Analysis and control of distributed systems using non-eigen space modes†

A method of analysing distributed systems with an arbitrary but suitably chosen set of space modes is presented. The method is most useful in situations where the eigenfunctions are not readily available and where the boundary conditions are control variables. The design of a feedback control is discussed along with the considerations of sensitivity and controllability.     

Analysis of remotely-sensed ecological indexes' influence on urban thermal environment dynamic using an integrated ecological index: a case study of Xi’an,China

The spatio-temporal pattern of surface ecological status affects urban thermal environment distribution significantly. Urban thermal pattern, however, is a complicated physical phenomenon involving a series of terrestrial environmental parameters. Thus, it is insufficient to employ only one ecological parameter for depicting the variation of land surface temperature (LST). This paper begins with the analysis of four ecological parameters' influence on LST using regression analysis, based on 24 Landsat images which cover Xi’an of China from 1992 to 2014. These four parameters include greenness degree (i.e. the soil adjusted vegetation index, SAVI), soil moisture degree (i.e. the normalized difference moisture index, NDMI), dryness degree (i.e. the normalized difference soil index, NDSI) and resident aggregation degree (i.e. the normalized difference build-up index, NDBI). Besides, contribution intensity index was introduced to investigate the contribution effect of four ecological parameters on LST, and a new ecological index, integrated ecological index (IEI), was founded using the principal component analysis technique to integratedly represent its spatial and mathematical correlations with LST. Results indicate that four ecological parameters all possessed pronounced performance in impacting LST pattern in all dates: SAVI and NDMI were found to be correlated negatively with LST, whereas NDBI and NDSI correlated positively with LST. Additionally, SAVI had a profound impact on LST distribution compared with the other three parameters, and there was the biggest heating contribution in the lowest SAVI category. Further finding suggests that IEI as a new ecological index can be used to integratedly estimate the spatio-temporal change of LST, manifesting a negative correlation with LST. Our study thinks that the comprehensive characterization of surface ecological status is conducive to benefit us to better understand the spatio-temporal mechanism of thermal environment and ecosystem and to help urban decision-makers to execute effective conservation policies for the ecosystem.     

Past and future of software architectural decisions – A systematic mapping study

ContextThe software architecture of a system is the result of a set of architectural decisions. The topic of architectural decisions in software engineering has received significant attention in recent years. However, no systematic overview exists on the state of research on architectural decisions.ObjectiveThe goal of this study is to provide a systematic overview of the state of research on architectural decisions. Such an overview helps researchers reflect on previous research and plan future research. Furthermore, such an overview helps practitioners understand the state of research, and how research results can help practitioners in their architectural decision-making.MethodWe conducted a systematic mapping study, covering studies published between January 2002 and January 2012. We defined six research questions. We queried six reference databases and obtained an initial result set of 28,895 papers. We followed a search and filtering process that resulted in 144 relevant papers.ResultsAfter classifying the 144 relevant papers for each research question, we found that current research focuses on documenting architectural decisions. We found that only several studies describe architectural decisions from the industry. We identified potential future research topics: domain-specific architectural decisions (such as mobile), achieving specific quality attributes (such as reliability or scalability), uncertainty in decision-making, and group architectural decisions. Regarding empirical evaluations of the papers, around half of the papers use systematic empirical evaluation approaches (such as surveys, or case studies). Still, few papers on architectural decisions use experiments.ConclusionOur study confirms the increasing interest in the topic of architectural decisions. This study helps the community reflect on the past ten years of research on architectural decisions. Researchers are offered a number of promising future research directions, while practitioners learn what existing papers offer.     

Formulation and study of thermal–mechanical coupling for saturated porous media

A formulation for the thermo-poro-elasto-plastic coupling analysis is presented, in which the energy balance equation is re-derived based on the concept of free enthalpy. The corresponding finite element procedures are developed and implemented into the commercial software ADINA. A complete solution strategy is described. The poro-mechanical and thermal coupling is conducted based on the simultaneous solution scheme for the isothermal poro-elasto-plastic interaction and the conventional thermal analysis. The complete solution procedures can be employed to solve both transient static and dynamic problems. The one-dimension column consolidation scenario is effectively re-examined with the proposed solution procedures, with heat and pore pressure dissipated on the top of the column. Accurate and reliable results with temperature and pore pressure distributions at different time steps are provided.     

