Search results

Hydroelectric power is widely used because it is environmental friendly, renewable and green. The cavitation is an inevitable phenomenon during the operation of hydro turbine, which is related to the efficiency and service life of the unit. This paper aims to discriminate the phenomenon of the incipient cavitation, prevent the early destruction and avoid the irreversible damage to hydro turbine.

The paper tries to find out the characteristics of cavitation entirely through a variety of features. The method comprises collection of the signals using a hydrophone, acceleration sensor and acoustic emission sensor; analyzing cavitation signal by using the way of wavelet time-frequency, peak factor and power spectral density; and comparing the different wavelet basis for analyzing signals and find the most suitable one.

The analyzed results show that the wavelet basis of morlet is more suitable for the cavitation signals. The hydrophone can distinguish the different operating conditions and discriminate the difference between the phenomenon of incipient cavitation and the other state of cavitation. The results show that when the hydrophone and acceleration sensors are used, the accuracy rate goes up to 75 per cent, which meets the requirements for the detection for incipient cavitation.

This paper focuses on finding the best sensor to discriminate the operating state of incipient cavitation to prevent early destruction.

The effective prediction of crude oil futures prices can provide a reference for relevant enterprises to make production plans and investment decisions. To the nonlinearity, high volatility and uncertainty of the crude oil futures price, a matrixed nonlinear exponential grey Bernoulli model combined with an exponential accumulation generating operator (MNEGBM(1,1)) is proposed in this paper.

First, the original sequence is processed by the exponential accumulation generating operator to weaken its volatility. The nonlinear grey Bernoulli and exponential function models are combined to fit the preprocessed sequence. Then, the parameters in MNEGBM(1,1) are matrixed, so the ternary interval number sequence can be modeled directly. Marine Predators Algorithm (MPA) is chosen to optimize the nonlinear parameters. Finally, the Cramer rule is used to derive the time recursive formula.

The predictive effectiveness of the proposed model is verified by comparing it with five comparison models. Crude oil futures prices in Cushing, OK are predicted and analyzed from 2023/07 to 2023/12. The prediction results show it will gradually decrease over the next six months.

Crude oil futures prices are highly volatile in the short term. The use of grey model for short-term prediction is valuable for research. For the data characteristics of crude oil futures price, this study first proposes an improved model for interval number prediction of crude oil futures prices.

Tourism demand forecasting is vital for the airline industry and tourism sector. Combination forecasting has the advantage of fusing several forecasts to reduce the risk of inappropriate model selection for analyzing decisions. This paper investigated the effects of a time-varying weighting strategy on the performance of linear and nonlinear forecast combinations in the context of tourism.

This study used grey prediction models, which did not require that the available data satisfy statistical assumptions, to generate forecasts. A quality-control technique was applied to determine when to change the combination weights to generate combined forecasts by using linear and nonlinear methods.

The empirical results showed that except for when the Choquet fuzzy integral was used, forecast combination with time-varying weights did not significantly outperform that with fixed weights. The Choquet integral with time-varying weights significantly outperformed that with fixed weights for all model combinations, and had a superior forecasting accuracy to those of other combination methods.

The tourism sector can benefit from the use of the Choquet integral with time-varying weights, by using it to formulate suitable strategies for tourist destinations.

Combining forecasts with time-varying weights may improve the accuracy of the predictions. This study investigated incorporating a time-varying weighting strategy into combination forecasting by using CUSUM. The results verified the effectiveness of the time-varying Choquet integral for tourism forecast combination.

The purpose of this paper is to review the literature that measures the concept of firms' information environment (IE) with focus on the validity of proxies used to measure IE.

The paper reviews the IE literature using theoretically based categories and analyzes the contextual meaning and use of IE proxies. The review is based on a selection of 284 research articles from 51 journals between 2000 and 2018. A total of 37 different proxy measures of IE are found and analyzed with respect to causality based on categories and the use of IE variables as dependent, independent and control variables.

