Cost Computation Research Articles

Stability and Dispersion Analysis of a TLM Unified Approach for Dispersive Anisotropic Media

With the advancement of technology, modern equipment involves new functionalities that require complex media (e.g., anisotropic dispersive media such as ferrite, lossy dielectrics, or graphene) for a variety of applications. This imposes the necessity to extend simulation techniques capable of solving Maxwell’s equations in such media. However, as far as discrete time-domain models are concerned, their performance in terms of dispersion and stability criterion has not been thoroughly investigated in the presence of complex media. More particularly, a question arises about which maximum mesh size can be used and the resulting time step to ensure stability. Starting from a transmission-line matrix method algorithm for the general linear media, procedures for dispersion and stability analysis are given and special cases are presented. It is found that the proposed approach allows, in certain cases, some significant reduction in the computer cost compared to the approximate rules generally used. The same procedures can be easily extended to other time-domain schemes such as FDTD.

Minimal gain marching schemes: searching for unstable steady-states with unsteady solvers

Reference solutions are important in several applications. They are used as base states in linear stability analyses as well as initial conditions and reference states for sponge zones in numerical simulations, just to name a few examples. Their accuracy is also paramount in both fields, leading to more reliable analyses and efficient simulations, respectively. Hence, steady-states usually make the best reference solutions. Unfortunately, standard marching schemes utilized for accurate unsteady simulations almost never reach steady-states of unstable flows. Steady governing equations could be solved instead, by employing Newton-type methods often coupled with continuation techniques. However, such iterative approaches do require large computational resources and very good initial guesses to converge. These difficulties motivated the development of a technique known as selective frequency damping (SFD) (Akervik et al. in Phys Fluids 18(6):068102, 2006). It adds a source term to the unsteady governing equations that filters out the unstable frequencies, allowing a steady-state to be reached. This approach does not require a good initial condition and works well for self-excited flows, where a single nonzero excitation frequency is selected by either absolute or global instability mechanisms. On the other hand, it seems unable to damp stationary disturbances. Furthermore, flows with a broad unstable frequency spectrum might require the use of multiple filters, which delays convergence significantly. Both scenarios appear in convectively, absolutely or globally unstable flows. An alternative approach is proposed in the present paper. It modifies the coefficients of a marching scheme in such a way that makes the absolute value of its linear gain smaller than one within the required unstable frequency spectra, allowing the respective disturbance amplitudes to decay given enough time. These ideas are applied here to implicit multi-step schemes. A few chosen test cases shows that they enable convergence toward solutions that are unstable to stationary and oscillatory disturbances, with either a single or multiple frequency content. Finally, comparisons with SFD are also performed, showing significant reduction in computer cost for complex flows by using the implicit multi-step MGM schemes.

The Laguerre finite difference one-way equation solver

This paper presents a new finite difference algorithm for solving the 2D one-way wave equation with a preliminary approximation of a pseudo-differential operator by a system of partial differential equations. As opposed to the existing approaches, the integral Laguerre transform instead of Fourier transform is used. After carrying out the approximation of spatial variables it is possible to obtain systems of linear algebraic equations with better computing properties and to reduce computer costs for their solution. High accuracy of calculations is attained at the expense of employing finite difference approximations of higher accuracy order that are based on the dispersion-relationship-preserving method and the Richardson extrapolation in the downward continuation direction. The numerical experiments have verified that as compared to the spectral difference method based on Fourier transform, the new algorithm allows one to calculate wave fields with a higher degree of accuracy and a lower level of numerical noise and artifacts including those for non-smooth velocity models. In the context of solving the geophysical problem the post-stack migration for velocity models of the types Syncline and Sigsbee2A has been carried out. It is shown that the images obtained contain lesser noise and are considerably better focused as compared to those obtained by the known Fourier Finite Difference and Phase-Shift Plus Interpolation methods. There is an opinion that purely finite difference approaches do not allow carrying out the seismic migration procedure with sufficient accuracy, however the results obtained disprove this statement. For the supercomputer implementation it is proposed to use the parallel dichotomy algorithm when solving systems of linear algebraic equations with block-tridiagonal matrices.