Delineation and mapping of coal mine fire using remote sensing data – a review

Various countries around the globe face numerous hazards due to the burning of coal on the surface as well as below ground. Countries like China, India, United States of America (USA), Australia, Indonesia, and many other countries have reported the burning of coal fires, and thus it is the urgent need to control the coal fire propagation to prevent the loss of energy resources. Coal is a fossil fuel that has a tendency to catch fire for many reasons; spontaneous combustion being the most frequent reasons for its burning. Other factors leading to coal fire include forest fires close to coal seams, natural hazards, old mining techniques, and external heat sources. The review work demonstrates the application of various satellite data in fire detection and mapping. The literature reveals that remote sensing plays an important role in facilitating quick and complete delineation of coal mine fires. Many algorithms have been developed around the world for fire detection from different satellite data. A comprehensive demonstration of different algorithms along with their merits and demerits are outlined. Comparative performances of the different algorithms with their case studies are also explained. It can be inferred from the various literature that it is very difficult to select a particular sensor algorithm for generating global fire products. Suggestions are given to further explore the possibility of improvement of fire detection algorithms.     

Optimization of pin through hole connector in thermal fluid–structure interaction analysis of wave soldering process using response surface methodology

This paper presents an optimization of pin through hole (PTH) connector in the wave soldering process; the optimization was performed by using response surface methodology. The geometrical and process parameters (i.e., offset position, pin diameter, offset angle, and solder temperature) were optimized by using response surface methodology via central composite design for the wave soldering process. Thermal fluid–structure interaction aspects were considered in the optimization. A mesh-based parallel code-coupling interface was employed to connect both fluid and structural solvers. The interactive relationship between independent variables (i.e., offset position, pin diameter, offset angle, and solder temperature) and the responses (i.e., filling time at 75% volume, von Mises stress, and maximum displacement) were investigated. The generated empirical models were examined and well substantiated by the simulation results. The optimum geometrical and process parameters of the wave soldering process for the PCB and PTH connector were as follows: 0.12 mm of PTH offset position, 0.17 mm of PTH diameter, 0° of offset angle, and 473 K of molten solder temperature.     

Optimization of extrusion blow molding processes using soft computing and Taguchi’s method

The objective of this study is to present a new numerical strategy using soft-computing techniques to determine the optimal die gap programming of extrusion blow molding processes. In this study, the design objective is to target a uniform part thickness after parison inflation by manipulating the parison die gap openings over time. To model the whole process, that is, the parison extrusion, the mould clamping and the parison inflation, commercial finite element software (BlowSim) from the National Research Council (NRC) of Canada is used. However, the use of such software is time-consuming and one important issue in a design environment is to minimize the number of simulations to get the optimal operating conditions. To do so, we proposed a new strategy called fuzzy neural–Taguchi network with genetic algorithm (FUNTGA) that establishes a back propagation network using a Taguchis experimental array to predict the relationship between design variables and responses. Genetic algorithm (GA) is then applied to search for the optimum design of die gap parison programming. As the number of training samples is greatly reduced due to the use of orthogonal arrays, the prediction accuracy of the neural network model is closely related to the distance between sampling points and the evolved designs. The extrapolation distance concept is proposed and introduced to GA using fuzzy rules to modify the fitness function and thus improving search efficiency. The comparison of the results with commercial optimization software from NRC demonstrates the effectiveness of the proposed approach.     

