Different Kinds Of Models Research Articles

What good are abstract and what-if models? Lessons from the Gaïa hypothesis.

This article on the epistemology of computational models stems from an analysis of the Gaïa hypothesis (GH). It begins with James Kirchner's criticisms of the central computational model of GH: Daisyworld. Among other things, the model has been criticized for being too abstract, describing fictional entities (fictive daisies on an imaginary planet) and trying to answer counterfactual (what-if) questions (how would a planet look like if life had no influence on it?). For these reasons the model has been considered not testable and therefore not legitimate in science, and in any case not very interesting since it explores non actual issues. This criticism implicitly assumes that science should only be involved in the making of models that are "actual" (by opposition to what-if) and "specific" (by opposition to abstract). I challenge both of these criticisms in this article. First by showing that although the testability-understood as the comparison of model output with empirical data-is an important procedure for explanatory models, there are plenty of models that are not testable. The fact that these are not testable (in this restricted sense) has nothing to do with their being "abstract" or "what-if" but with their being predictive models. Secondly, I argue that "abstract" and "what-if" models aim at (respectable) epistemic purposes distinct from those pursued by "actual and specific models". Abstract models are used to propose how-possibly explanation or to pursue theorizing. What-if models are used to attribute causal or explanatory power to a variable of interest. The fact that they aim at different epistemic goals entails that it may not be accurate to consider the choice between different kinds of model as a "strategy".

Models for the modern power grid

This article reviews different kinds of models for the electric power grid that can be used to understand the modern power system, the smart grid. From the physical network to abstract energy markets, we identify in the literature different aspects that co-determine the spatio-temporal multilayer dynamics of power system. We start our review by showing how the generation, transmission and distribution characteristics of the traditional power grids are already subject to complex behaviour appearing as a result of the the interplay between dynamics of the nodes and topology, namely synchronisation and cascade effects. When dealing with smart grids, the system complexity increases even more: on top of the physical network of power lines and controllable sources of electricity, the modernisation brings information networks, renewable intermittent generation, market liberalisation, prosumers, among other aspects. In this case, we forecast a dynamical co-evolution of the smart grid and other kind of networked systems that cannot be understood isolated. This review compiles recent results that model electric power grids as complex systems, going beyond pure technological aspects. From this perspective, we then indicate possible ways to incorporate the diverse co-evolving systems into the smart grid model using, for example, network theory and multi-agent simulation.

Science, performance and transformation: performance for a ‘scientific’ age?

The ‘two cultures’ of science and the arts/humanities are often considered at odds, but digital technology, and the broader implications of digital culture, provides a model for more productive forms of exchange and hybridity. This article applies theories of intercultural theatre practice to performance that works across this cultural divide to explore the types of interaction that take place. Following a historical discussion of the science/art divide, a three-fold model is proposed and explored through case studies including Djerassi and Laszlo's 2003 NO, Eduardo Kac's 1999 Genesis, Reckless Sleepers' 1996/2006 Schrödinger's Box, and John Barrow's 2002 Infinities. It is argued that science operates through the creation of mathematical models of aspects of the physical world, whilst art similarly constructs different kinds of models for understanding the social/cultural and occasionally physical world. Digital technology expands the modelling possibilities both directly, through simulation, virtual reality and integration into ‘live’ activities of augmented and intermedia performance, and through the transformative nature of digital culture.

FIVE STEPS TO RESPONSIBILITY

Responsibility has entered the academic discourse of logicians hardly more than few decades ago. I suggest a logical concept of responsibility which employs ideas both from a number of theories belonging to different branches of logic as well from other academic areas. As a comment to this concept, I suggest five steps narrative scenario in order to show how the logical dimension of responsibility emerges from diverse tendencies in logic and other sciences. Here are the five steps briefly stated: Step 1. Developing modal formalisms capable of evaluative analysis of situations (deontic, epistemic and etc.). Step 2. Drawing a conceptual borderline between normal and non-normal (weak) logical systems. Step 3. Using different kinds of models. Step 4. Agentand actionfriendly turn in logic. Step 5. Creating formalisms for modeling different types of agency. An idea advocated here within 5-Steps route to responsibility is that this concept is a complex causal and evaluative (axiological) relation. A logical account may be given for causal and normative aspects of this relation. Unfolding the responsibility back and forth through 5 Steps will result in different concepts. The technicalities are minimized for the sake of keeping the philosophical scope of the paper. For the same reason I also refrain from discussing legal and juridical ramifications of the issue.