Taking social media to a university classroom: teaching and learning using Twitter and blogs

Social media has taken many sectors including the higher education by storm. However, with wide spread fears that social media may be a distractor to pedagogy, this paper investigated how social media facilitates teaching and learning. Unlike most prior studies which relied much on soliciting mere views from students and lecturers about their intentions to use or not to use social media, this study incorporated Twitter and blogs into two undergraduate courses offered in the Department of Library and Information Science at Mzuzu University which is a public university in Malawi. Data were collected in two ways: first, analysis of blog and Twitter posts by students and second, a questionnaire was sent to 64 students to find out their perception towards the use of blogs and Twitter in a classroom environment. Results suggest that if appropriately deployed, Twitter and blogs are catalysts for the much hyped learner-centred approach to teaching because using these technologies, it emerged that students shared and discussed course materials, posted their course reflections and interacted amongst themselves and with their lecturer 24/7. Challenges faced include cost of internet data bundles, inaccessible Wi-Fi, poor bandwidths and insufficient computers.

Efficiency of Trigonometric and Eigen Function Methods for Simulating Ocean Wave Profile

The series representation of ocean wave surface elevation profile using an existing spectral energy density can be achieved by linear superposition of terms in an expansion. This study demonstrates that the use of Karhunen-Loeve (K-L) expansion in which the eigenfunctions of Prolate Spheroidal Wave Functions (PSWFs) are used can be correlated with Fourier and constrained new wave approach in terms of computer cost required (3.225x103s, 3.0615x103s and 1.3221x104s respectively) in the wave simulation (maximum difference of 0.007% and minimum of 0.077%). It have also been demonstrated that the use of K-L with PSWFs can significantly reduce the number of the terms required to represent the wave which can greatly reduce the computational effort required in the statistical analysis of response from large offshore structures.

The challenging facts of virtual reality technology

The Virtual Reality (VR) technology has been widely used in many areas such as gaming, scientific and military application from 1950s. With the computer technology development and cost reduction, the VR technology is also progressing from professional application to consumer level. The year 2016 is under the consensus of the year of VR. In this paper, the current VR technologies are analyzed from the industry and consumer point of view based on the fundamental concepts. The technical status of current consumer level VR is reviewed with respect to the challenging facts.

Benefits and challenges of cloud ERP systems – A systematic literature review

Enterprise Resource Planning (ERP) systems provide extensive benefits and facilities to the whole enterprise. ERP systems help the enterprise to share and transfer data and information across all functions units inside and outside the enterprise. Sharing data and information between enterprise departments helps in many aspects and aims to achieve different objectives. Cloud computing is a computing model which takes place over the internet and provides scalability, reliability, availability and low cost of computer reassures. Implementing and running ERP systems over the cloud offers great advantages and benefits, in spite of its many difficulties and challenges. In this paper, we follow the Systematic Literature Review (SLR) research method to explore the benefits and challenges of implementing ERP systems over a cloud environment.

An Embedded System for applying High Performance Computing in Educational Learning Activity

HPC (High Performance Computing) has become more popular in the last few years. With the benefits on high computational power, HPC has impact on industry, scientific research and educational activities. Implementing HPC as a curriculum in universities could be consuming a lot of resources because well-known HPC system are using Personal Computer or Server. By using PC as the practical moduls it is need great resources and spaces. This paper presents an innovative high performance computing cluster system to support education learning activities in HPC course with small size, low cost, and yet powerful enough. In recent years, High Performance computing usually implanted in cluster computing and require high specification computer and expensive cost. It is not efficient applying High Performance Computing in Educational research activiry such as learning in Class. Therefore, our proposed system is created with inexpensive component by using Embedded System to make High Performance Computing applicable for leaning in the class. Students involved in the construction of embedded system, built clusters from basic embedded and network components, do benchmark performance, and implement simple parallel case using the cluster. In this research we performed evaluation of embedded systems comparing with i5 PC, the results of our embedded system performance of NAS benchmark are similar with i5 PCs. We also conducted surveys about student learning satisfaction that with embedded system students are able to learn about HPC from building the system until making an application that use HPC system.

