Solving Quadratic Assignment Problem with Fixed Assignment (QAPFA) using branch and bound approach

Quadratic Assignment Problem (QAP) has been a very popular problem to be solved among researchers due to its practical applications. Several variants of QAP have been proposed by researchers in the past in order to reflect the real situations of QAP. One of the real problems of QAP is related with facilities which are required to be assigned to certain locations due to its function. In solving this problem, a fixed assignment has to be made thus allowing for the complexity of the problem to be reduced. Hence, this study introduces Quadratic Assignment Problem with Fixed Assignment (QAPFA) with the objective to minimize the assignment cost between the facility and location. This assignment takes into account the flow and distance between facility and location. QAPFA represents the real-world situation of the problem especially in dealing with specific requirement of some facilities to specific locations. Dataset of QAPFA is introduced and is solved using branch and bound approach. As for validation, the results of QAPFA are compared with QAP in terms of objective function and running time. The computational results show that the solution quality of QAPFA is lower when compared with the QAP, while the running time for QAPFA is lower than the QAP. Since the complexity of the problem is reduced by fixing the assignment, thus there is possibility that QAPFA has lower quality than QAP due to the fixed assignment. Nevertheless, in terms of running time QAPFA is better than QAP. It can be concluded that this problem reflect the real problem and practical to be used

The Impact of Virtual Nature Therapy on Stress Responses: A Systematic Qualitative Review

This study aims to review the key findings of past studies that assessed the impact of virtual environments, such as nature and forests for stress therapy. Previous research has found that virtual reality (VR) experiences affect socio-affective behavior, indicating the potential of using VR for cognitive and psychological stress therapy. However, evidence for the impacts of virtual forest therapy as a stress-reduction technique is lacking, and the usefulness of these techniques has yet to be determined. This review was carried out following the preferred reporting items for meta-analyses and systematic reviews. It summarized the literature and provided evidence on virtual forest therapy (VFT) effectiveness in stress relief. We conducted a literature search considering VR-related studies published from 2013 until June 2021 for different databases, including Embase, Medline/PubMed, Hindawi, ScienceDirect, Scopus, Web of Science, Taylor & Francis, and the Cochrane Library, to see how effective VFT reduces stress levels and improves mental well-being. According to the set inclusion criteria, eighteen relevant papers detailing original research were eligible for inclusion. This overview suggests that VR provides benefits for assessing and reducing stress levels. While real natural environments effectively promote recovery from stress, virtual exposure to nature also positively affects stress. Thus, VR could be an effective technique for promoting relaxation, particularly during the COVID-19 pandemic, where stress levels rise globally. However, more in-depth studies are required to substantiate this potential field of VR relaxation

A nonlinear heuristic modifier for constructing examination timetable

This research focuses on solving an examination timetabling problem by constructing solution using nonlinear heuristic modifier of Graph Coloring Heuristics.Two graph coloring heuristics i.e. largest degree and saturation degree were used within the nonlinear heuristic modifier to generate difficulty value of each examination, where it was modified non linearly whenever an examination cannot be scheduled in the previous iteration. Next, new ordering of examinations was obtained based on the new difficulty values and each examination was scheduled until a complete timetable is obtained. The nonlinear heuristic modifier is proposed to set a difficulty value of an examination within a nonlinear range, so that an effective estimation of examination’s difficulty could be obtained. The Toronto benchmark datasets were used in the experiment where the aim is to obtain an examination schedule with minimum penalty value. It is found that the proposed method is comparable with other approaches, hence gives better examination ordering

Sub-group quadratic assignment problem: A variant Of quadratic assignment problem with model development and comparison

Numerous research on Quadratic Assignment Problem (QAP) and its variants have been proposed in the past to reflect real-world problems. One of the real problems related to QAP is facilities are required to be assigned to certain locations due to their purposes. A set of assignment has to be made accordingly based on their requirements and allow complexities of the problem to be reduced. Hence, this study introduces a variant of QAP which is called as Sub-Group QAP (SGQAP) with the objective to minimize the assignment cost by taking into consideration the flow and distance between the facilities and locations. SGQAP represents real-world problem, especially in dealing with specific requirements of some facilities to a specific set of locations. In this study, mathematical model of the problem is developed and a data set of SGQAP with various sizes of group is introduced and solved. The results of SGQAP are compared with QAP and QAP with Fixed Assignment (QAPFA) in terms of objective function and running time in order to show variation in the solution quality when different condition is applied. The computational results show that the solution quality of SGQAP is better than QAPFA but not for QAP since the complexity was reduced by grouping facilities into a set of assignment. This isdue to the need to fulfill some preferences in the assignment which contribute to assignment cost. SGQAP is a new variant of QAP which is related to group assignment based on preferences, hence it contributes as a new practical problem which gives more flexibility and effectiveness in the assignment while maximizing the preferences

The Impact of Virtual Nature Therapy on Stress Responses: A Systematic Qualitative Review

This study aims to review the key findings of past studies that assessed the impact of virtual environments, such as nature and forests for stress therapy. Previous research has found that virtual reality (VR) experiences affect socio-affective behavior, indicating the potential of using VR for cognitive and psychological stress therapy. However, evidence for the impacts of virtual forest therapy as a stress-reduction technique is lacking, and the usefulness of these techniques has yet to be determined. This review was carried out following the preferred reporting items for meta-analyses and systematic reviews. It summarized the literature and provided evidence on virtual forest therapy (VFT) effectiveness in stress relief. We conducted a literature search considering VR-related studies published from 2013 until June 2021 for different databases, including Embase, Medline/PubMed, Hindawi, ScienceDirect, Scopus, Web of Science, Taylor & Francis, and the Cochrane Library, to see how effective VFT reduces stress levels and improves mental well-being. According to the set inclusion criteria, eighteen relevant papers detailing original research were eligible for inclusion. This overview suggests that VR provides benefits for assessing and reducing stress levels. While real natural environments effectively promote recovery from stress, virtual exposure to nature also positively affects stress. Thus, VR could be an effective technique for promoting relaxation, particularly during the COVID-19 pandemic, where stress levels rise globally. However, more in-depth studies are required to substantiate this potential field of VR relaxation.This research is supported by the Institute of Health Analytics (IHA), Universiti Teknologi PETRONAS