Thousands Of Blocks Research Articles

Scheduling as a Constraint Satisfaction Problem (Using the Example of Open-Pit Minе Production Scheduling Problem)

The research described in the work is aimed at developing methods for Scheduling. The fundamental disadvantage of the existing methods of Mixed-Integer Linear Programming in application to the problems under consideration is the fact that they are too demanding on the amount of RAM. The difficulty of applying local search procedures to such high-dimensional problems is to develop an effective way to find an acceptable initial approximation and determine the neighboring state transition function, which would allow achieving the optimum fast enough. In the Operations Research Theory, adding additional conditions to a problem can lead to a fundamental change in the problem-solving scheme. The methods proposed in the study are implemented within the framework of the Constraint Programming Paradigm which makes it possible to represent the subject domain dependencies saving RAM, as well as to provide the ability to step-by-step take into account heterogeneous problem conditions without essentially changing the scheme of finding solutions. A significant part of the research deals with methods of logical inference on constraints to reduce the search space and speed up the computational process. The approach to scheduling is illustrated by the Open-Pit Mine Production Scheduling Problem, which was first proposed to be solved as a Constraint Satisfaction Problem. In order to find the first feasible solution, a «greedy» search method is proposed, the result of which can be improved using the developed hybrid method. Both methods rely on original procedures of inference on constraints. The proposed approach has proven its efficiency for block models with sizes of tens and hundreds of thousands of blocks.

DEEP LEARNING APPROACHES FOR MULTI-CLASS DISEASE DETECTION AND CLASSIFICATION IN RETINAL IMAGES

Many techniques are designed to increase accuracy diagnoses of diseases in retinal images such as hypertensive retinopathy. Convolutional neural networks (CNN) have been employed in various techniques to segment blood vessels in retinal images. These techniques sometimes fail to effectively segment the blood vessels of retina of eye and produce extra noise and we have with this drawback, we present a technique to detect blood vessels in retina of eye images using thousands of blocks (patches) from each of the image. This technique is on a CNN where it contains four convolutional layers followed by relu, max pooling four layers, two layers are fully connected and one layer is the softmax for segmenting blood vessels.

Interlocking Block Assembly With Robots

This article presents a design for interlocking blocks and an algorithm that allows these blocks to be assembled into desired shapes. During and after assembly, the structure is kinematically interlocked if a small number of blocks are immobilized relative to other blocks. There are two types of blocks: cubes and double-height posts, each with a particular set of male and female joints. Layouts for shapes involving thousands of blocks have been planned automatically, and shapes with several hundred blocks have been built by hand. This article also describes a method for assembling structures from blocks in parallel. As a proof of concept, a dual-robot system was used to assemble 48 blocks, forming an interlocking cube-like structure. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —This article was inspired by existing work on interlocking joinery structures, modular robots, and construction robots. We present designs for two interlocking blocks that can be assembled into larger rigid structures. Blocks of this type are a promising future construction material. Only translation is needed to assemble the blocks, simplifying robotic assembly, and the mortarless construction allows for later disassembly and reuse of the blocks. We propose an algorithm that lays out blocks into desired shapes in series and developed a dual-robot system to assemble 48 blocks automatically. Our physical experiments show that joint manufacturing precision is critical to the ease of construction and the rigidity of the finished structure. We also present a layout algorithm that enables parallel assembly, allowing multiple robots to work on the same structure.

Characteristics, potentials, and limitations of open-source Simulink projects for empirical research

