Linear Layout Research Articles

The “Art of Trellis Decoding” Is Fixed-Parameter Tractable

Given n subspaces of a finite-dimensional vector space over a fixed finite field $\mathbb F$, we wish to find a linear layout $V_1,V_2,\ldots,V_n$ of the subspaces such that $\dim((V_1+V_2+\cdots+V_i) \cap (V_{i+1}+\cdots+V_n))\le k$ for all i, such a linear layout is said to have width at most k. When restricted to 1-dimensional subspaces, this problem is equivalent to computing the trellis-width (or minimum trellis state-complexity) of a linear code in coding theory and computing the path-width of an $\mathbb F$-represented matroid in matroid theory. We present a fixed-parameter tractable algorithm to construct a linear layout of width at most k, if it exists, for input subspaces of a finite-dimensional vector space over $\mathbb F$. As corollaries, we obtain a fixed-parameter tractable algorithm to produce a path-decomposition of width at most k for an input $\mathbb F$-represented matroid of path-width at most k, and a fixed-parameter tractable algorithm to find a linear rank-decomposition of width at most k for an input graph of linear rank-width at most k. In both corollaries, no such algorithms were known previously. It was previously known that a fixed-parameter tractable algorithm exists for the decision version of the problem for matroid path-width, a theorem by Geelen, Gerards, and Whittle~(2002) implies that for each fixed finite field $\mathbb F$, there are finitely many forbidden $\mathbb F$-representable minors for the class of matroids of path-width at most k. An algorithm by Hlin\v{e}n\'y (2006) can detect a minor in an input $\mathbb F$-represented matroid of bounded branch-width. However, this indirect approach would not produce an actual path-decomposition. Our algorithm is the first one to construct such a path-decomposition and does not depend on the finiteness of forbidden minors.

A new 3D observation system designed for a seismic ahead prospecting method in tunneling

The tunnel seismic ahead prospecting method is usually used to estimate adverse geology ahead of a tunnel face. The observation system plays an important role in tunnel seismic ahead prospecting, which helps to obtain accurate imaging results. Optimizing the observation system is a key issue for seismic ahead prospecting. In this paper, observation layouts are evaluated and a new three-dimensional (3D) observation system is proposed by imaging results analysis. For linear and 3D layouts, imaging result analysis in this paper indicates that the mirror artifact caused by the linear layout (Which sets sources and geophones on a straight line) can be suppressed by the 3D layout, due to its energy concentration and convergence. Moreover, reflections using 3D layout identify real abnormal bodies better than the linear layout. Moreover, conventional observation layouts often use shot point on the tunnel face or front sidewall, which makes it difficult to filter interference waves from the back of the tunnel face. To solve this problem, typical numerical examples are conducted, and imaging results of observation layouts with shot point on front sidewall, tunnel face or back sidewall are studied. Results show shot point on the back sidewall helps to separate waves, suppress interference waves and extract effective waves (reflected P-waves by discontinuities) by apparent velocity filtering method, so shot point is designed on the back sidewall to get high-quality records. To balance record quality and application convenience, a new 3D observation system is proposed with 12 geophones and 10 shot points in a special arrangement. Compared with a linear layout, practical testing and application using the new 3D system indicate the main fractured zones are accurately identified and located, which proves the reliability and practicability of the new observation system.

CONTRIBUTION OF COMPUTATIONAL SIMULATION FOR LAYOUT ANALYSIS IN A WOODEN FURNITURE INDUSTRY

ABSTRACT The objective of this study was to balance the production line and analyze the layout of the sewing sector in a furniture industry. Using the Arena software, a simulation model was constructed that represented the real system consisting of a cellular layout with 3 groups of 5 seamstresses, who produced 57 different types of products divided into three families, in a daily working day of 625 minutes in the months of February to August and 725 minutes in the months of September to January. The model was quantitatively validated among the managers of the studied industry. The obtained results allowed conclusions with an error of less than 1% in the daily quantity of pieces produced with 99% statistical confidence. Therefore, three scenarios related to the organization of the work environment and the balancing of the production line were constructed, and those include: i) linear layout, and the balancing allowed the division of five seamstresses for families 1 and 2, and three seamstresses for family 3; ii) study of the layout by processes, so that the best balance was constituted of two groups with seven seamstresses; iii) similar to scenario 2 but with six seamstresses in group 1 and seven seamstresses in group 2. It was verified that the modified, alternative scenario 2 is more advantageous for the organization, since it presents greater productivity compared to all other scenarios and to the real system, so the company can increase its production capacity by simply modifying the layout and organizing the work environment.

