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The purpose of this paper is to examine the reduction of crop yield uncertainty using rainfall index insurances. The insurance payouts are determined by a transparent rainfall index rather than actual crop yield of any producer, thereby circumventing problems of adverse selection and moral hazard. The authors consider insurances on rainfall indexes of various months and derive an optimal insurance portfolio that minimizes the income variance for a crop producer.

Various regression models are considered to relate crop yield to monthly mean temperature and monthly cumulative precipitation. A bootstrapping method is used to simulate weather indexes and corn yield in a future year with the correlation between precipitation and temperature incorporated. Based on the simulated scenarios, the optimal insurance portfolio that minimizes the income variance for a crop producer is obtained. In addition, the impact of correlation between temperature and precipitation, availability of temperature index insurance and geographical basis risk on the effectiveness of rainfall index insurance is examined.

The authors illustrate the approach with the corn yield in Illinois east crop reporting district and weather data of a city in the same district. The analysis shows that corn yield in this district is negatively influenced by excessive precipitation in May and drought in June–August. Rainfall index insurance portfolio can reduce the income variance by up to 51.84 percent. Failing to incorporate the correlation between temperature and precipitation decreases variance reduction by 11.6 percent. The presence of geographical basis risk decreases variance reduction by a striking 24.11 percent. Allowing for the purchase of both rainfall and temperature index insurances increases variance reduction by 13.67 percent.

By including precipitation shortfall into explanatory variables, the extended crop yield model explains more fluctuation in crop yield than existing models. The authors use a bootstrapping method instead of complex parametric models to simulate weather indexes and crop yield for a future year and assess the effectiveness of rainfall index insurance. The optimal insurance portfolio obtained provides insights on the practical development of rainfall insurance for corn producers, from the selection of triggering index to the demand of the insurance.

Fast obstacle avoidance path planning is a challenging task for multijoint robots navigating through cluttered workspaces. This paper aims to address this issue by proposing an improved path-planning method based on the distorted space (DS) method, specifically designed for high-dimensional complex environments.

The proposed method, termed topology-preserved distorted space (TP-DS) method, mitigates the limitations of the original DS method by preserving space topology through elastic deformation. By applying distinct spring constants, the TP-DS autonomously shrinks obstacles to microscopic areas within the configuration space, maintaining consistent topology. This enhancement extends the application scope of the DS method to handle complex environments effectively.

Comparative analysis demonstrates that the proposed TP-DS method outperforms traditional methods regarding planning efficiency. Successful obstacle avoidance tasks in the cluttered workspace validate its applicability on a physical 6-DOF manipulator, highlighting its potential for industrial implementations.

The novel TP-DS method generates a topology-preserved collision-free space by leveraging elastic deformation and shows significant capability and efficiency in planning obstacle-avoidance paths in complex application scenarios.

The purpose of this paper is to summarize the research of construction conflict from 1991 to 2020 and propose research directions for future scholarly work. During the recent decades, it is widely accepted that construction conflict is inevitable, and conflict management has become an important component of project management. However, few works were done to map the global study in this field, there is limited review that evaluates the current stage of construction conflict research.

This study adopted a holistic literature review approach that incorporates bibliometric search and scientometric analysis. A total of 698 bibliographic records from the Web of Science core collection database were collected for the scientometric analysis. CiteSpace5.7 was adopted for the science mapping purpose in this study.

Through co-authorship analysis, co-word analysis and co-citation analysis, influential scholars and journals are identified. Several research trends are highlighted according to the scientometric analyses of the construction conflict topics. For example, the application of simulation and algorithms to the study of construction conflict management systems.

Construction is a resource-intensive, multi-participant and multi-targeted industry. Conflicts always exist in the whole life cycle of construction projects, it is important for industry practitioners to be updated of the latest movement and progress of the academic research.

This study contributed to the body of knowledge in construction conflict and bridge the research gap in the thorough review of previous research work.

Considering the industrial site environment and installation requirements, the straight-beam ultrasound probe with easy installation and good coupling agent adaptability is adopted to replace the traditional water immersion focusing probe for film thickness measurement in cylindrical roller bearings. The straight-beam probe has a large echo receiving range, which will result in measurement regions overlapping and bring about large measurement errors. In this paper, an improved measurement method for film thickness of cylindrical roller bearing with the straight-beam probe is developed.

An improved method is proposed to enhance the spatial resolution of the straight-beam probe. By introducing a correction coefficient based on the percentage of the effective measurement area, the method improves the measuring accuracy successfully.

The experimental results demonstrate that the lubricant-film thickness can be measured to reasonable accuracy by this method and have a better agreement with the theoretical film thickness solutions.

This paper used analytical method and model that is helpful for the improvement of the spatial resolution, which has great influence on the measuring accuracy, is mainly determined by the echo reflection area size of the ultrasound transducer.

This paper aims to focus on the variable stick force-displacement (SFD) gradience in the active side stick (ASS) servo system for the civil aircraft.

The problem of variable SFD gradience was introduced first, followed by the analysis of its impact on the ASS servo system. To solve this problem, a linear-parameter-varying (LPV) control approach was suggested to process the variable gradience of the SFD. A H_∞ robust control method was proposed to deal with the external disturbance.

To validate the algorithm performance, a linear time-variant system was calculated to be used to worst cases and the SFD gradience was set to linear and non-linear variation to test the algorithm, and some typical examples of pitch angle and side-slip angle tracking control for a large civil aircraft were also used to verify the algorithm. The results showed that the LPV control method had less settling time and less steady tracking errors than H_∞ control, even in the variable SFD case.

