Efficient Layout Research Articles

Improving patient timeliness of care through efficient outpatient clinic layout design using data-driven simulation and optimisation

ABSTRACTWith greater demand for outpatient services, the importance of patient-centric clinic layout design that improves timeliness of patient care has become more elucidated. In this paper, a novel simulation-optimisation (SO) framework is proposed focusing on the physical and process flows of patients in the design of a paediatric orthopaedic outpatient clinic. A discrete-event simulation model is used to estimate the frequency of movements between clinic units. The resulting information is utilised as input to a mixed integer programming (MIP) model, optimising the clinic layout design. In order to solve the MIP model, Particle Swarm Optimisation (PSO), a metaheuristic approach enhanced with several heuristics is utilised. Finally, the optimisation model outputs are evaluated with the simulation model. The results demonstrate that improvements to the quality of the patient experience can be achieved through incorporating SO methods into the clinic layout design process.

A New Two-Stage Approach for a Bi-Objective Facility Layout Problem Considering Input/ Output Points Under Fuzzy Environment

Facility layout problem is one of the most important problems in a huge range of industries and services organizations. Simultaneous study of some qualitative and quantitative parameters like closeness relationship between facilities, physical constraints such as input/output points and how to arrange facilities can play a key role to determine the facility layout. Considering these parameters can lead to reduce production costs, increase production capacity, and remove additional displacements. A two-stage approach is proposed to achieve these goals. In the first stage, a goal programming model is proposed to determine weights of the attributes based on the experts' opinions with different preference representation structures. Afterwards, the closeness ratings of the facilities are calculated using weights of attributes. In the second stage, an efficient layout is designed by determining facilities placement sequence, location of the next facility adjacent to the previous one, location of input/output points, and rectilinear feasible shortest path between facilities. Two meta-heuristic algorithms including particle swarm optimization and genetic algorithm are designed due to computational complexity. The objective function is to minimize the sum of products distance between facilities and closeness rating and also to minimize the dead space. A case study of an Auto Body Parts company is demonstrated to verify the efficiency of the proposed two-stage approach. Furthermore, in order to assess the performance of the proposed approach, a comparison is drawn between the proposed approach and five existing approaches in the literature to solve different problems by using the two meta-heuristic algorithms.

Cellular demanufacturing layout in a rail industry: End-of- life components reusability

Rail manufacturing industry across the globe has been growing exponential since the inception of rail into transportation systems. Freight and passenger trains manufacturing contributes a greater proportion to the rail industry economic impact. The passenger trains are a mode of transport for both poor and rich people in Africa. Due to lack of appropriate demanufacturing plant layouts suited for recovering end-of-life (Eol) components, most of components are often neglected to the landfills. Most African countries have been importing trains for many years around the globe. Some of these trains have reached or are reaching Eol, which makes it difficult for countries to develop or have appropriate demanufacturing plant layouts or technologies for recovering Eol components. The study reviewed various literature on train life cycle management system and cellular demanufacturing layout configurations applied across various industries in the globe. The study further looked into different hybrid layout modalities and a simulation was used to determine efficient models, which can best suit an African context. The study used a case study of Southern Africa to assess the readiness of countries to gain benefits of circular economy through efficient layouts. The study proposes a sustainable cellular layout conceptual model that will accommodate train components variation.

Analysis of simulated annealing cooling schemas for design of optimal flexible layout under uncertain dynamic product demand

Manufacturing facilities are subjected to many uncertainties such as variability in demand, queuing delays, variable task times, rejects and machine breakdown. These volatilities have a large impact on leap time, inventory cost and delivery performance of a manufacturing unit. To operate efficiently the manufacturing facilities should adapt to these variations. The paper explores the way uncertainties are addressed in designing of flexible optimal layout. Such facility layout problem is known as stochastic dynamic facility layout problem (SDFLP). SDFLP is an NP-hard combinatorial optimization problem, which means the time taken to solve increases exponentially with problem size. To solve SDFLP, the paper presents an adaptation of simulated annealing (SA) meta-heuristic. Various SA cooling schemas are discussed, computed and evaluated for generating the optimal flexible layout. An optimal layout is one that minimises the distance travelled by materials taking into account uncertain product demand (material handling cost). A computer-based tool was developed and analysis was conducted on small to large size problem set. The results showed that SA with exponential cooling schedule provides better solution in terms of layout efficiency and gave better solution as compared to literature.