PENGARUH LAYOUT TEMPAT DUDUK LINEAR DALAM RUANG KULIAH TERHADAP PENYEBARAN KEPADATAN POSISI DUDUK MAHASISWA (Studi Kasus: Ruang Kuliah Jurusan Desain Interior - ITB)

Title: Effect Of Linear Seating Arrangements on Students Seating Preferences Density In The Classroom Seating arrangement in a classroom is one of classroom management method. In general, a college classroom in Indonesia applying linear layout seating arrangement with the front of the classroom as its orientation. Observations carried out on two classrooms and 70 students of Interior Design Major at Faculty of Art and Design in ITB. Petrel software were used to generate data such as image density deployment in a calssroom.The results of the analysis of observational data indicates that in the linear seating arrangement,which is usually applied in a classroom, a high density of students sitting position occurs in the area behind the classroom or the most distant from the source material. It is known to potentially create an unproper classroom atmosphere for a lecture to be established. Keywords: layout, room, position, seat

Effect of Linear Seating Arrangements on Students Seating Preferences Density in The Classroom

Seating arrangement in a classroom is one of classroom management method. In general, a college classroom in Indonesia applying linear layout seating arrangement with the front of the classroom as its orientation. Observations carried out on two classrooms and 70 students of Interior Design Major at Faculty of Art and Design in ITB. Petrel software were used to generate data such as image density deployment in a calssroom.The results of the analysis of observational data indicates that in the linear seating arrangement,which is usually applied in a classroom, a high density of students sitting position occurs in the area behind the classroom or the most distant from the source material. It is known to potentially create an unproper classroom atmosphere for a lecture to be established.

Linear layouts of weakly triangulated graphs

A graph [Formula: see text] is said to be triangulated if it has no chordless cycles of length 4 or more. Such a graph is said to be rigid if, for a valid assignment of edge lengths, it has a unique linear layout and non-rigid otherwise. Damaschke [Point placement on the line by distance data, Discrete Appl. Math. 127(1) (2003) 53–62] showed how to compute all linear layouts of a triangulated graph, for a valid assignment of lengths to the edges of [Formula: see text]. In this paper, we extend this result to weakly triangulated graphs, resolving an open problem. A weakly triangulated graph can be constructively characterized by a peripheral ordering of its edges. The main contribution of this paper is to exploit such an edge order to identify the rigid and non-rigid components of [Formula: see text]. We first show that a weakly triangulated graph without articulation points has at most [Formula: see text] different linear layouts, where [Formula: see text] is the number of quadrilaterals (4-cycles) in [Formula: see text]. When [Formula: see text] has articulation points, the number of linear layouts is at most [Formula: see text], where [Formula: see text] is the number of nodes in the block tree of [Formula: see text] and [Formula: see text] is the total number of quadrilaterals over all the blocks. Finally, we propose an algorithm for computing a peripheral edge order of [Formula: see text] by exploiting an interesting connection between this problem and the problem of identifying a two-pair in [Formula: see text]. Using an [Formula: see text] time solution for the latter problem, we propose an [Formula: see text] time algorithm for computing its peripheral edge order, where [Formula: see text] and [Formula: see text] are respectively the number of edges and vertices of [Formula: see text]. For sparse graphs, the time complexity can be improved to [Formula: see text], using the concept of handles [R. B. Hayward, J. P. Spinrad and R. Sritharan, Improved algorithms for weakly chordal graphs, ACM Trans. Algorithms 3(2) (2007) 19pp].

Investigating wintertime pedestrian wind environment and user perception in dense residential neighbourhood in a city of hot-summer and cold-winter climate zone, China

Urban wind environment could have an impact on pedestrian’s comfort and safety, as well as pollution dispersion and building energy consumption. For cities in the hot-summer and cold-winter climate zone of China, a proper design residential neighbourhoods is important to facilitate urban ventilation in hot and transient seasons and to protect users from strong winds in cold season. This paper reports the results of field measurements and a questionnaire survey in a large residential development with three different types of housings. Micrometeorology measurement was carried out at the pedestrian height level as well as at a rooftop reference station. Pedestrians’ subjective perception on wind and thermal comfort was recorded through a guided interview and questionnaire survey during the measurement. The measured wind velocity ratio is highest in the long-linear high-rise building layout, and is the lowest in the mid-rise linear building layout. Eight-seven per cent of respondents felt fairly comfortable living in the long-linear high-rise building layout, only 7% less than the mid-rise building layout. For similar housing forms in Shanghai, the wintertime wind shelter may not be critical compared with summertime ventilation requirement, and that the site planning and housing design should focus mainly on summertime wind channelling.

