Multiple Workers Research Articles

Firefly algorithm with multiple workers for the power system unit commitment problem

This paper proposes an improved firefly (FF) algorithm with multiple workers for solving the unit commitment (UC) problem of power systems. The UC problem is a combinatorial optimization problem that can be posed as minimizing a quadratic objective function under system and unit constraints. Nowadays, highly developed computer systems are available in plenty, and proper utilization of these systems will reduce the time and complexity of combinatorial optimization problems with large numbers of generating units. Here, multiple workers are assigned to solve a UC problem as well as the subproblem, namely economic dispatch (ED) in distributed memory models. The proposed method incorporates a group search in a FF algorithm and thereby a global search is attained through the local search performed by the individual workers, which fine tune the search space in achieving the final solution. The execution time taken by the processor and the solution obtained with respect to the number of processors in a cluster are thoroughly discussed for different test systems. The methodology is validated on a 100 unit system, an IEEE 118 bus system, and a practical Taiwan 38 bus power system and the results are compared with the available literature.

Determining Underground Mining Work Postures Using Motion Capture and Digital Human Modeling.

According to Mine Safety and Health Administration (MSHA) data, during 2008-2012 in the U.S., there were, on average, 65 lost-time accidents per year during routine mining and maintenance activities involving remote-controlled continuous mining machines (CMMs). To address this problem, the National Institute for Occupational Safety and Health (NIOSH) is currently investigating the implementation and integration of existing and emerging technologies in underground mines to provide automated, intelligent proximity detection (iPD) devices on CMMs. One research goal of NIOSH is to enhance the proximity detection system by improving its capability to track and determine identity, position, and posture of multiple workers, and to selectively disable machine functions to keep workers and machine operators safe. Posture of the miner can determine the safe working distance from a CMM by way of the variation in the proximity detection magnetic field. NIOSH collected and analyzed motion capture data and calculated joint angles of the back, hips, and knees from various postures on 12 human subjects. The results of the analysis suggests that lower body postures can be identified by observing the changes in joint angles of the right hip, left hip, right knee, and left knee.

Применение параллельной реализации алгоритма ветвей и границ с использованием MPI для оптимального выбора технологического оборудования

In this paper, we propose a parallel implementation of the branch-and- bound optimization technique on distributed-memory systems using Message Passing Interface (MPI). We employ parallel branch-and-bound to accelerate a real-world example application: optimal selection of production equipment for multi-product batch plants. We describe the master-worker organization of our parallel algorithm: a single master process dispatches a subset of computations to multiple worker processes and gathers computed results from them. For exchanging messages between master and worker we use MPI's point-to-point communication functions. We report experimental results about the speedup and efficiency of our parallel implementation. We observe that the master process may become a bottleneck for the overall application performance if it controls too many workers processes, because of the increasing communication overhead.

English

Aunifiedfiber-to-the-homes (FTTHs) and wireless sensor network (WSN) provides a profitable solution to build up an immaculate ubiquitous-City (U-city). The key objects of actual convergence of FTTH and WSN are less computational intricacy for data packet processing, little installation cost, and good quality of services. In this paper, we familiarise an integrated network structure of multi-optical line terminal (multi-OLT) passive optical network (PON) which can lodge multiple service workers in a single PON. A modified version of interleaved polling algorithm is proposed for scheduling of control messages from multiple OLTs in a single network. We also provide thorough mathematical analysis of cycle time variation, succeeding grant scheduling time, and average packet interruption for both uniform and non-uniform traffic loads generated by each ONU, using fixed service bandwidth provision scheme and limited service bandwidth sharing scheme. We also compare the throughput of the anticipated scheme with existing single-OLT PON for non-uniform traffic load using limited provision bandwidth allocation scheme. The replication results show that the proposed multi-OLT PON system can ropes prevailing bandwidth allocation schemes with better routine than the single-OLT PON in terms of average packet delay, bandwidth consumption, and throughput.