Software defined environments based on TOSCA in IBM cloud implementations

In recent years, the role of cloud computing in the information technology (IT) industry has been growing steadily, partly because IT developers are becoming empowered to provision, manage, and adjust IT resources through simple application programming interfaces. This enables the easy creation and manipulation of software defined environments consisting of server, storage, network, software, and the supporting management functions. Model-based deployment and management technologies that are based on upcoming standards such as the Topology and Orchestration Specification for Cloud Applications (TOSCA) of the Organization for the Advancement of Structured Information Standards (OASIS) allow for describing models of different kinds of workloads such as topology patterns and management plans. The term pattern refers to a description of components of a service, e.g., an application or infrastructure, and their relationships. This approach provides a flexible combination of declarative and imperative models of workloads that can be seamlessly integrated with automation frameworks such as Chef for task-level automation as well as management services to drive resource orchestration and optimization. In this paper, we explain how the aforementioned concepts are used as foundational elements of the software defined environment. We use an actual example motivated by a real customer scenario, and we explain the relation to the IBM Cloud Computing Reference Architecture and how it is applied within IBM cloud implementations.

URMG: Enhanced CBMG-based method for automatically testing web applications in the cloud

To satisfy the rapid growth of cloud technologies, a large number of web applications have been developed and deployed, and these applications are being run in clouds. Due to the scalability provided by clouds, a single web application may be concurrently visited by several millions or billions of users. Thus, the testing and performance evaluations of these applications are increasingly important. User model based evaluations can significantly reduce the manual work required, and can enable us to determine the performance of applications under real runtime environments. Hence, it has become one of the most popular evaluation methods in both industry and academia. Significant efforts have focused on building different kinds of models using mining web access logs, such as Markov models and Customer Behavior Model Graph (CBMG). This paper proposes a new kind of model, named the User Representation Model Graph (URMG), which is built based on CBMG. It uses an algorithm to refine CBMG and optimizes the evaluations execution process. Based on this model, an automatic testing and evaluation system for web applications is designed, implemented, and deployed in our test cloud, which is able to execute all of the analysis and testing operations using only web access logs. In our system, the error rate caused by random access to applications in the execution phase is also reduced, and the results show that the error rate of the evaluation that depends on URMG is 50% less than that which depends on CBMG.

Numerical Modeling and Simulation of Wind Blown Sand Morphology under Complex Wind-Flow Field

The flow field and the sand flow field constitutive equations are analyzed at first, then the different desert highway numerical models are established by considering the crossroad and by changing the road surface height and air stream flow field, then three kinds of different models with different complex air flow fields are made for simulating the sand ripple formation process by weak coupling of air and sand flow field, and finally the numerical simulations of these models are conducted and the affect process of sand morphology under complex air flow fields are discussed. The results show that under the uniform airflow field, the straight parallel ripple formed and the flared ripple formed in the middle region of the crossroad, and the wavelength of the ripples on the desert highway is bigger than that of the ripples around the road when the road height is higher than that of the sand surface height. Under the nonuniform complex airflow field, the complex curved ripples are formed, and some of the local area, where the whirlwind exits, no ripples are formed.

Multi-Scale Analyses and Combining Forecasts for Traffic Volumes

In view of that the current models are almost combining models of different kinds of forecast methods and the absence of substantial research on multi-scale combining in the context of traffic forecasts, we proposed a method that in multiple scales combines multiple forecasts based on prediction approaches of the same category. The method combines multi-scale analyses with exponential smoothing forecasting and its weights are assigned according to the performance of the various scales forecasts. Using four years actual data, we in two scales demonstrated it by forecasting annual traffic volumes for an expressway in China and the application verified its accuracy.