Integrating Technology Into Instruction At A Public University In Kyrgyzstan: Barriers And Enablers

Background:The purpose of this study was to determine enablers and barriers to the technology integration into education based on the example of the situation at the Kyrgyz-Turkish Manas University as reported by students and instructors.Material and methods:The study employed the mixed-methods research design, combining data obtained from 477 student and 57 instructor questionnaires supplemented by interviews with 11 students and 9 instructors.Results:The study revealed that although technology is being used at the universities all over the country, there still exists the lack of both hardware and software laboratories and the instructors have limited knowledge and experience with technology, which, in its turn, indicates the shortage of qualified technical personnel. The cost of personal computers and problems with the Internet connection were claimed to be the major barriers for students.Conclusions:The results of this study can be used by the Kyrgyz-Turkish Manas University, the Ministry of Education, and by other related institutions in Kyrgyzstan. Furthermore, the results can contribute to the existing literature on the use of ICT in the country.

Editorial

Just a little bit more than three decades has passed since IBM introduced the personal computer (PC), and this technology started to be introduced easier into the daily life of different kind of companies. With the subsequent reduction of the computer costs during the nineties and the first decade of the current century, more and more people were able to afford a PC, and computers became one of our most important belongings. Parallel to this growth of the computer industry, the field of knowledge concerning the development of computer programs, which are actually the part that let us interact with, and extract the potential of the computers, has had perhaps, one of the fastest growing in history. Computing addresses the design of hardware and software systems for many different purposes including processing, structuring, and managing various types of information, and encompasses several subareas such as computer engineering, computer science, information systems, information technology and software engineering, each of which has its own interests and challenges.

EMPOWERMENT DIGITAL DIVIDE: CASE OF INTERNET ADOPTION IN UGANDA’S RURAL - URBAN AREAS

Over the years the concept of digital divide has shifted from having to do with those who have access to technology and those who don't because technology has become more mobile. There is wide increase in computer access in schools and personal ownership, slight decrease in computer costs, increase in internet access and wide spread access to mobile phones and services. It is no longer an issue of lack of access but being empowered to optimally use the technology or internet. Taking a rural-urban stride in Uganda‟s use of Internet, it is revealed that a regional imbalance still exists. Urban dwellers are highly empowered to use internet compared to rural dwellers as this paper will reveal. This paper therefore sets out to explore the empowerment of rural-urban dwellers to adopt Internet as an innovation taking a case of Uganda. Methodology: Quantitative and qualitative approaches were used to accomplish the study. Interview guides and questionnaires were used to collect qualitative and quantitative data respectively from internet café owners and users. Findings: Findings suggest that relative advantage, complexity, compatibility as well as trialbility being strong predictors of internet adoption. Relative advantage of the internet was found to be the strongest predictor of internet adoption in the rural urban areas. The concept of empowerment of users was found lacking and that explained the low scores on the trialbility concept.

Measuring costs of data collection at village clinics by village doctors for a syndromic surveillance system-a cross sectional survey from China.

BackgroundStudies into the costs of syndromic surveillance systems are rare, especially for estimating the direct costs involved in implementing and maintaining these systems. An Integrated Surveillance System in rural China (ISSC project), with the aim of providing an early warning system for outbreaks, was implemented; village clinics were the main surveillance units. Village doctors expressed their willingness to join in the surveillance if a proper subsidy was provided. This study aims to measure the costs of data collection by village clinics to provide a reference regarding the subsidy level required for village clinics to participate in data collection.MethodsWe conducted a cross-sectional survey with a village clinic questionnaire and a staff questionnaire using a purposive sampling strategy. We tracked reported events using the ISSC internal database. Cost data included staff time, and the annual depreciation and opportunity costs of computers. We measured the village doctors’ time costs for data collection by multiplying the number of full time employment equivalents devoted to the surveillance by the village doctors’ annual salaries and benefits, which equaled their net incomes. We estimated the depreciation and opportunity costs of computers by calculating the equivalent annual computer cost and then allocating this to the surveillance based on the percentage usage.ResultsThe estimated total annual cost of collecting data was 1,423 Chinese Renminbi (RMB) in 2012 (P25 = 857, P75 = 3284), including 1,250 RMB (P25 = 656, P75 = 3000) staff time costs and 134 RMB (P25 = 101, P75 = 335) depreciation and opportunity costs of computers.ConclusionsThe total costs of collecting data from the village clinics for the syndromic surveillance system was calculated to be low compared with the individual net income in County A.