Enhancing adolescents' motivation for treatment in compulsory residential care: A clinical review

Youths in compulsory residential care show a high prevalence of various mental health problems but often lack motivation to engage in therapeutic treatment. Although the self-determination-theory (SDT) and the transtheoretical model of change (TTM) offer a useful framework for treatment motivation, they do not describe which interventions therapists can use to improve treatment motivation in juveniles, nor do they focus specifically on treatment motivation in a compulsory residential care setting. This article provides an overview of opportunities to enhance adolescents' motivation for treatment in compulsory residential care. Results show that in the reviewed literature, increasing autonomy and competence has received relatively little attention compared to relatedness. In addition, results show that treatment motivation can be enhanced in several different ways, ranging from interventions on an individual to an organizational level. This may indicate that enhancing motivation for treatment in a residential setting needs intervention on multiple levels, involving youths, therapists, group workers and parents. Scientific evidence, however, is limited. Regarding the lack of studies that examine the need for autonomy and competence, future studies should focus on these basic needs for motivation.

Distributed Assertion Checking Using Symbolic Execution

Annotating functional correctness properties of code using assertions, in principle, enables systematic checking of code against behavioral properties. In practice however, checking assertions can be costly, especially for complex code annotated with rich behavioral properties. This paper introduces a novel approach for distributing the problem of checking assertions for better scalability. Leveraging that assertions should be side effect free, our approach distributes assertion checking into simpler sub-problems---each focusing on checking one single assertion, so that different assertions are checked in parallel among multiple workers. Furthermore, the sub-problem analysis performed by each worker is guided by the checked assertion to avoid irrelevant path exploration and is prioritized based on the distance towards the checked assertion to provide earlier feedback. A case study shows that our approach can provide a reduction in analysis time required for symbolic execution of Java programs compared to non-distributed approach using the Symbolic PathFinder tool.

HIV/AIDS: A Persistent Health Issue for Women and Children in Mid and Far Western Nepal.

This article reviews the effect of male migration on the spread of HIV infections in mid and far-western Nepal. It explains the link between male mobility and HIV in women and children. Materials were collected by a systematic search of the databases and the websites of national and international agencies. HIV infection amongst male migrants was found to be high. Their risk behaviors such as unprotected sex with multiple partners and sex workers increase the risk of HIV infection. Substance abuse, loneliness, separation from families, peer pressure, long working hours and poor living conditions are factors that promote unsafe sex. Literacy and awareness about HIV is a key measure to decrease the prevalence of the disease and reduce social stigma among people affected. HIV is a major public health issue especially in Nepal with migration playing a major role in its spread. Negligence to sexual health and lack of comprehensive knowledge on the disease among male migrants are the major obstacles that have exacerbated the disease. There is a need for further research on the existing HIV cases affecting women and children of these two regions to get a clear picture of the gravity of the disease.

Variabilidad de la distribución en derivaciones a consulta especializada entre profesionales de un centro de salud

ObjectivesTo determine the distribution in variability of referrals to a specialist by each healthcare worker according to their primary care (PC) centre. To analyze the distribution of the referrals to different specialists. MethodologyThis is a descriptive cross-sectional study conducted in San José Centro PC centre in the city of Zaragoza, with 18,264 inhabitants, where referrals to specialist consultations made by healthcare workers are analyzed. The necessary statistics for the descriptive analysis and for the comparison between multiple workers of the PC were used. For analysis, Chi square and standardized residuals were used. The study includes all referrals made by medical staff of the PC, which consisted of 13 physicians. Referrals cover the period between 1st of January 2010 until 31st December 2010, with data collected through the Management of Primary Care, due to the impossibility of obtaining a computer-based medical history. Indicators were the number of referrals per 100 patients assisted in general practice according to each PC workers and according to each specialty. Results6,345 referrals to different specialists were analyzed. PC centre assisted 74,529 patients with a referral rate of 8.54%. The specialties with a greater demand were ophthalmology (14.4%), dermatology (12.9%), traumatology (7.8%), ENT (7,7%), cardiology (5.8%), gastroenterology (5.1%), A&E (4.7%), neurology (4.7%), urology (4.1%), psychiatry (3.6%), rehabilitation (3.4%) rheumatology (2.8%), endocrinology (2.2%), obstetrics (1.8%), allergology (1.7%), pulmolonogy (1.5%), haematology (0.7%), internal medicine (0.5%), nephrology (0.3%) and geriatric medicine (0.3%). ConclusionsThe study shows great variability of referrals to different specialists by each physician of the PC. In addition, there is an disproportionate variability regarding the frequency of referrals to certain specialists.