The Disassembly Process and Apparatus of Waste Printed Circuit Board Assembly for Reusing the Components

Printed Circuit Board Assembly (PCBA), is an important basic part of Electric and Electronic Equipment, which has lots of high-value components and toxic substances. Normally, when Electric and Electronic Equipment (EEE) is scraped, some components on waste PCBA still keep good performances. Therefore, it is feasible and economical to environment-friendly reuse the high-value components on waste PCBA. In order to guarantee the quality of the disassembled components, the components reuse-oriented disassembly process is proposed, in which the mechanical and physical characteristics of solder and the joint type of PCBA are considered comprehensively. In the process, through the analysis and measurement of the temperature distribution of PCBA, the optimized heating mode and heating temperature curve can be drawn up for the different joint type of PCBA. For getting the disassembly mode of PCBA, the disassembly force and separating displacement of components on PCBA are defined and the disassembly energy models for different kinds of components are set up. On the basis of the heating mode, heating temperature curve and disassembly energy, two kinds of disassembly apparatus and a performance testing procedure for certain kinds of old components are developed. In the end the components reuse-oriented disassembly process parameters are optimized to get a high separation ratio and reuse ration of components with orthogonal test.

Versioning and Evolution Control of Models in Software Configuration Management System

In this study we present an approach to address the issues of synchronization, evolution control and version granularity in Software Configuration Management (SCM). Our approach is based on a unified model developed during software lifecycle. The unified model consists of a set of different kinds of model and the interlinks information between these models, such models includes Analysis and design model, Test models etc. These models may possibly be created using different development tools in a heterogeneous environment. Our approach is based on identifying interlinks dependencies between different model elements. By using these interlinks information we develop our evolution control policy and perform synchronization of models elements.

Signature of strange dibaryons in kaon- and photon-induced reactions

We examine how the signature of the strange dibaryon resonances shows up in scattering amplitudes and observables of the three-body $\bar{K}NN$-$\pi Y N (Y=\Sigma, \Lambda)$ system on the physical real energy axis. The so-called point method is applied to handle logarithmic singularities that appear in solving the Alt-Grassberger-Sandhas equations for the real scattering energies. By taking two different kinds of models for the two-body $\bar{K}N$-$\pi \Sigma$ subsystem, both of which reproduce the available data equally well but give quite a different resonance-pole structure for $\Lambda(1405)$, we also investigate whether the strange-dibaryon production reactions can be used for disentangling the nature of $\Lambda(1405)$.

A Research on the Morphology and Composition of Flocs (Part 2: Floc Breakage Included)

The floc breakage plays an important role in the flocculation, the stable floc size or morphology distribution is the result of the equilibrium of formation and breakage. In this paper, the breakage approaches or models for different kind and size of flocs have been discussed. By introducing special breakage functions and comparing their relative values, the numbers of various flocs are verified to be still proportional to the suspension concentration compared with the situation in which the breakage is neglected. However, as illustrated in this paper, the total number of every kind of floc is still a power function of the suspension concentration for dilute suspensions where the number concentration of solid particles is linearly related to the volume concentration. This is similar to that where the breakage is disregarded, although the number for every kind of floc is inevitably changed. In addition, a potential quantitative method to analyze the relative composition of different kinds of flocs is presented by measuring the contributions of the flocs to the suspension viscosity.

Wireless Sensor Networks and the Internet of Things

It is estimated that mobile internet devices that can act as sensors will outnumber humans this year (2013), and by 2015, there will be about 15 billion internet-connected devices. Related applications are thriving in commercial, civic, and scientific operations that involve sensors, web, and services, leading by both academic societies and industry companies. It is commonly accepted that the next generation of internet is becoming the “Internet ofThings (IoT)”which is a worldwide network of interconnected objects and their virtual representations uniquely addressable based on standard communication protocols. Identified by a unique address, any object including computers, mobile phones, RFID tagged devices, and especially Wireless Sensor Networks (WSN) will be able to dynamically join the network, collaborate, and cooperate efficiently to achieve different tasks. With all these objects in the world equipped with tiny identifying devices, daily life on earth would undergo a big transformation. To achieve this vision, there is a need for scalable and interoperable networking systems to support the challenging requirements for future internet and web: secure, reliable, energy-efficient and cost-effective large-scale sensor networks, machine-to-machine communications, and information networking architectures suitable for low end devices through to high end consumers. The purpose of this special issue thus is to report on the recent and original advances on WSN and IoT that are to be innovative to open the new era of the Internet ofThings. From the many submissions we received, a number of exciting manuscripts stood out for their relevance and technical significance.These accepted papers touched upon threeWSN and IoT areas: IoT network infrastructure, related hardware design, and IoT protocols. A. Asensio et al. discussed the wireless sensor node architecture hardware design criterion based on energy analysis according to the specific requirements of an application. C. Liu et al. proposed a novelWSNauthentication scheme based on the quadratic residues theory, which uses themaster key to achieve simple symmetric cryptographic primitives and authentication operation for aims of great resistance against the attacks and low energy consumption. F. T. Lin proposed a method to tackle the dying nodes as well as the cost, specifically a holes healing scheme. C. Xu proposes a novel Vehicular Network-based CMT solution based on a CMT disorder analytic model which can effectively and accurately evaluate the degree of out-of-order data. S. Yin proposed two digital calibration and compensation techniques for low-power wireless multiband transceiver to adjust the VCO’s tuning curves in the frequency synthesizer and eliminate the DC offset voltage in the intermediate frequency pathway. J. Zhang proposed an energy-efficient distributed algorithm for virtual backbone construction with cellular structure WSN, which combines optimal coverage theory based on cellular structure and energy consumption model for different kinds of sensor nodes to achieve the construction and rotation of backbone in multiple rounds. By compiling these papers we hope to enrich our readers and researchers with latest innovative ideas with respect to the future Wireless Sensor Network and Internet of Things.