This paper presented an ASS servo system using the LPV control method to solve the problem caused by the variable SFD gradience. The motor torque command was calculated by pressure and position feedback without additional hardware support. It was more useful for the electronic hydraulic servo actuator.

This was the research paper that analyzed the impact of the variable SFD gradience in the ASS servo system and presented an LPV control method to solve it. It was applicable for the SFD gradience changing in the linear and non-linear cases.

The application of weather derivatives in hedging crop yield risk is gaining more interest. However, the further development of weather derivatives – particularly exchange-traded – in the agricultural sector has been impeded by concerns over their hedging performance. The purpose of this paper is to develop a new framework to derive the optimal hedging strategy and evaluate hedging effectiveness.

This framework incorporates a stochastic temperature model, a crop yield model, a risk-neutral pricing method and a profit optimization procedure. Based on a large number of simulated scenarios, the authors study crop yield hedge for a future year. The authors allow the hedger to choose from different types of exchange-traded weather derivatives, and examine the impact of various factors on the optimal hedging strategy.

The analysis shows that hedging objective, pricing method and geographical location of the hedged exposure all play important roles in choosing the best hedging strategy and assessing hedging effectiveness.

This framework is forward-looking, because it focusses on the crop yield hedge for a future year rather than on the historical hedging effectiveness often studied in literature. It utilizes the most up-to-date information related to temperature and crop yield, and hence produces a hedging strategy which is more relevant to the year under consideration.

The aim of this research is to enable web‐based tracking and guiding by integrating location‐awareness with the Worldwide Web so that the users can use various location‐based applications without installing extra software.

The concept of web‐based tracking and guiding is introduced and the relevant issues are discussed regarding location‐aware web systems, location determination, location‐dependent content query and personalized presentation. The framework of the web‐based tracking and guiding system – the Web‐Based Guide is proposed, and its prototypical implementation is presented. The main design principles are making use of existing web technologies, making use of available and cheap devices, general‐purpose and lightweight client‐side, and good scalability.

The paper presents the general‐purpose and modular framework of the Web‐Based Guide, which consists of the Location Server, the Content Server, the Guiding Web Server and the clients which are standard web browsers extended with the Location Control. With such a framework, location‐based applications can offer the services on the web.

The performance of the system should be evaluated and improved, such as the number of the concurrent sessions that the system can sustain, and the workload on the system when in the tracking mode.

The paper proposes a framework for personalized tracking and guiding systems on the web, which can be used in campuses, museums, national parks and so on.

This paper aims to explore how the presence of an audit committee is associated with other corporate governance mechanisms, i.e. board structure, ownership structure and quality of external audit. The present study evaluated whether the presence of the audit committee complements or substitutes other governance mechanisms in Palestinian companies. Moreover, the effect of investment opportunities on the relationship between the formation of the audit committee and the quality of the auditor was addressed.

The association between the formation of the audit committee and other governance variables was modelled as a binary logistic model. The sample comprising 44 firms listed on Palestine exchange for the period between 2013 and 2017, amounting to 220 firm-year observations.

Based on the investigation, the results have indicated that board independence, the distinction between the chairman and chief executive officer function, ownership concentration and audit quality enhance the chance of audit committee formation, implying complementary effect. Contrastingly, board size and board ownership serve as a substitute to audit committee formation. It has also been found that investment opportunities act as an effective moderating factor that strengthens the relationship between audit quality and the formation of the audit committee.

The study provides valuable insight into the interaction between multiple corporate governance mechanisms within the economy of Palestine where the external uncertainty is high and investment opportunities are constrained by the decisions of the occupying authority. The findings may help regulators and policymakers in Palestine alongside those of other countries with similar environmental features to revise and update their corporate governance codes to ensure that the best control can be achieved, subsequently attracting more foreign and domestic investments.

Research on grey systems is becoming more sophisticated, and grey relational and prediction analyses are receiving close review worldwide. Particularly, the application of grey systems in marine economics is gaining importance. The purpose of this paper is to summarize and review literature on grey models, providing new directions in their application in the marine economy.

This paper organized seminal studies on grey systems published by Chinese core journal database – CNKI, Web of Science and Elsevier from 1982 to 2018. After searching the aforementioned database for the said duration, the authors used the CiteSpace visualization tools to analyze them.

The authors sorted the studies according to their countries/regions, institutions, keywords and categories using the CiteSpace tool; analyzed current research characteristics on grey models; and discussed their possible applications in marine businesses, economy, scientific research and education, marine environment and disasters. Finally, the authors pointed out the development trend of grey models.

Although researches are combining grey theory with fractals, neural networks, fuzzy theory and other methods, the applications, in terms of scope, have still not met the demand. With the increasingly in-depth research in marine economics and management, international marine economic research has entered a new period of development. Grey theory will certainly attract scholars’ attention, and its role in marine economy and management will gain considerable significance.

Information carriers (including mass media and We-Media) play important roles in information diffusion on social networks. The purpose of this paper is to investigate changes in the dissemination of information combing with data analysis.

This work analyzed nearly 200 years of coverage of different information carriers during different periods of human society, from the period of only mouth-to-mouth communication to the period of modern society. Information diffusion models are built to illustrate how the information dynamic changes with time and combined box office data of several movies to predict the process of information diffusion. In addition, a metric is defined to identify which information would become news in the future.

Results show that with the development of information carriers, information spreads faster and wider nowadays. The correctness of the metric proposed has been validated.

The structure of social networks influences the dissemination of information. There are an enormous number of factors that influence the formation of hotspots.

The results and conclusion of this work will benefit by predicting the evolution of information carriers. The metric proposed will aid in searching hot news in the future.

This work may shed some light on a better understanding of information diffusion, spreading not only on social networks but also on the carriers used for the information spreading.