Finite Element Analysis of a Bending Moment Formulation for the Vibration Problem of a Non-homogeneous Timoshenko Beam

In this paper we analyze a low-order finite element method for approximating the vibration frequencies and modes of a non-homogeneous Timoshenko beam. We consider a formulation in which the bending moment is introduced as an additional unknown. Optimal order error estimates are proved for displacements, rotations, shear stress and bending moment of the vibration modes, as well as a double order of convergence for the vibration frequencies. These estimates are independent of the beam thickness, which leads to the conclusion that the method is locking free. For its implementation, displacements and rotations can be eliminated leading to a well posed generalized matrix eigenvalue problem for which the computer cost of its solution is similar to that of other classical formulations. We report numerical experiments which allow us to assess the performance of the method.

Mathematical Tools and Approaches for Polymerization Reaction Engineering II— Statistical Modeling Tools and Approaches

Mathematical Tools and Approaches for Polymerization Reaction Engineering II— Statistical Modeling Tools and Approaches

Staying safe in the community: adaptation of WaySafe to help probationers make better decisions about their health risks

Transition from incarceration to the community is a critical time for offenders, especially those with substance abuse problems. Many succumb to temptation to return to drug use and possibly risky needle sharing, and engaging in risky sex activities. This critical time period entails substantial health risks for the offender as well as significant risks to public health. Well-established and consistent use of HIV/HBV/HCV risk reduction prevention programs with continuity of care do not exist in most criminal justice treatment systems because of lack of policy development and integration between institution and community-based corrections, health, and social service agencies. Interventions targeting re-entry are crucial because of the likelihood for risk behaviors to increase upon return to the community. Approaches for community correction populations are needed that have the capability of addressing motivational, social, and cognitive deficits. This presentation discusses an approach to translating ideas from the prison-based WaySafe curriculum into community settings for probationers who have recently completed residential, intensive outpatient, or prison-based substance abuse treatment. The adapted intervention, StaySafe, will be based on evidence-based cognitive principles, including TCU Mapping Enhanced Counseling techniques designed to improve decision-making skills regarding health risk behaviors during the critical first 6 months under community supervision. It is being designed to be self-administered by participating probationers during downtime, either prior to or following meetings with their probation officers. An important goal in the adaptation and testing of StaySafe is to have a sustainable, evidence-based product for probation departments that can be administered with minimal staff training and time that is engaging and easy to use by probationers, requires minimal maintenance, and is free to probation departments (other than the cost of the touch-screen computers). In this presentation, we describe the StaySafe intervention and the adaptation process from a prison-based group curriculum to a community corrections-based individualized approach. The adaptation process borrows ideas from the ADAPT-ITT framework [1]. We will describe initial results from focus groups and interviews with probationers and probation officers on problems and successes in probation, logistical issues with delivering interventions in probation settings, and results of a “theater” test of elements of StaySafe to gauge participant reactions.

Research on Linux-Based PC Cluster System and its Application in Numerical Simulation for Shallow Buried Soft Soil Tunnel

Since numerical simulation method came out, it has caused a great importance to tunnel engineers and has been used widely. But it has been restricted in three-dimensional numerical analysis of multi-element and multi-working conditions because the out of memory of personal computer, the high cost of high-performance computer and so on. In view of this, we need to search the low-cost computing devices to solve the large-scale three-dimensional numerical simulation in tunnel engineering. After investigation and study, we have built a Linux-based PC cluster system successfully, and use it to simulate the excavation process of Xiamen Jiaheyuan underground access which is a rectangular shallow buried soft soil tunnel. The simulation results provide a basis for the construction. Linux-based PC cluster system provides a convenient and cheap solution for tunnel engineers in three-dimensional numerical simulation of multi-element and multi-working conditions.