İlköğretim 7. ve 8. Sınıf Öğrencilerinin Gerçek-Yaşam Problemlerini Çözerken Sergiledikleri Yaklaşımlar ve Kullandıkları Strateji ve Modellerin İncelenmesi

AbstractThis study scrutinises approaches and thinking processes displayed by the elementary school students when solving real-world problems. It employed a qualitative inquiry to produce rich and realistic data about the case at hand. The research sample included 116 students. The data were obtained from written exam and semi-structured interviews, and they were analysed using content and discourse analysis methods. The results indicated that most of the students disregarded the real-life situations that the problems are related to. They displayed non-realistic approaches that included application of rules, procedures, and factual knowledge in a straightforward and uncritical way. Most of the students lacked the ability to use alternative approaches and appropriate strategies. Some constructed models of the problem situations, yet most of these students were not able to utilise these instruments as a conceptual tool to gain insight into the situations. Rather, models were used as part of the routine - rules, procedures and factual knowledge - that the students applied uncritically.Key WordsReal-World Problems, Problem Solving Approaches, Student Thinking, Problem Solving Strategies, Mathematical Models.Problem solving is considered the most significant cognitive activity in professional and everyday life (Jonassen, 2000). International documents suggest that problem solving should be used as an integrating theme in the mathematics curricula assuming that this could increase students' achievements in mathematics (Cockroft, 1982; National Council of Teachers of Mathematics [NCTM], 1989). It is indicated that students who followed problem-based mathematics curricula outperformed their counterparts both in mathematics achievement and in problem solving (Cai, 2003; Cai & Nie, 2007; Clarke, Breed, & Fraser, 2004). Problem refers to a situation in which the desired goal has to be attained but direct path towards the goal is blocked. It refers to a situation that requires resolution, but an individual sees no apparent path to the solution (Krulik & Rudnick, 1985; Orton & Wain, 1994). Briefly, if a situation causes cognitive conflicts in the minds of individuals it can be considered as a problem (Baki, 2006). Problem solving is a dynamic process in which students try to understand the situation, make a plan for the solution, select or develop methods and strategies, apply all these heuristics to get the solutions; and finally they check out the answers obtained (Barnet, Sowder, & Vos, 1980; Mayer, 1985; Polya, 1973; Schoenfeld, 1992; Suydam, 1980). In this process one may use various strategies (e.g., making a list, looking for patterns, working backwards) and different kinds of models (see Bayazit & Aksoy, 2008; Baykul, 2000; LeBlanc, 1977; Posamentier & Krulik, 1998). Mathematical problems are classified into two major categories: routine and non-routine problems. Routine problems can be resolved by the application of rules, procedures and basic operations that the problem solvers already know (Arslan & Altun, 2007; Mahlios, 1988). Non-routine problems causes great difficulties for students (Elia, Heuvel-Panhuizen, & Kolovou, 2009); this is because they do not have a straightforward solution; rather they request creative and critical thinking, employing alternative approaches and using various strategies and mathematical models (Altun, 2005; Inoue, 2005). In order to solve such problems one may need to use metacognitive skills including self-monitoring and self-regulations (Hartman, 1998; Mayer, Sims, & Tajika, 1995; Nancarrow, 2004).One type of non-routine problem includes real-world problems (Verschaffel, De Corte, & Vierstraete, 1999). Their solution requests giving particular attention to real-life contexts that the problems are related to. Students need to utilise their intuitive knowledge and daily-life experiences to resolve real-world problems (Nesher & Hershkovitz, 1997). …