Simulink is an example of a successful application of the paradigm of model-based development into industrial practice. Numerous companies create and maintain Simulink projects for modeling software-intensive embedded systems, aiming at early validation and automated code generation. However, Simulink projects are not as easily available as code-based ones, which profit from large publicly accessible open-source repositories, thus curbing empirical research. In this paper, we investigate a set of 1734 freely available Simulink models from 194 projects and analyze their suitability for empirical research. We analyze the projects considering (1) their development context, (2) their complexity in terms of size and organization within projects, and (3) their evolution over time. Our results show that there are both limitations and potentials for empirical research. On the one hand, some application domains dominate the development context, and there is a large number of models that can be considered toy examples of limited practical relevance. These often stem from an academic context, consist of only a few Simulink blocks, and are no longer (or have never been) under active development or maintenance. On the other hand, we found that a subset of the analyzed models is of considerable size and complexity. There are models comprising several thousands of blocks, some of them highly modularized by hierarchically organized Simulink subsystems. Likewise, some of the models expose an active maintenance span of several years, which indicates that they are used as primary development artifacts throughout a project’s lifecycle. According to a discussion of our results with a domain expert, many models can be considered mature enough for quality analysis purposes, and they expose characteristics that can be considered representative for industry-scale models. Thus, we are confident that a subset of the models is suitable for empirical research. More generally, using a publicly available model corpus or a dedicated subset enables researchers to replicate findings, publish subsequent studies, and use them for validation purposes. We publish our dataset for the sake of replicating our results and fostering future empirical research.

Strategy use in probabilistic categorization by rhesus macaques (Macaca mulatta) and capuchin monkeys (Cebus [Sapajus] apella).

Probabilistic categorization tasks present the learner with a set of possible responses and imperfect cue evidence of which response will be rewarded. A single, optimal integration of all available cues into an optimal response is possible given any set of evidence. In contrast, there are many possible uses of the cues that offer the learner suboptimal (but better than chance) responding. We presented a classic probabilistic categorization task to 3 rhesus macaques (Macaca mulatta) and 13 capuchin monkeys (Cebus [Sapajus] apella) to explore what strategies for integration of imperfectly predictive stimulus information would be used by the animals. Using the strategy analysis models that have been previously used to describe human strategy use in probabilistic categorization tasks, we fit each of thousands of blocks of responses to 25 types of response strategies ranging from complex cognitive strategies (e.g., optimal integration of all evidence) to heuristic strategies (e.g., identify a highly predictive cue and respond based only on its presence or absence) to rote behavior (e.g., choosing the same response every trial). Inferences about strategy use were highly stable within animals and were heterogeneous across animals, with some animals never using cue information and others using it fruitfully. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Advantages of Using UAV Digital Photogrammetry in the Study of Slow-Moving Coastal Landslides

The aim of this study is to demonstrate the advantages of using micro drones in the study of large slow-moving landslides, which are widespread along the northwestern coast of Malta. In particular, attention was given to the inventory and analysis of gravity-induced joints and megaclast deposits at four study sites selected due to the presence of remarkable examples of lateral spreads evolving into block slides. The research was carried out by means of Google Earth (GE) image analysis and uncrewed aerial vehicle digital photogrammetry (UAV-DP). UAV-DP outputs enabled the identification and characterization of tens of persistent joints (locally exceeding 150 m) and permitted the size categorization of thousands of blocks. With reference to gravity-induced joints, a favorable agreement was found between existing datasets (mainly based on the integration of GE analysis and field survey) and UAV-DP outputs in terms of the identification of joints and their persistence. Conversely, the use of the UAV-DP technique showed significant advantages in terms of joint aperture determination (even exceeding 1 m) and distribution setting. Regarding the extensive megaclast deposits, UAV-DP enabled the identification of 8943 individuals which, compared with the 5059 individuals identified by GE analysis, showed an increase in the total population of 76%. This is related to the high accuracy of DP-derived orthomosaics and 3D models, which are particularly useful for identifying detached blocks. The inexpensive technique used in this research highlights its potential for being extended to other rocky coastal areas affected by slow-moving landslides.