Assessing Layout Density Benefits of Vertical Channel Devices

Vertical channel devices have been considered as promising candidates for sub-5 nm regime for the reduced area and large driving current. Several styles of layout designs and fabrication details of vertical channel devices have been proposed. However, due to the fast-changing manufacturing constraints for the advanced devices, the most efficient layout structures are still yet to be explored. In this paper, we study the efficiency in terms of cell area of in-bound power vertical channel device layout, which is potentially the most compact vertical layout style. We develop and implement an efficient vertical layout generation framework for in-bound power layout to provide a quick evaluation of cell area given design rules and choices of folding strategies. The results are compared to vertically stacked lateral channel devices and out-bound power vertical channel devices. Both cell-level and chip-level comparisons show that in-bound power layout is more area-efficient than lateral devices and vertical out-bound power layouts.

Warehouse layout and workflow designing at PT. PMS using systematic layout planning method

PT. PMS, a company which has specialization in offshore and onshore services has many equipments to support their service operation. The equipment has been classified into four divisions, Diving, ROV, Cleaning and Painting. The problems observed in PT. PMS warehouse were their disorganized warehouse system which has no fixed layout design. For the purpose of improvement, a new warehouse layout design was proposed in this study to solve the problem. The method of modified Systematic Layout Planning (SLP) has been used to design an efficient warehouse layout. Step by step layout procedure has been done. It consists of Activity Relationship Chart and Activity Relationship Diagram that have been discussed. It is proved from this study that SLP method provides an effective method in layout designing, even in the service company that has many equipments to be stored in an efficient manner.

On the exergy analysis of the counter-flow dew point evaporative cooler

The dew point evaporative cooler has been proposed to replace the mechanical vapor compression chiller in air sensible cooling, for its significantly larger energy efficiency and simpler system layout. Many of the existing studies focused on applying a first-law thermodynamic analysis to the dew point evaporative cooler, however, its performance involving the second-law thermodynamic assessment remains unclear. Therefore, in this paper, an exergy analysis of the counter-flow dew point evaporative cooler is conducted. The exergy performance of the dew point evaporative cooling process is examined by incorporating the first law of thermodynamics for energy and mass balances. A counter-flow dew point evaporative cooler prototype has been designed, fabricated and tested to investigate its cooling performance. A 2-D computational fluid dynamics (CFD) model is then formulated to simulate the flow, temperature and humidity fields of the cooler. The model agrees well with the acquired experimental data with the maximum discrepancy of ±5.6%. The exergy flow, efficiency and efficiency ratio of the cooler are discussed under various simulation conditions. Key findings that emerged from this study reveal that the saturated air state at ambient temperature is the rational dead state to properly describe the physical mechanisms involved in the dew point evaporative cooling process. The exergy efficiency ratio of the dew point evaporative cooler is greater than 1.0, highlighting a remarkable second-law efficiency for air conditioning applications.

Flexible multi-node simulation of cellular mobile communications: the Vienna 5G System Level Simulator

The investigation and prediction of new trends and technologies for mobile cellular networks is of utmost importance for researchers and network providers to quickly identify promising developments. With the verge of the fifth generation of mobile communications (5G), networks become more and more heterogeneous and dynamic while the amount of active users within a cell keeps ever increasing. Therefore, the search for more efficient network layouts and configurations attracts massive attention while on the other hand becomes more and more complex. In this contribution, we present the Vienna 5G system level simulator, which allows to perform numerical performance evaluation of large-scale multi-tier networks, with numerous types of network nodes. The simulator is based on Matlab and is implemented in a modular fashion, to conveniently investigate arbitrary network and parameter constellations, which can be enhanced effortlessly. We first discuss the distinguishing aspects of our simulator platform, describe its structure, and then showcase its functionality by demonstrating the key aspects in more detail.

Concurrent topological optimization of two bodies sharing design space: problem formulation and numerical solution

Topology optimization is a widely used technique for deriving efficient structural layouts for components in many engineering fields. The optimization process deals with the definition of the optimal material distribution of single components subjected to specified loads and boundary conditions, in case made of different materials or with embedded regions corresponding to other components or actuators. In this paper, a novel topology optimization problem is proposed. The case of the concurrent topological optimization of two different components sharing a part of the design spaces is considered. The design problem represents a design situation in which more than one component has to be fitted in an enclosed space and each component has its own load carrying function. In the paper, the problem is solved by a numerical technique able to allocate the common part of the design space to each component. Inside the allocated space, the actual material distribution of the component is optimized by a standard topological optimization algorithm. Numerical examples are provided to show the potentialities of the method. A (simplified) practical design problem is also considered.