Satellite thermal survey—a new tool for the study of seismoactive regions

The National Oceanic and Atmospheric Administration (NOAA)series satellite thermal images (STI) study showed the presence of positive anomalies of the outgoing Earth radiation flux recorded at night time and associated with largest linear structures and fault systems of the crust. The analysis of a continuous series (100-250 days) of nightly STI data for a period of 10 years allowed identification of a set of IR radiation anomalies in the Central Asian seismoactive region, Iran, Egypt, etc. About 10 000 NOAA images were analysed. It was actually discovered that there was a statistically significant correlation between the activity of IR anomalies (mean value of area per year or month) and the seismic activation of the Central Asian seismoactive region. At present the nature of stable and non-stable IR anomalies is not clear. In all probability hydrogeological factors or the greenhouse effect play a main role in forming the anomalies. Thus, satellite thermal survey is a tool for investigations of seismoactive regions and for earthquake predictions.     

Optimization of chemotherapy and immunotherapy: In silico analysis using pharmacokinetic–pharmacodynamic and tumor growth models

Chemotherapy is one of the most prominent cancer treatment modalities. However, it is not always a comprehensive solution for tumor regression. This led to the advent of novel strategies to combine chemotherapy with other emerging therapies to treat cancer patients keeping side effects to a minimum. In this work, the focus is on the optimization of chemotherapy using doxorubicin and its combination with adoptive-cell-transfer therapy which is one of the schemes of immunotherapy. The key challenge in the combination therapy is to find the sequence, timing and the dosage of therapies for a given patient. In this regard, an in silico pharmacokinetic/pharmacodynamic model describing the interaction between tumor cells, immune cells and doxorubicin is used to formulate a multi-objective optimization problem by considering clinically relevant objectives and constraints. Then, the multi-objective optimization problem is solved using genetic algorithm and the results obtained for the different cases are compared to discover a therapeutically efficacious treatment regimen. And the metrics used to compare different cases are final tumor size and tumor relapse time. The comparison between chemotherapy alone and its combination with immunotherapy shows that combination therapy is effective in controlling the tumor growth.     

Supporting rescheduling using CSP, RMS and POB—an example application

This paper introduces an innovative approach to the problem of rescheduling within manufacturing industry. An example of a manufacturing context that requires rescheduling capability is given (tyre production). The meaning of rescheduling, possible metrics for assessment of rescheduling and the advantages of applying the new techniques are reviewed. Of particular importance is the notion that the technology for providing rescheduling and explanation capabilities is to a large degree problem and context insensitive. The manner in which an original schedule has been created is irrelevant to the use of the technology described, allowing the advantages of the approach to be realized as an add-on facility to any existing scheduling system that fulfills a minimal set of requirements. These advantages are due to the use of a constraint based approach to new schedule creation used in tandem with dependency analysis techniques based on reason maintenance systems (de Kleer, 1986) and partial order backtracking (Ginsberg and McAllister, 1995; Spragg and Kelleher, 1996).     

Understanding continuance intention of knowledge creation using extended expectation–confirmation theory: an empirical study of Taiwan and China online communities

Grounded on expectation–confirmation theory (ECT), this study proposes an integrated model aiming to understand how participants' continuance intention of knowledge creation and satisfaction are affected by their perceived identity verification (PIV) and performance expectancy in an online community. To assess the theoretical model, we surveyed two online communities – Baidu (China) and Yahoo knowledge+ (Taiwan), including 213 and 216 useable responses, respectively. Both PIV and performance expectancy are positively associated with continuance intention of knowledge creation. In Baidu community, satisfaction is affected either directly by performance expectancy or indirectly by PIV (through performance expectancy). Our findings have implications for both practice and theory.     

Climbing robots for maintenance and inspections of vertical structures—A survey of design aspects and technologies

The maintenance and inspection of large vertical structures with autonomous systems is still an unsolved problem. A large number of different robots exist which are able to navigate on buildings, ship hulls or other human-made structures. But, most of these systems are limited to special situations or applications. This paper deals with different locomotion and adhesion methods for climbing robots and presents characteristics, challenges and applications for these systems. Based on a given set of requirements these principles are examined and in terms of a comprehensive state-of-the-art more than hundred climbing robots are presented. Finally, this schematics is applied to design aspects of a wall-climbing robot which should be able to inspect large concrete buildings.     