The study indicates that the IE measures are heterogeneous and there is a lack of consensus regarding their use. The different conditions used to study IE explain part, but far from all, of this heterogeneity. Furthermore, we find that the use of IE measures is only briefly discussed or motivated among the studies in the sample. These findings suggest a necessary discussion about causality in the use of IE as dependent, independent or control variables.

This study contains new and significant information on IE and IE proxy measures. It provides an extensive literature review and provides a novel typology to analyze IE.

The purpose of this paper is to investigate the agility of oil and gas value chains in the United Arab Emirates (UAE) and to understand the impact of implementing supply disruption (SD) strategies, outsourcing strategies (OS) and management strategies (MS) on oil and gas value chain agility (VCA). The results can support the oil and gas industry across the UAE to build resilience in the value chain.

The research design consists of a comprehensive literature review, followed by questionnaire-based survey responses of 106 participants and comprehensive statistical analysis, thus validate the developed theoretical framework and contribute to both practical and methodological approaches.

The findings indicate that oil and gas value chain in the UAE has moderate a significant degree of SD, when OS in place that are synchronized with the overall MS. Among the hypotheses developed, two were accepted thus warranting both SD strategies (r=+0.432) and MS (r= +0.457) found to have a positive moderate effect on VCA. The third hypothesis was rejected by revealing OS (r=+0.387) found to have a positive moderate relationship with VCA. Therefore, implementation of all three strategies has a positive moderate effect on the agility of the value chain and, therefore, supports to sustain competitive position.

Some of the limitations of this research include the geographic coverage of the study region and other methodological limitation.

The research provides guidance for oil and gas supply chain managers to better understand the critical factors that impact and determine VCA. The paper also describes relevant strategies that should be taken into consideration by these managers in order to build their agile value chains.

The research contributes to the social dimensions of supply chain sustainability of how resilient is the oil and gas value chain during uncertain conditions, so that it can respond to uncertain changes in order to contribute to corporate social responsibility.

This research is the first of its kind in the UAE region to assess the link between dimensions of agile value chain, OS, SD strategies and MS primarily from the Emirates of Abu Dhabi and Dubai.

The incentive cost of enterprises increases significantly with the rapid growth of the social commerce (SC) market. In this context, enterprises need to develop the optimal strategy to improve incentive effectiveness and reduce cost. Different types of consumers’ responses to incentives bring different values to enterprises. Hence, this paper proposes the social commerce value network (SCVN) to help enterprises study the contributions of different types of consumers to the network.

Based on the graphical evaluation and review technique (GERT), the authors construct the social commerce value GERT (i.e. SCV-GERT) network and design three progressive experiments for estimating the value contributions of “network stage”, “consumer type”, and “resource type” to the SCVN under the same incentives. The authors initialize the SCV-GERT model with consumer data in SC and distinguish the most valuable consumers by adjusting the incentive parameters.

The results show that the SCV-GERT model can well describe the value flow of SCVN. The incentive on forwarding consumers brings the greatest value gain to the SCVN, and social trust contributes the most to forwarding consumers.

Under the guidance of the results, platforms and enterprises in SC can select the optimal type of consumers who bring the maximum network value so as to improve the effectiveness of incentive strategy and reduce marketing costs. A four-level incentive system should be established according to the ranking of the corresponding value gains: forwarding consumers > agent consumers > commenting consumers > potential consumers. Enterprises also need to find ways to improve the social resource investments of consumers participating in SC.

This paper investigates the incentive problem in SC grounded in the SCVN and uses the GERT method to construct the SCV-GERT model, which is the first attempt to introduce GERT into the SC context. This study also makes up for the lack of comparative research on different types of consumers in SC and can provide support for enterprises’ customer relationship management and marketing decisions.

Forecasting tourism demand accurately can help private and public sector formulate strategic planning. Combining forecasting is feasible to improving the forecasting accuracy. This paper aims to apply multiple attribute decision-making (MADM) methods to develop new combination forecasting methods.

Grey relational analysis (GRA) is applied to assess weights for individual constituents, and the Choquet fuzzy integral is employed to nonlinearly synthesize individual forecasts from single grey models, which are not required to follow any statistical property, into a composite forecast.