An efficient algorithm for embedding exchanged hypercubes into grids

Graph embedding is an important technology in simulating parallel structures and designing VLSI layout. Hypercube is one of the most significant interconnection networks in parallel computing systems. The exchanged hypercube is an important variant of the hypercube, which is obtained by systematically deleting edges from a hypercube. It not only retains several valuable and desirable properties of the hypercube, but also has lower hardware cost. In this paper, we first give an exact formula of minimum wirelength of exchanged hypercube layout into a grid. Furthermore, we propose an O(N) algorithm for embedding exchanged hypercube into a gird with load 1, expansion 1 and minimum wirelength and derive a linear layout of exchanged hypercube with minimum number of tracks and efficient layout areas. Finally, we present simulation experiments of our embedding algorithm on network overhead and total wirelength, which conduce to estimate the total wirelength and chip area.

Sustainable robust layout using Big Data approach: A key towards industry 4.0

A layout design based on large scale (Big) data is more efficient and effective in today's competitive market. Due to variations in product demands, varying product mix, and addition or deletion of products, layout of industry needs to be robust and sustainable. A robust and sustainable industry layout design is capable to handle the variations and is seen as first step towards Industry 4.0 to keep precise and accurate manufacturing of products in given due time. Poor layout design decreases the precision and accuracy in manufacturing of products and increases the production time. To design layout for Industry 4.0, this work proposes an embedded SA based meta-heuristic and principal component analysis (PCA) approach using large scale data to solve sustainable robust stochastic cellular facility layout problem (sustainable-RSCFLP). The data for the problem is collected considering basic 3Vs of Big Data i.e. Volume, Variety, and Velocity. Fourteen different criteria are identified and evaluated by 100 experts to group them based on their Eigen values using PCA. These are Distance, Adjacency, Shape ratio, Flexibility, Maintenance, Accessibility, Hazardous movement, Noise Level, Aesthetic, Safety, WIP and inventory, Space utilization, Capital equipment utilization, and Robustness. These fourteen criteria are clustered in to four factors using PCA approach. These clusters are defined as Material Handling Distance, Maintenance, Adjacency, and Hazard. The material handling distance comprises of three criteria such as Distance, Capital equipment utilization, and space utilization. In the same way, Maintenance comprises of three criteria such as Maintenance, Work in Process and inventory, and Accessibility. Similarly, Adjacency comprises of four criteria such as Shape ratio, Robustness, Adjacency, and Flexibility. Finally, Hazard comprises of four criteria such as Noise level, Aesthetics, Safety and Hazardous movement. In addition to these four clusters, fifth factor i.e. electrical energy consumption (EEC) is taken separately for each layout alternative to make the proposed layout environmentally sustainable. Thus, the proposed layout considers all pillars of sustainability i.e. EEC (maps environmental sustainability), Maintenance and Hazards (maps social sustainability), and Material Handling (maps economic sustainability) for designing cellular facility layout problem. Further, pool of layouts is generated using embedded SA based meta-heuristic. Each layout is evaluated over each clusters and EEC is calculated for each layout as to make the layout design sustainable. Furthermore layouts are ranked using TOPSIS, IRP, and weighted-IRP qualitative approaches, and a consensus ranking is finally provided to select an efficient sustainable robust layout for Industry 4.0.

Seasonal and Spatial Variability of Water Quality and Nutrient Removal Efficiency of Restored Wetland: A Case Study in Fujin National Wetland Park, China

To investigate the spatio-temporal and compositional variation of selected water quality parameters and understand the purifying effects of wetland in Fujin National Wetland Park (FNWP), China, the trophic level index (TLI), paired samples t-test and correlation analysis were used for the statistical analysis of a set of 10 water quality parameters. The analyses were based on water samples collected from 22 stations in FNWP between 2014 and 2016. Results initially reveal that total nitrogen (TN) concentrations are above class V levels (2 mg/L), total phosphorus (TP) concentrations are below class III levels (0.2 mg/L), and that all other parameters fall within standard ranges. Highest values for TN, pH, and Chlorophyll-a were recorded in 2016, while the levels of chemical oxygen demand (CODMn) and biochemical oxygen demand (BOD5) were lowest during this year. Similarly, TN values were highest between 2014 and 2016 while dissolved oxygen (DO) concentrations were lowest in the summer and TP concentrations were highest in the autumn. Significant variations were also found in Secchi depth (SD), TN, CODMn (P < 0.01), TP, and DO levels (P < 0.05) between the inlet and outlet of the park. High-to-low levels of TN, TP, and TDS were found in cattails, reeds, and open water (the opposite trend was seen in SD levels). Tested wetland water had a light eutrophication status in most cases and TN and TP removal rates were between 7.54%–84.36% and 37.50%–70.83%, respectively. Data also show no significant annual changes in water quality within this wetland, although obvious affects from surrounding agricultural drainage were nevertheless recorded. Results reveal a high major nutrient removal efficiency (N and P). The upper limits of these phenomena should be addressed in future research alongside a more efficient and scientific agricultural layout for the regions in and around the FNWP.