Linear Rank-Width of Distance-Hereditary Graphs I. A Polynomial-Time Algorithm

Linear rank-width is a linearized variation of rank-width, and it is deeply related to matroid path-width. In this paper, we show that the linear rank-width of every n-vertex distance-hereditary graph, equivalently a graph of rank-width at most 1, can be computed in time $${\mathcal {O}}(n^2\cdot \log _2 n)$$O(n2·log2n), and a linear layout witnessing the linear rank-width can be computed with the same time complexity. As a corollary, we show that the path-width of every n-element matroid of branch-width at most 2 can be computed in time $${\mathcal {O}}(n^2\cdot \log _2 n)$$O(n2·log2n), provided that the matroid is given by its binary representation. To establish this result, we present a characterization of the linear rank-width of distance-hereditary graphs in terms of their canonical split decompositions. This characterization is similar to the known characterization of the path-width of forests given by Ellis, Sudborough, and Turner [The vertex separation and search number of a graph. Inf. Comput., 113(1):50---79, 1994]. However, different from forests, it is non-trivial to relate substructures of the canonical split decomposition of a graph with some substructures of the given graph. We introduce a notion of `limbs' of canonical split decompositions, which correspond to certain vertex-minors of the original graph, for the right characterization.

Lithography-Aware Analog Layout Retargeting

Photolithographic defects during manufacture cannot only result in significant yield loss in digital integrated circuits, but are also deemed as an important factor in evaluating the quality of analog layouts. In this paper, we propose a graph-based lithography-aware analog layout retargeting methodology. We build up our fault model based on a classical defect size distribution function, geometrical critical area analysis, and probability of failure (POF). The objective of our algorithm is to minimize POF by intelligent redundant space allocation scheme during layout compaction. The optimizations handle the whole analog layout area by global wire widening, intradevice wire shifting (WS), and interdevice WS, which are achieved by updating the constraint-graph representation of the layout. Moreover, we propose an extra space allocation approach that can further reduce POF by an inconsiderably small chip-area compromise. The yield improvement and superior effectiveness of our algorithm are exhibited by retargeting operational amplifiers and being compared with a traditional linear programming-based layout compaction method and a well-known even wire distribution scheme.

Minimizing operators’ walking times into a linear system layout

This paper deals with the assignment of stations to operators into flexible manufacturing systems by minimizing the operators’ walking times over a given planning horizon. The manufacturing system is supposed to present a linear layout where the stations are aligned along a longitudinal axis. Stations are flexible (so that different jobs can be scheduled on the same station along the planning horizon) and may differ from each other in terms of degree of automation and, consequently, in terms of amount of human labor involved. Thus, two or more stations might share the same operator within the working shift and, consequently, the assignment of the optimal subset of stations to each operator is anything but trivial. Hence, a mixed-integer linear programming model is proposed which takes into account (and minimizes) the travel walking distances of the operators according to the assigned subset of stations. Other realistic constraints, such as the actual availability of the operators and the requirement stating that each scheduled job has to be assigned to a single operator for its entire duration, are included in the model.The validity of the model is proved by discussing a real-world case study from the plastic industry.

Visual transcripts

Blackboard-style lecture videos are popular, but learning using existing video player interfaces can be challenging. Viewers cannot consume the lecture material at their own pace, and the content is also difficult to search or skim. For these reasons, some people prefer lecture notes to videos. To address these limitations, we present Visual Transcripts , a readable representation of lecture videos that combines visual information with transcript text. To generate a Visual Transcript, we first segment the visual content of a lecture into discrete visual entities that correspond to equations, figures, or lines of text. Then, we analyze the temporal correspondence between the transcript and visuals to determine how sentences relate to visual entities. Finally, we arrange the text and visuals in a linear layout based on these relationships. We compare our result with a standard video player, and a state-of-the-art interface designed specifically for blackboard-style lecture videos. User evaluation suggests that users prefer our interface for learning and that our interface is effective in helping them browse or search through lecture videos.

Linear layout of locally twisted cubes

ABSTRACTThe hypercube network is one of the most popular parallel computing networks since it has a simple structure and is easy to implement. The locally twisted cube is a newly introduced variant of the hypercube which has the same number of nodes and same number of connections per node as the hypercube, but has only half the diameter and better graph embedding capability as compared to hypercube. In this paper, we show that an n-dimensional locally twisted cube is constructed by forming a matching between the nodes of two disjoint copies of an -dimensional hypercube. In addition, we embed the locally twisted cube into path with minimum layout.