The empirical results indicate that the proposed method shows the superiority in mean accuracy over the other combination methods considered.

For tourism practitioners who have no experience of using grey prediction, the proposed methods can help them avoid the risk of forecasting failure arising from wrong selection of one single grey model. The experimental results demonstrated the high applicability of the proposed nonadditive combination method for tourism demand forecasting.

By treating both weight assessment and forecast combination as MADM problems in the tourism context, this research investigates the incorporation of MADM methods into combination forecasting by developing weighting schemes with GRA and nonadditive forecast combination with the fuzzy integral.

Consumers' willingness to pay premium (WTPP) for two different types of agricultural brand labels (enterprise and regional), are evaluated through a non-hypothetical Random n-price auction experiment during the online purchase of fresh agricultural products. The purpose of this paper is to evaluate the two WTPP, compare their differences, and explore their sustainability.

Data were collected in July–August 2020 from a sample of 310 consumers in Liaoning Province, China. A nonhypothetical random n-price auction experiment was implemented in a simulated online shopping environment.

The results show that WTPP exists, and WTPP level of regional brand labels is higher than that of enterprise brand labels. Consumers' WTPP is sustainable. Consumers with low WTPP for enterprise brand labels and consumers with high WTPP for regional brand labels have stronger willingness to repurchase.

The results have direct practical implications for developing brand agriculture and encouraging “brand consumption”. The results can provide theoretical reference for policymakers, enlightenment for the development and effective dissemination of agricultural brand labels and important information to e-retailers on how to sale agricultural products with agricultural brand labels.

To the best of the authors' knowledge, no previous study has related WTPP and its sustainability for agricultural brand labels in China. We try to fill a gap in literature on consumers' WTPP for agricultural brand labels. And the authors explore the sustainability of WTPP by analyzing the impact of WTPP on repurchase intention and recommendation intention respectively.

This paper aims to explore the future path of agricultural development in China toward 2060 under the dual carbon goals, so as to inform better policy choices for facilitating agricultural and rural transformation toward the goal of maintaining food security, sustainable income growth and low carbon emission.

This study employs a single-country, multi-sectoral computable general equilibrium model, CHINAGEM model and develops eight illustrative scenarios to simulate the impacts of attaining dual carbon goals on agricultural development in China. Additional two scenarios have also been designed to inform better policy making with the aim to offset the negative impact of the decarbonization schemes through facilitating agricultural technology progress.

Dual carbon goals are projected to impose substantial negative impact on agricultural productions and consumptions in China in the coming four decades. Under the assumption of business as usual, agricultural production will reduce by 0.49–8.94% along with the attainment of carbon neutrality goal by 2060, with the production of cereals and high-value being more severely damaged. To mitigate the adverse impact of the decarbonization schemes, it is believed that fastening technology progress in agriculture is one of the most efficient ways for maintaining domestic food security without harming the dual carbon goals. In particular, if agricultural productivity (particularly, for cereals and high-value products) can be increased by another 1% per year, the production losses caused by carbon emission mitigation will be fully offset. This implies that promoting technology progress is still the best way to facilitate agricultural development and rural transformation in future China.

The paper contributes to the literature in better informing the impact of dual carbon goals on China's agriculture and the effectiveness of technology progress in agriculture on buffering the adverse impact of the decarbonization schemes and promoting agricultural development.

The purpose of this paper is to reveal the knowledge evolution process, research hotspots and future trends in the accessible tourism research literature from 2008 to 2020.

A total of 213 articles on accessible tourism were selected from the core collection database of Web of Science (WoS) and analyzed using CiteSpace.

Over the 13-year period between 2008 and 2020, an increasing number of studies have been published concerning accessible tourism, but the overall base is still small. The research content mainly includes six modules. Among institutions, the University of Technology Sydney has published the largest number of papers. Cooperation among countries involves the USA, the United Kingdom, Australia, Portugal and China. Tourism Management is the leading journal for disseminating research on accessible tourism. Definition of “Accessible tourism” and the different scope of this phenomenon are re-discussed. In recent years, “experience” and “participation” have become the “new favorites” in accessible tourism research, which could reveal insights into future research directions.

