Search results

To develop an understanding of communication among agribusiness journals and to examine patterns of citations that allow the measurement and description of the structure of communication flows among those journals in a network.

The data for this study were gathered from the Journal Citation Reports (JCR) published by Thomson Scientific (Philadelphia). The authors conducted a bibliometric analysis, based on an international trade analogy to explain the network of agribusiness journals and how these journals communicate with business and economics journals.

Business and economics journals and, particularly the traditionally major ones, surprisingly were scarcely every used. However, the British Food Journal stood out with 50 citations to marketing and strategic management journals.

There are predominantly four such limitations: only 33 journals were studied, only one 5-year time period was involved, that time period is a few years old and the journal characteristics were derived using data from the “Scopes” and “Information for Authors” text on the website of each journal.

Exchanges of agribusiness knowledge and information among diverse stakeholders (consumers, suppliers and public agencies) in a complex environment require a better understanding of the network of agribusiness journals and their relation to traditional business and economics journals.

Networks of journals facilitate cooperation and interactions to improve developments in the field.

Examining citations from and to the field of agribusiness is interesting and important because knowledge is transferred through networks comprise those who contribute to journals, read them and learn from them, i.e. by “talking” to each other as well as by practitioners who also read and learn from those journals.

The purpose of this paper is to propose a new mixed-integer formulation for the time-dependent multi-skilled resource-constrained project scheduling problem (MSRCPSP/t) considering learning effect. The proposed model extends the basic form of the MSRCPSP by three concepts: workforces have different efficiencies, it is possible for workforces to improve their efficiencies by learning from more efficient workers and the availability of workforces and resource requests of activities are time-dependent. To spread dexterity from more efficient workforces to others, this study has integrated the concept of diffusion maximization in social networks into the proposed model. In this respect, the diffusion of dexterity is formulated based on the linear threshold model for a network of workforces who share common skills. The proposed model is bi-objective, aiming to minimize make-span and total costs of project, simultaneously.

The MSRCPSP is an non-deterministic polynomial-time hard (NP-hard) problem in the strong sense. Therefore, an improved version of the non-dominated sorting genetic algorithm II (IM-NSGA-II) is developed to optimize the make-span and total costs of project, concurrently. For the proposed algorithm, this paper has designed new genetic operators that help to spread dexterity among workforces. To validate the solutions obtained by the IM-NSGA-II, four other evolutionary algorithms – the classical NSGA-II, non-dominated ranked genetic algorithm, Pareto envelope-based selection algorithm II and strength Pareto evolutionary algorithm II – are used. All algorithms are calibrated via the Taguchi method.

Comprehensive numerical tests are conducted to evaluate the performance of the IM-NSGA-II in comparison with the other four methods in terms of convergence, diversity and computational time. The computational results reveal that the IM-NSGA-II outperforms the other methods in terms of most of the metrics. Besides, a sensitivity analysis is implemented to investigate the impact of learning on objective function values. The outputs show the significant impact of learning on objective function values.

The proposed model and algorithm can be used for scheduling activities of small- and large-size real-world projects.

Based on the previous studies reviewed in this paper, one of the research gaps is the MSRCPSP with time-dependent resource capacities and requests. Therefore, this paper proposes a multi-objective model for the MSRCPSP with time-dependent resource profiles. Besides, the evaluation of learning effect on efficiency of workforces has not been studied sufficiently in the literature. In this study, the effect of learning on efficiency of workforces has been considered. In the scarce number of proposed models with learning effect, the researchers have assumed that the efficiency of workforces increases as they spend more time on performing a skill. To the best of the authors’ knowledge, the effect of learning from more efficient co-workers has not been studied in the literature of the RCPSP. Therefore, in this research, the effect of learning from more efficient co-workers has been investigated. In addition, a modified version of the NSGA-II algorithm is developed to solve the model.

The purpose of the present work is to develop a unified mathematical theory of the steady and disturbed motion of a helicopter with particular emphasis on the dynamical aspects of the problem. The helicopter is assumed to undergo arbitrary small disturbances in velocity and angular velocity from a steady rectilinear flight condition, and the rotor forces are calculated as generalized functions of the initial and disturbed velocities. A high degree of accuracy is maintained both in the retention, where necessary, of products of small quantities and in the retention of high powers of µ in the solution of the trim equations. The steady motion of the helicopter is discussed at length as a preliminary to a study of its dynamic stability. Part I deals with the general features underlying helicopter motion. The importance is emphasized of a three‐dimensional approach to the problem, and it is shown that a complete description of steady rectilinear motion demands the use of fifteen equations in eighteen parameters, the solution of which presents no real difficulty. A start is made on the analysis of rotor blade motion, and the geometrical aspects are discussed by means of a system of rotating vectors.

THE work described in this paper is part of a programme concerned with the plastic, creep, and relaxation properties of metals under complex stress systems at elevated temperatures.which is being carried out in the Engineering Division of the N.P.L. It comprises data on the criterion of departure from elastic behaviour, of a low carbon steel over the temperature range 20–550 deg. C, and of an aluminium alloy over the temperature range 20–200 deg. C, and the creep properties under complex stress systems of the low carbon steel at 350 deg. C, and of the aluminium alloy at 150 and 200 deg. C.

The purpose of this paper is to study the effect of credit record overconfidence on the use of alternative financial services (AFSs).

Using data from the 2018 National Financial Capability Study (NFCS), the authors estimate logistic regressions on the use of at least one AFS by adding a credit record confidence variable that captures deviations between self-assessments of credit record management and the number of reported behaviors that would negatively affect aspects of a Fair Isaac Corporation (FICO) score.

The authors find that respondents with credit record overconfidence have over two times higher odds (123.9%) of using AFS than the odds of respondents with financial knowledge overconfidence (46.8%), relative to their reference categories. When compared directly, those with only credit record overconfidence have 32.6% higher odds of using AFS than those with only financial knowledge overconfidence.

The results provide implications for education programs, not only for vulnerable groups at higher risk for AFS use but also for those with cognitive biases, such as credit record overconfidence. Potential solutions include personal financial education that includes debiasing and behavioral techniques for overconfidence.

This paper studies, for the first time, the effect of deviations between actual and perceived credit record management on AFS use.

IN the previous article, the lateral stability of an aircraft was shown to depend upon the roots of a quartic equation in which the coefficients were obtained in terms of the resistance derivatives of the aeroplane. These derivatives were defined in a highly synthetic manner from a mathematical rather than a physical standpoint, so that their meaning is apt to be somewhat obscure. It is likely, however, that the use of symbols like lp is familiar to readers who are not otherwise acquainted with stability nomenclature, since these expressions arc commonly used in other aerodynamic topics such as rolling performance, spinning etc. It is important therefore to correlate the definitions given here with those given elsewhere and to establish their physical meanings.