A general number-to-space mapping deficit in developmental dyscalculia

Previous research on developmental dyscalculia (DD) suggested that deficits in the number line estimation task are related to a failure to represent number magnitude linearly. This conclusion was derived from the observation of logarithmically shaped estimation patterns. However, recent research questioned this idea of an isomorphic relationship between estimation patterns and number magnitude representation. In the present study, we evaluated an alternative hypothesis: impairments in the number line estimation task are due to a general deficit in mapping numbers onto space.Adults with DD and a matched control group had to learn linear and non-linear layouts of the number line via feedback. Afterwards, we assessed their performance how well they learnt the new number-space mappings. We found irrespective of the layouts worse performance of adults with DD. Additionally, in case of the linear layout, we observed that their performance did not differ from controls near reference points, but that differences between groups increased as the distance to reference point increased.We conclude that worse performance of adults with DD in the number line task might be due a deficit in mapping numbers onto space which can be partly overcome relying on reference points.

Optimization of Linear Layout Problem in Flexible Manufacturing System Using Evolutionary Algorithms - Case Study

Linear layout is the commonly major preferred arrangement of the flexible manufacturing systems (FMS). The proposed enhanced sheep flock heredity algorithm to solving the unequal area linear layout problem through the real case study problem. The proposed model is to minimize the transportation cost with non-overlapping. Computational results show that proposed sheep flock heredity algorithm (SFHA) can obtain better than particle swarm optimization (PSO) and existing method.

A novel computational approach to combine the optical and thermal modelling of Linear Fresnel Collectors using the finite volume method

A computational approach is presented, which uses the finite volume (FV) method in the Computational Fluid Dynamics (CFD) solver ANSYS Fluent to conduct the ray tracing required to quantify the optical performance of a line concentration Concentrated Solar Power (CSP) receiver, as well as the conjugate heat transfer modelling required to estimate the thermal efficiency of such a receiver. A Linear Fresnel Collector (LFC) implementation is used to illustrate the approach. It is shown that the Discrete Ordinates method can provide an accurate solution to the Radiative Transfer Equation (RTE) if the shortcomings of its solution are resolved appropriately in the FV CFD solver. The shortcomings are due to false scattering and the so-called ray effect inherent in the FV solution. The approach is first evaluated for a 2-D test case involving oblique collimated radiation and then for a more complex 2-D LFC optical domain based on the FRESDEMO project. For the latter, results are compared with and validated against those obtained with the Monte Carlo ray tracer, SolTrace. The outcome of the FV ray tracing in the LFC optical domain is mapped as a non-uniform heat flux distribution in the 3-D cavity receiver domain and this distribution is included in the FV conjugate heat transfer CFD model as a volumetric source. The result of this latter model is the determination of the heat transferred to the heat transfer fluid running in the collector tubes, thereby providing an estimation of the overall thermal efficiency. To evaluate the effectiveness of the phased approach in terms of accuracy and computational cost, the novel 2-D:3-D phased approach is compared with results of a fully integrated, but expensive 3-D optical and thermal model. It is shown that the less expensive model provides similar results and hence a large cost saving. The novel approach also provides the benefit of working in one simulation environment, i.e. ANSYS Workbench, where optimisation studies can be carried out to maximise the performance of linear CSP reflector layout and receiver configurations.

Lean principles and simulation optimization for emergency department layout design

Purpose – The purpose of this paper is to use lean principles and simulation optimization on solving a combined hospital emergency department (ED) layout design and staff assignment problem. Design/methodology/approach – This study is based on value stream mapping for the design and analysis of the ED. Subsequently, the authors investigate cellular manufacturing design, which addresses the decisions of continuous steps in a cell simultaneously and considers the optimal staff assignment. A simulation based on the case study is used for these methodologies. Simulation optimization is then used to optimize the staff assignments, minimize the waiting time and maximize the service level. Findings – The linear layout outperformed in both waiting time and service level. The patients’ average waiting time is reduced from 78 to 38 minutes. The service level increased from 54.86 to 88.55 percent. Moreover, the number of nurses was reduced from nine to six. Research limitations/implications – First, the tests for model accuracy were performed using the actual arrival rate; however, seasonal variation should be reflected. Second, the staffing levels varied were not tracked. Third, the accuracy of individual patient treatment paths can be dynamic. Fourth, the 25 percent of delays in transferring a patient to an inpatient bed will be discussed in future studies. Practical implications – A practical case is adopted for empirical illustrations. Originality/value – The proposed methodology innovatively solved a practical application and the results are promising.