Selecting fast-folding proteins by their rate of convergence

We propose a general method for predicting potentially good folders from a given number of amino acid sequences. Our approach is based on the calculation of the rate of convergence of each amino acid chain towards the native structure using only the very initial parts of the dynamical trajectories. It does not require any preliminary knowledge of the native state and can be applied to different kinds of models, including atomistic descriptions. We tested the method within both the lattice and off-lattice model frameworks and obtained several so far unknown good folders. The unbiased algorithm also allows one to determine the optimal folding temperature and takes at least 3-4 orders of magnitude fewer time steps than those needed to compute folding times.

An Energy-Efficient Distributed Algorithm for Virtual Backbone Construction with Cellular Structure in WSN

The construction of virtual backbone within wireless sensor network (WSN) is an important means to reduce the redundant transmission and conserve limited energy resources. However, if there is not a rotation scheme for the virtual backbone, the network lifetime is still considerably limited due to the quick exhaustion of the backbone nodes' energy. In this paper, we propose an Energy-efficient Distributed algorithm for virtual backbone construction with Cellular structure (EDBC) in WSN. The algorithm combines optimal coverage theory based on cellular structure and energy consumption model for different kinds of sensor nodes to achieve the construction and rotation of backbone in multiple rounds. The simulation results have shown that it improves the balance of energy consumption among sensor nodes and extends the network lifetime. It also provides good network stability as the number of backbone nodes selected in each round remains small and relatively constant.

Versatile Micromechanics Model for Multiscale Analysis of Composite Structures

A general-purpose micromechanics model was developed so that the model could be applied to various composite materials such as reinforced by particles, long fibers and short fibers as well as those containing micro voids. Additionally, the model can be used with hierarchical composite materials. The micromechanics model can be used to compute effective material properties like elastic moduli, shear moduli, Poisson’s ratios, and coefficients of thermal expansion for the various composite materials. The model can also calculate the strains and stresses at the constituent material level such as fibers, particles, and whiskers from the composite level stresses and strains. The model was implemented into ABAQUS using the UMAT option for multiscale analysis. An extensive set of examples are presented to demonstrate the reliability and accuracy of the developed micromechanics model for different kinds of composite materials. Another set of examples is provided to study the multiscale analysis of composite structures.

Longitudinal data: different approaches in the context of item-response theory models

In this paper, some extended Rasch models are analyzed in the presence of longitudinal measurements of a latent variable. Two main approaches, multidimensional and multilevel, are compared: we investigate the different information that can be obtained from the latent variable, and we give advice on the use of the different kinds of models. The multidimensional and multilevel approaches are illustrated with a simulation study and with a longitudinal study on the health-related quality of life in terminal cancer patients.

Smoke Control Models in Building Fire: A Literature Review

The smoke control is of great importance for the life safety of the occupants in the building fire. Many analytical models have been studied for the design of smoke control. The objective of the article is to bring several numerical simulation models about building fire and smoke movement. There are generally three kinds of different models, which are net model, zone model and field model. The characteristics and weak points of each category are discussed, indicating that each model might be applicable to different building fire scenarios.

A review of modeling approaches for sustainable supply chain management

More than 300 papers have been published in the last 15years on the topic of green or sustainable (forward) supply chains. Looking at the research methodologies employed, only 36 papers apply quantitative models. This is in contrast to, for example, the neighboring field of reverse or closed-loop supply chains where several reviews on respective quantitative models have already been provided. The paper summarizes research on quantitative models for forward supply chains and thereby contributes to the further substantiation of the field. While different kinds of models are applied, it is evident that the social side of sustainability is not taken into account. On the environmental side, life-cycle assessment based approaches and impact criteria clearly dominate. On the modeling side there are three dominant approaches: equilibrium models, multi-criteria decision making and analytical hierarchy process. There has been only limited empirical research so far. The paper ends with suggestions for future research.