Lessons learned from an incident at a cryogenic gas processing facility

In September 2009, a fatal incident occurred in a cryogenic gas processing plant. The investigation of the incident indicated a number of potential issues that may have contributed to or caused the event. These issues include hot work procedures, electrostatic discharge, electrical conduit sealing, convective “breathing” due to multiple vents, equipment age, maintenance, and worker training. The investigation concluded that the fuel for this event was provided by small leaks from the product pipes inside of the cold box; the oxygen was provided by convective “breathing” that occurred due to the presence of two vents from the cold box and the erosion of the flapper valves that were intended to seal these vents; and ignition occurred due to stray currents that resulted from poor hot work procedures, and locating the return lead far from the work location. This article provides an overview of the process and facility, a timeline of events, a summary of the investigative process, and a discussion of the lessons learned from this event. © 2015 American Institute of Chemical Engineers Process Saf Prog 35: 143–148, 2016

Argonaut

Crowdsourced workflows are used in research and industry to solve a variety of tasks. The databases community has used crowd workers in query operators/optimization and for tasks such as entity resolution. Such research utilizes microtasks where crowd workers are asked to answer simple yes/no or multiple choice questions with little training. Typically, microtasks are used with voting algorithms to combine redundant responses from multiple crowd workers to achieve result quality. Microtasks are powerful, but fail in cases where larger context (e.g., domain knowledge) or significant time investment is needed to solve a problem, for example in large-document structured data extraction. In this paper, we consider context-heavy data processing tasks that may require many hours of work, and refer to such tasks as macrotasks. Leveraging the infrastructure and worker pools of existing crowdsourcing platforms, we automate macrotask scheduling, evaluation, and pay scales. A key challenge in macrotask-powered work, however, is evaluating the quality of a worker's output, since ground truth is seldom available and redundancy-based quality control schemes are impractical. We present Argonaut, a framework that improves macrotask powered work quality using a hierarchical review. Argonaut uses a predictive model of worker quality to select trusted workers to perform review, and a separate predictive model of task quality to decide which tasks to review. Finally, Argonaut can identify the ideal trade-off between a single phase of review and multiple phases of review given a constrained review budget in order to maximize overall output quality. We evaluate an industrial use of Argonaut to power a structured data extraction pipeline that has utilized over half a million hours of crowd worker input to complete millions of macrotasks. We show that Argonaut can capture up to 118% more errors than random spot-check reviews in review budget-constrained environments with up to two review layers.

How is Interprofessional Collaboration Applied by Radiation Therapists in the Radiation Therapy Department in British Columbia?

IntroductionInterprofessional collaboration (IPC) is the process when multiple health workers from different professional backgrounds work together with patients to deliver the highest quality of care. IPC can improve communication and knowledge sharing between collaborating professionals and can lead to an increase in efficient patient care. In the radiation therapy department, radiation oncologists, nurses, medical physicists, and radiation therapists are the key professionals involved in the multidisciplinary care team. MethodsAlthough there is ample literature about interprofessional collaboration, very little of it is focused in radiation oncology. Using SurveyMonkey, an online survey was made available to radiation therapists in British Columbia, Canada, for a period of 3 months. In the six British Columbia Cancer Agency centres, champion disseminators assisted in distributing the survey link through e-mail. The questions pertained to the type of IPC, frequency, and modes of collaboration along with radiation therapists' level of satisfaction with collaboration. The number of respondents was 124. ResultsThe results indicate that the top three professionals who radiation therapists collaborate with are radiation oncologists, nurses, and medical physicists, respectively. The frequency of IPC is mostly one to five times in 5 working days. The preferred method of communication with oncologists and physicists is face-to-face interactions or phone calls. The favoured method of communication with nurses is through tasking. E-mail is the least preferred method. ConclusionsBritish Columbia radiation therapists are generally satisfied with IPC. Some suggestions for improvements regarding communication efficiency and respect for others' roles, responsibilities, and professions are made. Overall, results of this study show that IPC generates positive attitudes, teamwork, and a patient-centred model.

Fired for Facebook: Using NLRB guidance to craft appropriate social media policies

Online social media websites have become a major way by which people communicate. This communication can include information deemed relevant to work, in both positive and negative ways. There has been a rise in workers fired for posts they have made on social media. With such terminations come questions of their legality, especially when they involve workers discussing work-related matters and work conditions. These discussions can also include multiple workers chiming in with comments or Facebook ‘likes.’ A number of such termination cases have been brought to the National Labor Relations Board (NLRB) with different rulings made based on the nature of the social media content and the amount and type of response by fellow workers. This article reviews NLRB cases related to social media terminations and common guiding principles that emerge across cases. We give four recommendations to organizations as to how to engage in legal terminations and create social media policies that will pass muster with the NLRB. We discuss general guidelines for crafting social media policies. Finally, we discuss what we still need to know and research in this new and rapidly changing work context.