Effective solution of the long-term open pit production planning problem using block clustering

Production planning of an open pit mine is defined as determining the extraction sequence of blocks in the final pit limit with the goal of maximizing Net Present Value (NPV) while considering the constraints imposed on the mining system. Mathematical programming models are used to optimize long-term open pit production planning problems. In real mines with several thousands of blocks and several scheduling periods, however, these methods lose their efficiency by increasing the number of decision variables, and it is almost impossible to solve and obtain a solution in a reasonable time using current solvers. In this paper, a new method based on block clustering was proposed to reduce the model size. In the first step, blocks are aggregated in clusters called “mother clusters” using the concept of clustering as a mathematical programming problem and solved using Genetic Algorithm (GA). In the second step, the mother clusters are converted to the mining clusters considering the practicality issues. The results of implementing the proposed method on a real deposit showed that block clustering could decrease the number of binary variables from 476,100 to 5,652. This led to a significant reduction in solution time from 372 hours to 23.4 seconds compared to the original block model. The clustering strategy was also able to realize more than 82% of the NPV obtained from scheduling original blocks.

Short and long term optimization for micro-object conveying with air-jet modular distributed system

Smart surface is a new conveying technology composed of a 2D planar surface presenting a matrix of distributed autonomous blocks. Every block contains a micro-electro-mechanical system (MEMS) actuator that controls the transfer of a possible object located above the block to the neighboring blocks, using air-jet forces. The spatial characteristics of the blocks impose some limits on the memory, energy and computation capabilities of the MEMS blocks. On the other hand, the system can reach several thousands of blocks making necessary to propose scalable algorithmic solutions.This paper studies different distributed algorithms to convey an object from an initial to a target position in the smart surface. The conveying policy emphasizes the long term use of the smart surface and the objects conveying efficiency measured by the time of the transfer. The problem stands as an original case of multi-objective Shortest Path problem (MOSP). Original because the quality of a given path is not evaluated by the sum of the weights of its segments, and because the segment weights change according to the used paths as provided by the algorithm itself. Therefore, the efficiency of a given algorithm is assessed on the basis of its performance during a long period of time.We describe here the best way to combine these two objectives and we propose a scalable incremental distributed protocol for objects conveying. The path optimality is adjusted according to the required calculation complexity. The performances of the different algorithmic and modeling variations are analyzed in terms of memory, time, computation and exchanged messages complexity. The obtained results prove the scalability of the algorithm, with linear computational, memory and convergence time complexity, and confirm the improvement of smart surface usage compared to a naive approach. The system lifespan increases of up to 130% on 40 × 40 smart surface, while the transfer cost (time and energy) is reduced. We show also that the computation time of the path with the incremental algorithm can be significantly reduced without significant degradation of the conveying system performance. For example, in a 40 × 40 smart surface, the number of messages is divided by 4 while the number of conveyed objects is only reduced by a ratio of 4%.

Characterization of the lapis lazuli from the Egyptian treasure of Tôd and its alteration using external μ-PIXE and μ-IBIL

Lapis lazuli is among the earliest and most priced ornamental stone worked to produce carvings, beads and inlays as early as the 4th millennium BC. It is an heterogeneous rock composed of blue lazurite Na3Ca(Si3Al3O12)S mixed with other minerals like calcite, diopside and pyrite. The historical source of lapis lazuli in antiquity is supposedly located in Afghanistan, in the Sar-e-Sang district, while other sources are known in Tajikistan and Russia (Baïkal area).This work focuses on the lapis-lazuli of the Egyptian treasure of Tôd dated from Middle Kingdom (20th c. BC). Deposited in four copper boxes, it consists of thousands of blocks of raw lapis lazuli, minute fragments, beads and carvings stylistically dated to various periods. This discovery raises the question of the use of lapis lazuli in ancient Egypt because there is no source of lapis in this country. In addition, most of the lapis lazuli artefacts are strongly weathered. The aim of this work is to understand the alteration process and to verify if its provenance can still be determined.A few artefacts were analysed using the new external microbeam line of the AGLAE facility of the C2RMF. The mineral phases were identified and corresponding trace elements (e.g. Ti, As, Ni, Ba) were ascribed using the quantitative PIXE elemental maps collected on the entire artefacts or on cross-sections. In parallel, the IBIL spectrum recorded for each point in the image provided an additional fingerprint of the luminescent phases, notably mineral species belonging to the cancrinite group. Most alteration products appeared to derive from the oxidation of the pyrite FeS2. It was observed that the alteration process extends to the core of most investigated artefacts. Despite such a strong alteration state, the chemical fingerprints recorded on the studied artefacts proved to be consistent with that of lapis lazuli from historical deposit of Badakshan, Afghanistan, previously investigated using the same μ-PIXE/μ-IBIL protocol.