Robust and efficient QCA cell-based nanostructures of elementary reversible logic gates

Increasing device density and reducing energy consumption are challenging issues in integrated nanoscale circuits. Reversible logic in quantum-dot cellular automata (QCA) nanotechnology is emerging as a promising candidate to overcome these issues and to introduce new computation paradigms with unique features like nanoscale feature size and ultra-low power dissipation. For the first time, QCA cell-based designs of reversible Feynman, Toffoli, Fredkin, and Peres gates are presented in this paper. These elementary gates are usually used in the synthesis of reversible circuits. The proposed layouts utilize electrostatic interactions between cells within QCA configurations to perform desired functions. All the robust designs are evaluated in terms of hardware complexity and power dissipation using QCADesigner and QCAPro simulation tools. The efficient QCA layouts of proposed gates have notable improvements as compared to the existing ones in terms of gate delay, cell count, area occupation, quantum cost, leakage energy, and switching energy. As a result, the proposed elementary gates via QCA cell level-based design are good candidates for building and developing high-level nanoelectronic reversible circuits.

A game theory based land layout optimization of cities using genetic algorithm

ABSTRACTLayout optimization is carried out to achieve the true economic potential of cities by ensuring optimal land usage. This paper presents a novel framework to resolve conflicts between types of land usage while considering the effect of neighboring land plots to generate efficient city layouts. The optimization problem is modeled as a game between land-usage based players, each trying to maximize payoff based on expected layout modifications. It is worth noting that this framework aims to include multi-stakeholder competition, land patch shaping, and neighbor plot effects. A game-theory based approach is coupled with genetic algorithm in which swapping and resizing operators are used to generate a new solution. A parametric study on fitness evaluation of algorithmic output layouts is presented. The presented optimization framework has been implemented on land usage map of Guwahati, a city in north-east India.

GPU based techniques for deep image merging

Deep images store multiple fragments perpixel, each of which includes colour and depth, unlike traditional 2D flat images which store only a single colour value and possibly a depth value. Recently, deep images have found use in an increasing number of applications, including ones using transparency and compositing. A step in compositing deep images requires merging per-pixel fragment lists in depth order; little work has so far been presented on fast approaches.This paper explores GPU based merging of deep images using different memory layouts for fragment lists: linked lists, linearised arrays, and interleaved arrays. We also report performance improvements using techniques which leverage GPU memory hierarchy by processing blocks of fragment data using fast registers, following similar techniques used to improve performance of transparency rendering. We report results for compositing from two deep images or saving the resulting deep image before compositing, as well as for an iterated pairwise merge of multiple deep images. Our results show a 2 to 6 fold improvement by combining efficient memory layout with fast register based merging.

A Firefly Algorithm Approach for Multirow Facility Layout Problem

The facility layout problem is an optimization problem that makes efficient layouts. Layout design has a prime importance on the performance of manufacturing systems. The facility layout problem (FLP) helps to reduce the material handling costs by a well organized positioning of facilities. The facility layout problems are generally regarded as NP-Hard problems. The different methodologies for solving FLP’s can be exact algorithms, heuristics and meta-heuristics. The exact algorithms are generally used when the number of facilities in the layout is up to 16. For large sized FLP’s, heuristics were developed to attain near optimal solution in reasonable computation times. In the recent literatures, there is a great focus on biology-inspired meta-heuristic algorithms to find most suitable solutions for FLP’s. Firefly Algorithm is a recently developed Meta-heuristic, which represents some of the traits of the firefly behaviour. This paper focuses on the application of firefly algorithm to multi-row facility layout problem with the goal of reducing total material handling cost. A parameter analysis was done and some general FLP’s were solved using the algorithm. A comparative study between Genetic Algorithm and Firefly Algorithm was also performed.