The sampling frame was defined in terms of the WoS database and even though this is an important database for global academic information, in the big data era, the authors may have to integrate information from multiple sources to comprehensively reveal and understand knowledge maps. Second, because of the operational constraints of the CiteSpace software, the authors only selected outputs published in peer-reviewed journals, excluding other published works, such as books and conference papers. Finally, because of the language restrictions of the authors, this research is limited to journals published in the English language.

Practically, the results of this study made a conclusion of accessible tourism research so that the researchers can easily know what has currently been done and what future research can do. Tourism managers can also understand the demands and the constraints of tourism for the people who have barriers to travel. They can supply more specific products for the accessible tourism and further promote the construction of barrier-free travel environments.

This paper unifies the literature on senior tourism and people with disabilities tourism, and uses CiteSpace to construct data and network visualizations, including a burst and dynamic analysis for the period covered by the sample. Furthermore, this paper proposed a more diversified accessible tourism.

无障碍旅游：文献计量学研究综述 (2008-2020)

此篇论文目的是通过对2008年到2020年间无障碍旅游研究文献进行科学计量和可视化分析, 展示该领域的知识演变进程、研究热点和未来趋势。

从Web of Science核心合集数据库中经过多次筛选, 挑选出213篇文章, 并利用CiteSpace进行分析。

13年来无障碍旅游的研究文献数量总体呈上升趋势, 但总体基数仍然不大, 研究内容主要包含六个模块。机构中悉尼科技大学的发文量最多。国家间的合作以美国、英国、澳大利亚、葡萄牙和中国为基础。主要发行期刊是Tourism Management。本文还对无障碍旅游的定义和内涵重新进行了思考和讨论。近年来“体验”和“参与”成为了无障碍旅游研究中的“新宠”, 揭示出未来的研究方向。

此篇论文将老年旅游和残障旅游统一起来, 并利用CiteSpace做出清晰的数据和网络展示, 包含了过去13年的突发性和动态性分析。并且, 本文提出了更为广泛和多元的无障碍旅游。

无障碍旅游; 残障旅游; 老年旅游; 文献综述; CiteSpace

文章类型： 研究综述

Turismo accesible: una revisión bibliométrica (2008–2020)

El objetivo de este trabajo es revelar el proceso evolutivo del conocimiento, los puntos críticos de la investigación y las futuras tendencias de la literatura de investigación del turismo accesible del 2008 a 2020.

De la base de datos central de la red científica, se seleccionaron 213 artículos sobre turismo accesible y se analizaron utilizando citespace.

En los 13 años transcurridos entre 2008 y 2020 se han realizado cada vez más publicaciones relacionadas con el turismo accesible, pero la base general sigue siendo pequeña. Las investigaciones incluyen principalmente seis módulos. Entre los institutos, la Universidad Tecnológica de Sídney a publicado el mayor número de investigaciones. La cooperación entre los países incluye a los Estados Unidos, Reino Unido, Australia, Portugal y China. La “Tourism Management” es la principal revista de investigación sobre el turismo accesible. Este artículo rediscute la definición de “turismo accesible” y el diferente alcance de este fenómeno. En los últimos años, la “experiencia” y la “participación” se han convertido en el “nuevo favorito” de las investigaciones sobre el turismo accesible, lo que podría revelar perspectivas con relación a la dirección de futuras investigaciones.

Esta investigación combina la literatura relacionada con el turismo adulto mayor y personas con discapacidad, utiliza citespace para construir los datos y la visualización de la red, incluyendo un análisis dinámico y de ráfagas para el período cubierto por la muestra. Además, este documento propone un turismo accesible más diversificado.

Turismo accesible, Personas con discapacidad, Adulto mayor, Bibliometría, CiteSpace

RevisiÓn de la literatura