Extension of the Reduced Integration Scheme to Calculate the Direct Exchange Areas in 3D Rectangular Enclosures with Nonscattering Media

The evaluation of direct exchange areas (DEA) in zonal method is the most important task due to the heavy computer cost of multi-integrals together with the existing of singularities. A technique of variable transformation to reduce the fold of integrals, which was developed originally by Erkku (1959) to calculate the DEAs of uniformly zonal dividing cylindrical system, was extended by Tian and Chiu (2003) for nonuniformly zonal dividing cylindrical system with large thermal gradients. In this paper, we further extend the reduced integration scheme (RIS) to calculate the DEAs in three-dimensional rectangular system. The detail deductions of six-, five-, and fourfold integrals to threefold ones are presented; the DEAs in a rectangular system with assumption of gray medium are computed by the Gaussian quadrature integration (GQI) and the RIS comparatively. The comparisons reveal that the RIS can provide remarkable higher accuracy and efficiency than GQI. More interestingly and practicably, the singularities of DEAs can be decomposed and weakened obviously by RIS.

A study on the 0D phenomenological model for diesel engine simulation: Application to combustion of Neem methyl esther biodiesel

The design and monitoring of modern diesel engines running on alternative fuels require reliable models that can validly substitute experimental tests and predict their operating characteristics under different load conditions. Although there exists a multitude of models for diesel engines, 0D phenomenological models present the advantages of giving fast and accurate computed results. These models are useful for predicting fuel spray characteristics and instantaneous gas state. However, there are few reported studies on the application of 0D phenomenological models on biodiesel fuel combustion in diesel engines.This work reports the elaboration, validation and application on Neem methyl ester biodiesel (NMEB) combustion of a 0D phenomenological model for diesel engine simulation.The model addresses some specific aspects of diesel engine modeling found in previous studies such as the compromise between computers cost, accurateness and model simplicity, the reduction of the number of empirical fitting constant, the prediction of combustion kinetics with reduction of the need of experimental curve fitting, the ability to simultaneously predict under various loads engine thermodynamic and spray parameters as well as emission characteristics and finally the ability to simulate diesel engine parameters when fueled by alternative fuels.The proposed model predicts fuel spray behavior, in cylinder combustion and nitric oxides (NOx) emissions. The model is implemented through a Matlab code. The model is mainly based on Razlejtsev’s spray evaporation model, Watson’s double Wiebe function and Ferguson’s tabulated chemistry thermodynamic cycle algorithm. NOx emissions are implemented in the model using the extended Zeldovich mechanism, heat transfer and ignition delay are also taken into account in the model.Following the validation in different operating points of the model on a four stroke 1 – cylinder direct injection diesel engine, the operating characteristics were predicted with an average error accuracy of about 15%. The relative error is, respectively, 10% for Sauter diameter, 12% for maximum penetration, 9.8% for peak pressure, 7.38% for peak temperature, 10.7% for NOx emission and 13.7% for engine power output. The model predicts higher Sauter mean diameter, higher fuel spray length and NOx emission for NMEB as compared to conventional diesel fuel which is in accordance with experimental results obtained on biodiesel fuels in previous researches. Methyl butyrate and methyl butanoate thermochemical data were used as surrogates for NMEB, the results obtained from the model were close, independently of the surrogate used for biodiesel. The average simulation time for a full cycle simulation was about 94.22s, which gives to the model applicability for diesel engine optimization purposes. The results obtained were found satisfactory in terms of accuracy, algorithm simplicity and computer cost.

Something New: A Scholarly Review and Clinical Perspective of Black Online Dating

For many busy and transient Black professionals, online dating may seem like a viable social option yet qualitative inquiry in a clinical setting revealed apprehensiveness to meeting potential partners on the internet. Perceived personal barriers included an interest in dating others who were similar (e.g., homogamy) in class, race, and/or religion. An exploration of quantitative research findings supports the broad existence of these perspectives among some Black professionals. Economic considerations, such as the cost of computers and online dating memberships, are also outlined as potential barriers. Additionally, soft research techniques (e.g., internet search results describing a topic subjectively, culturally, or opinion-based) were implored to fill the gap left by the limited hard research on the process of online dating, the challenges associated with its use (e.g., discrimination, digital deception), and the cultural norm differences in face-to-face versus online dating. Research on online dating is growing but minimal attention has been given to the experiences of Blacks who might be increasingly utilizing these social networking tools. The present paper examines these perceptions in the context of the sparse literature on Black online dating. Implications for future research and recommendations for Black online daters are provided.

WE-G-16A-01: Evolution of Radiation Treatment Planning

WE-G-16A-01: Evolution of Radiation Treatment Planning