Characterization and Optimization of Inverted-T FinFET Under Nanoscale Dimensions

In this paper, a p-type inverted-T FinFET (IT FinFET) has been optimally structured. Focus is made on analyzing the inferior characteristics reported from the previously fabricated IT FinFETs, and obtaining better performances through a novel structure. IT FinFET has a higher layout efficiency and can thus provide larger drain current ( ${I}_{D}$ ) under the same dimension as that of a silicon-on-insulator (SOI) FinFET by securing the extended channels of ultrathin body (UTB) on the field region. We closely observe the leverages of fin width ( ${W}_{\textsf {fin}}$ ), UTB height ( ${H}_{\textsf {UTB}}$ ), and gate length ( ${L}_{g}$ ) on the operation characteristics using a 3-D technology computer-aided design simulation with quantum-mechanical models. ${W}_{\textsf {fin}}$ below 10 nm is evaluated to be suitable for strong gate controllability. We first examine a critical ${H}_{\textsf {UTB}}$ , beyond which a higher drive current is not obtained even with a greater channel width than that of FinFET. When ${H}_{\textsf {UTB}} = \textsf {3}$ and 10 nm, IT FinFET yields 13.3% and 142% of saturation current improvement compared with SOI FinFET under the same footprint. At extremely scaled ${L}_{g}$ , although the immunity against short-channel effects is slightly weaker than that of SOI FinFET, optimally designed IT FinFET can produce a higher current and demonstrates shorter intrinsic delay times.

Generalized motorcycle graphs for imperfect quad-dominant meshes

We introduce a practical pipeline to create UV T-layouts for real-world quad dominant semi-regular meshes. Our algorithm creates large rectangular patches by relaxing the notion of motorcycle graphs and making it insensitive to local irregularities in the mesh structure such as non-quad elements, redundant irregular vertices, T-junctions, and others. Each surface patch, which can contain multiple singularities and/or polygonal elements, is mapped to an axis-aligned rectangle, leading to a simple and efficient UV layout, which is ideal for texture mapping (allowing for mipmapping and artifact-free bilinear interpolation). We demonstrate that our algorithm is an ideal solution for both recent semi-regular, quad-dominant meshing methods, and for the low-poly meshes typically used in games and movies.

Wide‐Bandgap Small Molecular Acceptors Based on a Weak Electron‐Withdrawing Moiety for Efficient Polymer Solar Cells

Narrow‐bandgap small molecular acceptors (SMAs) with absorption extending into the near‐infrared spectral region such as ITIC derivatives are widely investigated, while the development of their wide‐bandgap counterparts remains largely unexplored. Wide‐bandgap non‐fullerene acceptors (NFAs) are highly desirable and beneficial for constructing efficient device layouts such as ternary blend and tandem solar cells that require multiple light‐harvesting materials with different regions of absorption. In this contribution, the design and synthesis of two wide‐bandgap SMAs (IDT‐TBA and IDDT‐TBA), consisting of a weak electron‐withdrawing moiety (1,3‐diethyl‐2‐thiobarbituric acid, TBA) is presented. Compared to ITIC, this molecular design strategy results in energetically down‐shifted HOMO levels and hence much enlarged bandgaps of 1.91 eV for IDT‐TBA and 1.78 eV for IDDT‐TBA, respectively. Further photovoltaic performance evaluation demonstrates power conversion efficiencies (PCEs) of 6.5% for IDT‐TBA and 7.5% for IDDT‐TBA, respectively, when using PBDB‐T as the electron donor polymer. In addition, time‐delayed collection field (TDCF) experiments suggest that both IDT‐TBA and IDDT‐TBA based cells exhibit field‐independent charge generation with external charge generation efficiencies exceeding 90%, implying negligible geminate recombination losses. The results demonstrate that TBA units are promising and attractive building blocks as weak electron‐withdrawing acceptors to construct wide‐bandgap high‐efficiency SMAs for efficient organic photovoltaic devices.

Efficient data layouts for a three-dimensional electrostatic Particle-in-Cell code

The Particle-in-Cell (PIC) method is a widely used tool in plasma physics. To accurately solve realistic problems, the method requires to use trillions of particles and therefore, there is a strong demand for high performance code on modern architectures. The present work describes performance results of Pic-Vert, a hybrid OpenMP/MPI and vectorized three-dimensional electrostatic PIC code.The code simulates 3d3v Vlasov–Poisson systems on Cartesian grids with periodic boundary conditions. Overall, it processes 590 million particles/second on a 24-core Intel Skylake architecture, without hyper-threading (25 million particles per second per core).The paper presents extensions in 3d of our preliminary 2d results (Barsamian et al., 2017), with highlights on the difficulties and solutions proposed for these extensions. Specifically, our main contributions consist in proposing a new space-filling curve in 3d (called L6D) to improve the cache reuse and an adapted loop transformation (strip-mining) to achieve efficient vectorization. The analysis of these optimization strategies is performed in two-stages, first on a 24-core socket and second on a super-computer, from 1 to 3072 cores, demonstrating significant performance gains and very satisfactory weak scaling results of the code.