ISSN 0253-2778

CN 34-1054/N

2021 Vol. 51, No. 7

Display Method:
A novel hybrid solar preheating intercooled gas turbine based on linear Fresnel reflector
Yousef N. DABWAN, PEI Gang, Trevor Hocksun KWAN, ZHAO Bing
2021, 51(7): 505-520. doi: 10.52396/JUST-2021-0065
In this study, a new hybrid Solar Preheating Intercooled Gas Turbine (SPIcGT) is originally introduced, in which a linear Fresnel solar field used for preheating the compressed air before entering the combustor.The solar Preheating Gas Turbine (SPGT) has been used as a reference gas turbine cycle. Eight performance indicators have been used in the analysis under Guangzhou (China) weather data. The study reveals that the SPIcGT is superior to the SPGT system as it is capable of boosting the fuel-based efficiency by 19.5% versus 0.26% for the SPGT system.The SPIcGT has lower specific fuel consumption (about 7017 kJ/kWh) compared with the 10358 kJ/kWh for SPGT.Meanwhile,the solar integration of the linear Fresnel solar field into an intercooled gas turbine cycle is more economical than the solar integration with the conventional gas turbine cycle. The levelized electricity cost of 4.34 USȻ/kWh was achieved for SPIcGT which is lower than 5.15% for SPGT. Moreover,the fuel consumption and CO2 emissions can be reduced greatly (about 19.3 %) by integrating the linear Fresnel solar field with the intercooled gas turbine.
Multi-valued indicators in DEA in the presence of undesirable outputs: A goal-directed approach
2021, 51(7): 521-541. doi: 10.52396/JUST-2021-0092
The data envelopment analysis (DEA) is an important data-driven method for the performance evaluation and performance improvement of a set of peer decision making units (DMUs), involving multiple inputs and multiple outputs which are identified as performance indicators. However, some performance indicators, unlike conventional DEA models with one single value, may have more than one value because of different definitions or measurement standards referring to multi-valued indicators. In addition, the performance indicators reflect the current status of DMUs, which ignore the goals of decision-makers. We first propose two modified slacks-based DEA models to deal with multi-valued indicators and provide the Pareto-optimal solution in two common decision-making scenarios, namely the decentralized and centralized decision-making cases. Furthermore, we extend the models by incorporating with the goals of decision-makers to help the DMUs improve their performance and get close to the goals of decision-makers as much as possible. The slacks-based approaches and integration of goals enhance the discriminability of the models to DMUs and provide more practical improvement for some indicators. A case study of 22 cities in the Yangtze River delta region in China is used to illustrate the effectiveness and practicality of our proposed models.
Effects of rural tourism information quality in social media on tourists' travel intention
Kong Bingxian, Shi Xiao, Yang Feng
2021, 51(7): 542-561. doi: 10.52396/JUST-2021-0111
Nowadays, the tourism industry is characterized by ever-increasing competition, and social media is the main way we get information in the information age. As an important branch of tourism, rural tourism industry is of great significance to economy and culture in China. Since rural tourism is an important part of tourism development and the current research on rural tourism is still insufficient, this paper puts forward the following two research questions. First, which quality of rural tourism information in social media will affect tourists' perception of destination image? Second, whether tourists' perception of the destination image will affect tourists' rural tourism intention?Based on the previous literature, we select relevant concepts and items about information quality, the destination image and travel intention to form a questionnaire to investigate people's travel behavior.A total of 177 respondents completed our survey, and it has been proved that there are significant positive correlations among rural tourism information quality, destination images and travel intention. The results based on empirical analysis indicate that the qualities are positively relating with the perception of the destination image are informativeness, value-added, amount of information, accessibility and source credibility, and have a significant impact on travel intention eventually. This study not only examines the role of rural tourism information quality in social media on tourists' travel intention from the theoretical perspective,but also proposes a marketing strategies for governments and practitioners of rural tourism to attract more tourists by improving the information quality in social media from the practical implications.
An efficient multi-user multi-keyword fuzzy search scheme over encrypted cloud storage
Ling Huaze, Xue Kaiping, Wei David S.L., Li Ruidong
2021, 51(7): 562-576. doi: 10.52396/JUST-2021-0071
As more and more enterprises and individuals choose to outsource their encrypted private data to the cloud, Searchable Encryption (SE), which solves the issue of keyword-searching over encrypted data, is becoming much more important. To overcome typos and semantic diversity existing in query requests, fuzzy search is introduced to achieve a misspelling-tolerate search-supported encryption scheme. However, current schemes of fuzzy search over encrypted data not only bring in high computing and communication overhead in multi-user scenarios but also are unable to cover all kinds of error types under the premise of an effective accuracy. In this paper, we thus propose a multi-user multi-keyword fuzzy searchable encryption scheme. Specifically, we introduce the permuterm index to support multi-keyword wildcard search which can solve more kinds of misspelling with a higher degree of correctness. Moreover, by letting the cloud server re-encrypt indexes user encrypt, our scheme supports unshared-key multi-user fuzzy search, reducing users' computing overhead effectively and improving the level of privacy-preserving. The results of experiments demonstrate that, compared with existing schemes, our scheme not only has a better accuracy rate, but also supports more varieties of misspelling keyword search with acceptable computational overhead.