Usable optimistic fair exchange

Fairly exchanging digital content is an everyday problem. It has been shown that fair exchange cannot be achieved without a trusted third party (called the Arbiter). Yet, even with a trusted party, it is still non-trivial to come up with an efficient solution, especially one that can be used in a p2p file sharing system with a high volume of data exchanged. We provide an efficient optimistic fair exchange mechanism for bartering digital files, where receiving a payment in return for a file (buying) is also considered fair. The exchange is optimistic, removing the need for the Arbiter’s involvement unless a dispute occurs. While the previous solutions employ costly cryptographic primitives for every file or block exchanged, our protocol employs them only once per peer, therefore achieving an O( n) efficiency improvement when n blocks are exchanged between two peers. Our protocol uses very efficient cryptography, making it perfectly suitable for a p-2-p file sharing system where tens of peers exchange thousands of blocks and they do not know beforehand which ones they will end up exchanging. Therefore, our system yields up to one-to-two orders of magnitude improvement in terms of both computation and communication (40 s vs. 42 min, 1.6 MB vs. 200 MB). Thus, for the first time, a provably secure (and privacy-respecting when payments are made using e-cash) fair exchange protocol can be used in real bartering applications (e.g., BitTorrent) [14] without sacrificing performance.

A heuristic approach to long-range production planning of cement quarry operations

Cement manufacturing requires sustained supply of raw materials from limestone quarry. Raw materials inventory in limestone quarry is identified as a block model, usually, consisting of thousands of blocks. Each block consists of a distinct amount of chemical constituents which are vital for cement production. An individual block never satisfies the process quality constraints; therefore, the blending of various quarry blocks with expensive additives purchased from the market becomes a prerequisite. The objective of a quarry production scheduling model is to mine available blocks in a sequence such that cement plant quantity and quality requirements are satisfied. Achieving a solution to the problem, where each block is defined as an integer (0-1) variable, often within reasonable time, has been a challenge for the mining industry. In this article, the complex production scheduling problem is divided into two sub-problems, where quarry sequencing algorithm develops feasible quarry plans and mixed integer linear programming based blending formulation minimises cost by selecting a plan that requires least amount of additives from the market. The implementation of methodology on an existing operation ensures time as well as cost savings compared to the schedules produced manually.

Age of submarine debris avalanches and tephrostratigraphy offshore Ischia Island, Tyrrhenian Sea, Italy

We present an “event stratigraphy” framework built for the last 23 cal ka marine record in the southern offshore of Ischia Island based on AMS 14C dating and tephrostratigraphic analysis of 11 gravity cores. Two collapse events have been recovered in the record: a) the Ischia submarine debris avalanche/debris flow (DA/DF), dated between ~ 3 ka B.P. and 2.4 ka B.P. and possibly between 2.7 ka B.P. and 2.4 ka B.P. (event DF1); b) a former, pre-Holocene, DA/DF older than 23 cal ka B.P. (event DF2). The Ischia DA, with an estimated volume of 1.5 km 3, incorporates thousands of blocks that are still detectable on the sea-floor until 45–50 km far from the island. Our results indicate an age of emplacement younger than previously thought and support the hypothesis that a major catastrophic event occurred when the island was already inhabited by Greek settlers (i.e. after the 7th century BC). Three ash layers have been recognised in the post-DF1 avalanche sequence and correlated with Ischian eruptions occurred between Middle Ages and Roman times. Two tephras recovered in the pre-DF1 succession have been correlated with explosive activity occurred on Ischia and Procida islands from ~ 23 ka to ~ 17.5 ka B.P. The results presented here improve the chronostratigraphic reconstruction of the main eruptive and collapse events that affected Ischia volcano during Late Pleistocene–Holocene and their dispersal at sea. The occurrence of at least two major collapsing events in the past 23 kyr confirms the close genetic relationship between gravity failures and Mt. Epomeo uplift.