The pleasure of being (there?): an explorative study into the effects of presence and identification on the enjoyment of an interactive theatrical performance using omnidirectional video

This study explores how participants in an immersive theatrical performance perceive their role in the virtual environment (VE) and the effects of this perception on how they experience the performance as a whole. Using a quasi-experimental 2 × 2 design, narrative and task-based search was manipulated to explore the effects on spatial presence, social presence, identification and enjoyment. Results show that the effect of spatial presence on enjoyment of the performance is entirely mediated by identification with the role of the self in the VE. This could have interesting consequences for the experience of more narrative VE’s and suggests that the role of identification is something to explore further in future presence research.     

A new method of speech transmission over space time block coded co-operative MIMO–OFDM networks using time and space diversity

Reliable and good quality of service for speech transmission over wireless network has been a major challenge for the communication engineers and researchers. In this paper a new technique of speech compression and transmission using different Daubechies wavelets in a space time block coded co-corporative MIMO–OFDM networks using time and space diversity has been proposed. The main focus has been laid on design and development of wavelet based compression of multimedia signals for cooperative MIMO–OFDM system. We tried to find out various major issues regarding the wavelet compression of a speech signal. These issues include choice of a wavelet, decomposition level and thresholding criteria suitable for speech compression and transmission in co-operative MIMO–OFDM systems. A wavelet based speech compression technique using hard and soft thresholding algorithm has been proposed. The work shows that wavelet compression with QPSK modulation is a promising compression technique in a cooperative MIMO–OFDM system which makes use of the elegant theory of wavelets. The performance has been evaluated using mean square error, peak signal to noise ratio, compression ratio, bit error rate, and retained signal energy. It has been found that the transmitted speech signal is retrieved well under noisy conditions at higher order Daubechies wavelets. From the results it is clear that proposed technique aims at a radio access technology that can provide service performance comparable to that of current fixed Line accesses. To evaluate the performance of the proposed method, various performance parameters have been compared with previously implemented techniques and it has been found that the proposed work shows better performance as compared to the already existing techniques.     

Regional land cover mapping in the humid tropics using combined optical and SAR satellite data—a case study from Central Sulawesi,Indonesia

The frequent mapping of the spatial extent of land cover and its change from satellite data at the regional level provides essential input to spatially explicit land use analysis and scenario modelling. The accuracy of a land cover map is the key factor describing the quality of a map, and hence affecting the results of land use modelling. In tropical regions, land cover mapping from optical satellites is hampered by cloud coverage and thus alternative data sources have to be evaluated. In the present study, data from Landsat‐ETM+ and Envisat‐ASAR satellite sensors were tested for their ability to assess small scaled landscape patterns in a tropical environment. A focus was on the detection of intensively managed perennial and intra‐annual cropping systems (cocoa, rice). The results confirm previous knowledge about the general potential and advantages of multi‐temporal SAR data compared to mono‐temporal SAR‐based mapping but also show the limitations of different polarization modes in SAR analysis for land cover mapping. In the present case study, cross‐polarized data from Envisat‐ASAR did not yield notable profit for tropical land cover mapping compared to common, co‐polarized time series of ASAR data. However, the general outcome of the study underlines the synergy of optical and radar satellite data for land cover mapping in tropical regions.     

Optimization of concrete mix proportioning using a flattened simplex–centroid mixture design and neural networks

The primary objective of this research was to combine three technologies, namely design of experiments (DOE), artificial neural network (ANN), and mathematical programming (MP), into an integrated methodology for mixing concrete containing SP, fly ash, and slag, consistent with desirable structural grade concrete properties. The function of DOE and ANN is to reduce the number of test mixes and specimens without sacrificing the accuracy of evaluating the effects and the interactions of variations of the components on workability and compressive strength. The function of the MP is to optimize the mixture to lower the cost while keeping the concrete to satisfy required properties. The scope of the research was limited to concrete with compressive strengths 25, 32.5, 40, 47.5, and 55 MPa, and workability 5, 10, 15, 20, 25 cm in slump; therefore, there were 5 × 5 = 25 concrete mixtures. The methodology proved to be applicable for concrete mixes with the above-mentioned wide range of strength and workability. It was also found that (1) the early strength requirement played the dominant role in low and medium strength concrete, while the late strength requirement played the dominant role in high strength concrete, and (2) the workability constraint played a critical role in all concrete except for concrete with low workability.     