The Economic Man

This paper questions how economic systems are using knowledge to support economic decision making. Scientific knowledge collected by centralized planners is not the right type of information to base economic decisions on since it does not have the capacity to consider local opportunity factors. These concerns, originally espoused by Frederick Hayek when analyzing the economy as a whole, can be decomposed to focus on individual businesses. A large corporation, encumbered with a traditional vertical organizational structure, typically has an executive management team taking on the role of the centralized planners in Hayek’s model, and is forced to make decisions without the local opportunity knowledge that may be available in their low-level business units. Economic decisions must fundamentally be based on accurate information that considers local opportunities, and must be made rapidly in today’s dynamic market place. To get access to local knowledge from their low-level business units, executive management teams should consider implementing learning organizations with horizontal management structures that encourage collaboration. Companies with centralized organizational structures simply move too slowly to be competitive. The “Economic Man” is an economist’s creation designed by Mr. Hayek to show how unlikely it is that economic decision makers could ever accurately predict future economic conditions. A hypothetical “Economic Man” with “perfect foresight” was described, in essence, to allow readers to visualize the futility of the assumptions underlying our current economic theories. Yet in today’s competitive business environment, perfect foresight is precisely the standard we impose on our executive managers. The perfect knowledge assumption is said to mislead these economic decision makers into a false believe the problem is simpler, from the perspective of the information needed to support such decisions, than it actually is. This results in poor investment decisions by managers that collect the wrong economic data. The division of labor concept notices that complex jobs can be more efficiently completed by a number of workers performing specialized tasks, than by one worker trying to complete the entire job. By dividing up the required skills on complex tasks across multiple workers, they can become specialists and work their assigned area more efficiently. The level of knowledge required to make workers skilled specialists is essential for the division of labor concept to be effective. Further knowledge is required to quantify economic input variables to the extent that decision makers in executive management can accurately predict how the marketplace will unfold and, in so doing, achieve an "economic man" like stature. No matter how we materialize or describe the problem; it seems the effective acquisition and use of knowledge is the correct answer. Peter Drucker relates the economic successes a corporation has with their ability to create “core competencies” that lead to market leadership positions. He begins to abstractly define the type of data that should be collected to help managers of these corporations monitor the strength and relative position of their core competencies. This relates to Mr. Hayek’s concern that managers need accurate, but relevant, information to base their decisions on. Just when things were looking bleak for our hypothetical “Economic Man,” these important steps define feasible types of real time information processing that can support economic decision makers monitoring the strength and position of core competencies. While it’s not quite as good as the perfect foresight imposed on our “Economic Man,” relevant, near real time economic data is a giant leap forward.

An improved multiple flame photometric detector for gas chromatography

An improved multiple flame photometric detector (mFPD) is introduced, based upon interconnecting fluidic channels within a planar stainless steel (SS) plate. Relative to the previous quartz tube mFPD prototype, the SS mFPD provides a 50% reduction in background emission levels, an orthogonal analytical flame, and easier more sensitive operation. As a result, sulfur response in the SS mFPD spans 4 orders of magnitude, yields a minimum detectable limit near 9×10−12gS/s, and has a selectivity approaching 104 over carbon. The device also exhibits exceptionally large resistance to hydrocarbon response quenching. Additionally, the SS mFPD uniquely allows analyte emission monitoring in the multiple worker flames for the first time. The findings suggest that this mode can potentially further improve upon the analytical flame response of sulfur (both linear HSO, and quadratic S2) and also phosphorus. Of note, the latter is nearly 20-fold stronger in S/N in the collective worker flames response and provides 6 orders of linearity with a detection limit of about 2.0×10−13gP/s. Overall, the results indicate that this new SS design notably improves the analytical performance of the mFPD and can provide a versatile and beneficial monitoring tool for gas chromatography.