Linear Layout of Directed Grid Graph

A linear layout φ of a directed graph is a layout that provides a topological sorting of the vertices such that for any arc (u, v), φ(u) < φ(v). In this paper we discuss the linear layout of directed grid and other related architectures.

Hybrid PSO – CP technique for the synthesis of non-uniform linear arrays with maximum directivity

A technique to synthesize maximum directivity non-uniform linear layouts subjected to upper bounds on the power pattern is presented. The approach is based on a nested strategy combining an outer particle swarm-based optimization and an inner convex programming solver by taking advantage of the convexity of the synthesis with respect to the excitation coefficients when fixing the array layout. Selected numerical results are discussed to assess the effectiveness, the flexibility, and the limitations of the proposed technique.

Becoming jelly

This paper calls for a debate concerning the dominant tropes, which we have assigned the power to define learning processes in higher education today. The argument of the paper takes a critical stand towards the tropes of taxonomy-based and Bildung-oriented understandings of learning processes and student voice in higher education. We argue that learning processes are more than mere phenomena of linear progression capable of being measured based on pre-set criteria for learning outcomes. On the other hand, we do not argue, that it is productive to take the easy way out using an abstract and shadowy vocabulary of Bildung, authenticity and personal growth. Instead we call for a new vocabulary in educational theory, which is capable of addressing the half-formed, premature and idiosyncratic dimensions of learning processes present in the everyday life of higher education. Inspired by the jelly as a metaphor, and drawing on thinkers such as Richard Sennett, Graham Harman and Friedrich Nietzsche, we call for a gelatinous pedagogy, which, in thought and language, match the motley-coloured, mongrel and queer developmental processes and strategies applied by students and teachers in higher education practice. By developing and applying the jelly as a new metaphor for learning processes and student voice in higher education we are able to address critical issues otherwise overlooked. Out of this application three findings and one suggestion for further research emerge: Firstly, vocabularies for understanding learning processes must have the ambition of making visible those queer processes. This must be done in a language and using a vocabulary, which has gelatinous qualities enabling the capability to grasp specific learning experiences in situ. Secondly, such a language should embrace the tentative, uncertain and troublesome character of learning processes – hereby acknowledging that such processes might never reach an end point and therefore not necessarily lead anywhere. Thirdly, an understanding of learning processes, therefore, cannot be adequately understood as a fixed structure or linear layout, but must rather be approached as jelly-like structures of entanglement and swarm. Fourthly, and finally, the challenge for understanding networked learning within higher education in a more nuanced way can be met by developing a gelatinous pedagogy; a pedagogy linguistically and conceptually sensitive to the multifarious dimensions of learning and being whether these be skills, forms of identity, or sheer ambivalence and obscurity in thought.

A priori mapping of historical water-supply galleries based on archive records and sparse material remains. An application to the Amaniel qanat (Madrid, Spain)

Engineering heritage refers to a broad variety of items of social, economic, aesthetic or historic relevance, including roads, dams, buildings and supply networks. Due to their utilitarian nature, their heritage value is often overlooked. This occurs even with those infrastructures that have played an essential role in underpinning the daily existence of entire civilizations. Underground water-supply networks provide an excellent example. Although there are exceptions, water networks tend to be functional in design, rather than monumental. Moreover, they present intricate linear layouts that often span several kilometres. This means they are costly to maintain once their operational life is over, and that they are prone to abandonment and destruction. Devising a priori protection strategies is important to preserve these valuable cultural assets. The following pages present a method to map linear structures based on archive records and sparse material remains. The method is illustrated through its application to the Amaniel qanat, a water-supply gallery built in Madrid, Spain, in the early 17th Century. An appraisal of the known remains was carried out first, leading to an inventory of galleries, shafts, shaft caps and deposits. This was followed by a thorough survey of over one thousand handwritten manuscripts, including physical descriptions of the aqueduct, budget accounts or water metering campaigns, among other documents. Known remains and written evidence were matched against original and auxiliary maps to reconstruct the itinerary of the aqueduct. This led to the identification of sectors where it is still possible to find remains in good condition. Thus, a priori mapping is advocated a valuable technique to locate and preserve these remains, as well as to devise non-invasive surveys and establish heritage protection zones.