Modeling of static friction in closed-loop kinematic chains—Uniqueness and parametric sensitivity problems

Problems with uniqueness and high parametric sensitivity of the solution of equations of motion, encountered in the static friction regime, are addressed. Friction in joints of a multibody system with closed-loop kinematic chains is discussed. Three different models of friction are studied: the discontinuous Coulomb model with stiction regime represented in terms of additional constraints; the approximate Coulomb model, smoothed in the vicinity of zero relative velocity; and the LuGre model with presliding displacements represented in terms of auxiliary state variables. Firstly, a rigid body model is investigated. It is shown that in the case of constraint addition approach, problems with uniqueness of solution emerge in the static friction regime. In the case of continuous models of friction, the solution in the stiction regime and its vicinity is highly sensitive to some hardly measurable or arbitrarily chosen parameters of the model of friction. Origins of nonuniqueness and high sensitivity are investigated, and the questionable credibility of the stiction regime simulation results is discussed. Secondly, a simplified model of body and joint elasticity is introduced to investigate the impact of flexibility on the mechanism frictional behavior. It is shown that taking the flexibility into consideration may eliminate the uniqueness and sensitivity problems. Moreover, the quantities that represent flexibility may be regarded as the key factors influencing the results of stiction regime simulation. Five examples are provided to illustrate the presented considerations.     

A study of substitution,using nominal techniques and Fraenkel–Mostowksi sets

Fraenkel–Mostowski (FM) set theory delivers a model of names and alpha-equivalence. This model, now generally called the ‘nominal’ model, delivers inductive datatypes of syntax with alpha-equivalence — rather than inductive datatypes of syntax, quotiented by alpha-equivalence.The treatment of names and alpha-equivalence extends to the entire sets universe. This has proven useful for developing ‘nominal’ theories of reasoning and programming on syntax with alpha-equivalence, because a sets universe includes elements representing functions, predicates, and behaviour.Often, we want names and alpha-equivalence to model capture-avoiding substitution. In this paper we show that FM set theory models capture-avoiding substitution for names in much the same way as it models alpha-equivalence; as an operation valid for the entire sets universe which coincides with the usual (inductively defined) operation on inductive datatypes.In fact, more than one substitution action is possible (they all agree on sets representing syntax). We present two distinct substitution actions, making no judgement as to which one is ‘right’ — we suspect this question has the same status as asking whether classical or intuitionistic logic is ‘right’. We describe the actions in detail, and describe the overall design issues involved in creating any substitution action on a sets universe.Along the way, we think in new ways about the structure of elements of FM set theory. This leads us to some interesting mathematical concepts, including the notions of planes and crucial elements, which we also describe in detail.     

Cognitive analysis of experts’ and novices’ concept mapping processes: An eye tracking study

The goal of this study was to explore how designated experts (subject experts with extensive experience in science education and concept mapping) and novices (pre-service teachers) establish concept map (CM) development processes while considering their cognitive processes. Two experiments were conducted in which eye-tracking, written, and verbal data were collected from 29 novices and 6 subject matter experts. The results showed that despite some similar strategies, novices and experts followed different patterns during the CM development process. Both experts and novices embraced deductive reasoning and preferred hierarchical type CMs. Additional points studied during the process include filling out requested information in different orders, branch construction pattern, content richness and progress pattern. Furthermore, eye behavior patterns also differed among experts and novices. Expert participants differed from novices in all eye behavior metrics (fixation count, fixation and visit duration for specific actions). Novices’ fixation count (FC) numbers were higher than the experts’ during the entire process and in specific periods. In conclusion, these pattern differences affect the CM development process directly. Considering the patterns revealed in the study may help instructors guide learners more adequately and effectively.