. It was concluded that for the students, the given educational approach was necessary as well as cognitively, pedagogically, and emotionally beneficial; therefore, the need to enrich the curricula of environmental education/education for sustainable development with issues of geodiversity and geocultural heritage is justified. Finally, what was ascertained is that the thematic-analysis-based evaluation technique of the educational procedure, which was implemented, provided the teachers with the requested information, and it is recommended as an evaluation technique of educational procedures which aim at empowering students on values—even for daily use in school.

Science Process Skills and Its Implementation in the Process of Science Learning Evaluation in Schools

The study aimed to find out the science process skills and its implementation in the process of science learning evaluation in the schools. The studied aspects in the study consisted of the nature of science process skills, types of science process skills, assessment techniques for science process skills, and the assessment implementation of science process skills in learning in the schools. The research used a literature study containing relevant theories and further elaborated and its implementation in science learning in the schools. The study emphasized that science process skills were closely related to science learning and prioritize the overall assessment following the nature of science, such as product, process, and attitude dimensions. Those were covered in basic and integrated process skills. The most possible evaluation technique in measuring the science process skills was by observation or performance and written questions following the indicators of science process skills.