Multicategory Crowdsourcing Accounting for Variable Task Difficulty, Worker Skill, and Worker Intention

Crowdsourcing allows instant recruitment of workers on the web to annotate image, webpage, or document databases. However, worker unreliability prevents taking a worker’s responses at “face value”. Thus, responses from multiple workers are typically aggregated to more reliably infer ground-truth answers. We study two approaches for crowd aggregation on multicategory answer spaces: stochastic modeling-based and deterministic objective function-based. Our stochastic model for answer generation plausibly captures the interplay between worker skills, intentions, and task difficulties and captures a broad range of worker types. Our deterministic objective-based approach aims to maximize the average aggregate confidence of weighted plurality crowd decision making. In both approaches, we explicitly model the skill and intention of individual workers, which is exploited for improved crowd aggregation. Our methods are applicable in both unsupervised and semi-supervised settings, and also when the batch of tasks is heterogeneous , i.e., from multiple domains, with task-dependent answer spaces. As observed experimentally, the proposed methods can defeat “tyranny of the masses”, i.e., they are especially advantageous when there is an (a priori unknown) minority of skilled workers amongst a large crowd of unskilled (and malicious) workers.

A formal model for intellectual relationships among knowledge workers and knowledge organizations

An academic learning network consists of multiple knowledge organizations and knowledge workers. The intellectual relationships can be derived from the interactions among them. In this paper, we propose a formal model to describe the interactions in an academic learning network and further provide an evaluation process to quantify intellectual relationships. Our approach is also integrated with a realistic social network platform SMNET.

Computer vision techniques for construction safety and health monitoring

For construction safety and health, continuous monitoring of unsafe conditions and action is essential in order to eliminate potential hazards in a timely manner. As a robust and automated means of field observation, computer vision techniques have been applied for the extraction of safety related information from site images and videos, and regarded as effective solutions complementary to current time-consuming and unreliable manual observational practices. Although some research efforts have been directed toward computer vision-based safety and health monitoring, its application in real practice remains premature due to a number of technical issues and research challenges in terms of reliability, accuracy, and applicability. This paper thus reviews previous attempts in construction applications from both technical and practical perspectives in order to understand the current status of computer vision techniques, which in turn suggests the direction of future research in the field of computer vision-based safety and health monitoring. Specifically, this paper categorizes previous studies into three groups—object detection, object tracking, and action recognition—based on types of information required to evaluate unsafe conditions and acts. The results demonstrate that major research challenges include comprehensive scene understanding, varying tracking accuracy by camera position, and action recognition of multiple equipment and workers. In addition, we identified several practical issues including a lack of task-specific and quantifiable metrics to evaluate the extracted information in safety context, technical obstacles due to dynamic conditions at construction sites and privacy issues. These challenges indicate a need for further research in these areas. Accordingly, this paper provides researchers insights into advancing knowledge and techniques for computer vision-based safety and health monitoring, and offers fresh opportunities and considerations to practitioners in understanding and adopting the techniques.

Intra Firm Bargaining and Shapley Values

The paper revisits the problem of wage bargaining between a firm and multiple workers. We show that the Subgame Perfect Equilibrium of the extensive-form game proposed by Stole and Zwiebel (1996a) does not imply a profile of wages and profits that coincides with the Shapley values as claimed in their classic paper. We propose an alternative extensive-form bargaining game, the Rolodex Game, that follows a simple and realistic protocol and that, under some mild restrictions, admits a unique Subgame Perfect Equilibrium generating a profile of wages and profits that are equal to the Shapley values. The vast applied literature that refers to the Stole and Zwiebel game to give a game-theoretic foundation to the use of the Shapley values as the outcome of the bargain between a firm and multiple workers should instead refer to the Rolodex game.

On Periodicity of Cycle Time of a U-shaped Line in Chase Mode

A U-shaped line with multiple machines and workers in chase mode is considered. In this line, several heterogeneous workers deal with all tasks and walks around in the same line. When a worker catches up the front worker, the former has to wait for the latter leaving the machine by finishing the task there. Task times of each task are different among workers because of their experience. In this model, some periodicity on the cycle time is found for one example in Hiraiwa and Nakade (2009). In this paper, the periodicity of cycle time of a U-shaped line in chase mode is more deeply discussed. It is shown that if there are just two workers then there is no periodicity of cycle time. Examples for three or more worker cases show that the order of workers on the line sometimes highly influences on the length and periodicity of cycle time. By changing the task time of some worker, many types of periodicity are found.

Grandma Makes Granola

SummaryIn introductory calculus, most optimization problems begin with a continuous function. Departing from this trend, we describe a plausible micro-economic scenario with a discontinuous cost function. The case of multiple workers requires a more refined analysis than simply taking a derivative.