Conditional simulation of geologically averaged block permeabilities

Currently available hardware and software for flow simulation can handle up to hundreds of thousands of blocks, or more comfortably tens of thousands of blocks. This limits the discretization of the reservoir model to an extremely coarse grid, say 200 × 200 × 25 for 10 6 blocks. Such a coarse grid cannot represent the structural and petrophysical variability at the resolution provided to geologists by well logs and outcrops. Thus there is no alternative to averaging the impact of all small-scale, within-block, heterogeneities into block ‘pseudos’ or average values. The flow simulator will account for geological description only through those pseudos, hence detailed modelling of geological heterogeneity should not go beyond the information that block pseudos can carry, at least for flow simulation purposes. It is suggested that the present drive in outcrop sampling be clearly redirected at evaluating ‘geopseudos’, i.e. at evaluating how small-scale variability (both structural and petrophysical) of typical depositional units averages out into large blocks' effective transmissivities and relative permeabilities. Outcrop data would allow the building of generic, high-resolution, numerical models of the geo-variability within a typical depositional unit: this is where geology intervenes. Then, this numerical model would be input into a generic flow simulator, single or multiphase, yielding genetic block averages, for blocks of various sizes and geometries: this is where the reservoir engineer intervenes. Next, the spatial statistics of these block averages (histograms, variograms, …) would be inferred: this is where the geostatistician intervenes. Last comes the problem of filling-in the actual reservoir volume with simulated block averages specific to each depositional unit. Because each reservoir is unique, random drawing of block average values from the previously inferred generic distributions would not be enough. The placement of block average values in the specific reservoir volume must be made conditional on local data whether well log, seismic or production-derived. This non-trivial task of ‘conditional simulation’ of block average is the challenge of both the reservoir geologist and geostatistician. This paper proposes an avenue of approach that draws from the pioneering works of Steve Begg at BP-Alaska (1992, 1994) and Jaime Gomez-Hernandez at Universidad of Valencia (1990, 1991).

Building Cheops' Pyramid

Research Article| March 01 1978 Building Cheops' Pyramid John Fitchen John Fitchen Search for other works by this author on: This Site PubMed Google Scholar Journal of the Society of Architectural Historians (1978) 37 (1): 3–12. https://doi.org/10.2307/989311 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation John Fitchen; Building Cheops' Pyramid. Journal of the Society of Architectural Historians 1 March 1978; 37 (1): 3–12. doi: https://doi.org/10.2307/989311 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentJournal of the Society of Architectural Historians Search This content is only available via PDF. Copyright 1978 The Society of Architectural Historians Article PDF first page preview Close Modal You do not currently have access to this content.

Parallelisation Of The SDEM DistinctElement Stress Analysis Code

The SDEM code models systems of interacting blocks of rock using the distinct element (DE) method. The DE method represents these systems as discontinuums with each block acting under Newton's Laws of Motion. The data structures associated with the DE method are comprised largely of linked lists which make the task of obtaining performance gains through vectorisation difficult. The systems, however, are comprised of thousands of blocks and there is the potential of performing block interaction calculations in parallel. This paper details the analysis and refinement steps used in implementing a parallel version of the SDEM. Experience has shown that the gains due to automatic annotation of the original FORTRAN source were limited but that with a modest amount of effort critical data dependencies may be resolved. Satisfactory gains may then be obtained with additional manual annotation of the source. The paper details the procedures used and presents results for Cray Research multiprocessors. The results show that although gains due to vectorisation are limited, the gains due to the parallel implementation are quite satisfactory.

Integration of surveys

Abstract HISTORICAL The rapid initial settlement in this State caused the haphazard occupation of land and issue of title. In 1820 Commissioner Bigge found that 324,251 acres had been granted but thousands of blocks in the country and nearly four-fifths of the houses in Parramatta and Sydney were held without title. The settlers had preceded the surveyors. Through lapse of control and sheer neglect, the survey and land branches of the Government had been allowed to run down into a state of chaos.