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Author(s):  
Min Fang

At present, the hotel resource retrieval algorithm has the problem of low retrieval efficiency, low accuracy, low security and high energy consumption, and this study proposes a large scale hotel resource retrieval algorithm based on characteristic threshold extraction. In the large-scale hotel resource data, the mass sequence is decomposed into periodic component, trend component, random error component and burst component. Different components are extracted, the singular point detection is realized by the extraction results, and the abnormal data in the hotel resource data are obtained. Based on the attribute of hotel resource data, the data similarity is processed with variable window, the total similarity of data is obtained, and the abnormal detection of redundant resource data is realized. The abnormal data detection results and redundant data detection results are substituted into the space-time filter, and the data processing is completed. The retrieval problem is identified, and the data processing results are replaced in the hotel resource retrieval based on the characteristic threshold extraction to achieve the normalization of data source and rule knowledge. The characteristic threshold and retrieval strategy are determined, and data fusion reasoning is carried out. After repeated iteration, effective solutions are obtained. The effective solution is fused to get the best retrieval result. Experimental results showed that the algorithm has higher retrieval accuracy, efficiency and security coefficient, and the average search energy consumption is 56n J/bit.


Poljoprivreda ◽  
2021 ◽  
Vol 27 (2) ◽  
pp. 75-83
Author(s):  
Sanja Jelić Milković ◽  
Ružica Lončarić ◽  
Krunoslav Zmaić ◽  
David Kranjac ◽  
Maurizio Canavari

Until now, no research has been carried out in Croatia into consumer preferences for a particular agricultural and food product by a choice experiment. Therefore, little data are available about Croatian consumers' preferences for social concerns (sustainability, biodiversity, rural development and animal welfare) with regard to the consumer choice and behavior favoring local pig breeds, in this case the Black Slavonian Pig breed. A survey was the method used to collect the data, and a survey questionnaire was used as an instrument. The survey was performed on a sample of n = 100 Croatian consumers surveyed online using a hypothetical choice experiment. The data were analyzed using the three logit models: a multinomial logit model (MNL), random parameter logit (RPL), and an error component random parameter logit model (RPL-EC) in order to examine the consumers’ heterogeneous preferences for fresh ham meat of the Black Slavonian Pig. The results suggest that the Croatian consumers appreciated a darker red fresh pork meat than the one obtained from the Black Slavonian Pig reared outdoors and semi-outdoor. They also prefer a fresh meat bearing a geographical information label, such as the continental Croatia and continental Croatia + PDO, to a fresh meat without a label.


Robotica ◽  
2021 ◽  
pp. 1-16
Author(s):  
Jiaxuan Li ◽  
Yongjie Zhao ◽  
Qingqiong Tang ◽  
Wei Sun ◽  
Feifei Yuan ◽  
...  

Abstract This paper develops the conceptual design and error analysis of a cable-driven parallel robot (CDPR). The earlier error analysis of CDPRs generally regarded the cable around the pulley as a center point and neglected the radius of the pulleys. In this paper, the conceptual design of a CDPR with pulleys on its base platform is performed, and an error mapping model considering the influence of radius of the pulleys for the CDPR is established through kinematics analysis and a full matrix complete differential method. Monte Carlo simulation is adopted to deal with the sensitivity analysis, which can directly describe the contribution of each error component to the total orientation error of the CDPR by virtue of the error modeling. The results show that the sensitivity coefficients of pulleys’ geometric errors and geometric errors of the cables are relatively larger, which confirms that the cable length errors and pulleys’ geometric errors should be given higher priority in design and processing.


2021 ◽  
Vol 2096 (1) ◽  
pp. 012066
Author(s):  
N A Ishinbaev ◽  
A N Krasnov ◽  
M Yu Prakhova ◽  
Yu V Novikova

Abstract Various measurements in wells are quite challenging due to the specific measurement conditions. There are some additional requirements for measurement systems, in particular, space restrictions. Therefore, measuring several parameters with a single sensor is rather important. The paper discusses a measurement system that allows measuring temperature and pressure with a single sensor – an SOS-based strain gauge pressure transducer with a bridge or half-bridge circuit. In this case, pressure and temperature measuring channels are calibrated individually, which creates another error component. The numerical simulation of calibration described herein shows that regardless of the sensor circuit, the voltage uncertainty band of both measuring channels is characterized by a reduced error of 0.03 % with a confidence probability P = 0.9.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Harish Kumar Singla ◽  
Anand Prakash

PurposeThe purpose of the study is to examine the value-based performance of firms in construction sector in India using Tobin's Q and Market Capitalization (MCAP) and then determine their significant financial drivers.Design/methodology/approachThe study is based on data from 87 firms engaged in infrastructure, real estate, industrial construction and allied areas in India over a study period of 10 years. Three distinct forms of panel regression models have been developed using Tobin's Q and MCAP as dependent variables. The models developed are using Baltagi's (1981) Error Component 2SLS, Varadharajan-Krishnakumar's (1987) Generalized 2SLS and Arellano – Bower/Blundell – Bond's (1991) dynamic panel.FindingsThe study found that MCAP is a better suited value-based performance measure for construction sector firms in India. The study further reports that the age of the firm, profit after tax, investment in research and development, dividends, leverage and net fixed asset are significant positive drivers, whereas cash flow is a significant negative driver.Research limitations/implicationsThe study is limited to a geographic location; therefore, the findings of this study cannot be generalized.Practical implicationsAs MCAP is a better suited value-based performance measure of a firm in the construction sector, managers should focus on improving profitability, higher research and development activities, higher dividends and higher expenditures on net fixed assets for improvement.Originality/valueThis is an original attempt to examine the value-based performance of firms in the construction sector in India using Tobin's Q and MCAP.


2021 ◽  
Vol 11 (19) ◽  
pp. 9002
Author(s):  
Qiang Yang ◽  
Hongkun Ma ◽  
Jiaocheng Ma ◽  
Zhili Sun ◽  
Cuiling Li

Kinematic accuracy is a crucial indicator for evaluating the performance of mechanisms. Low-mobility parallel mechanisms are examples of parallel robots that have been successfully employed in many industrial fields. Previous studies analyzing the kinematic accuracy analysis of parallel mechanisms typically ignore the randomness of each component of input error, leading to imprecise conclusions. In this paper, we use homogeneous transforms to develop the inverse kinematics models of an improved Delta parallel mechanism. Based on the inverse kinematics and the first-order Taylor approximation, a model is presented considering errors from the kinematic parameters describing the mechanism’s geometry, clearance errors associated with revolute joints and driving errors associated with actuators. The response surface method is employed to build an explicit limit state function for describing position errors of the end-effector in the combined direction. As a result, a mathematical model of kinematic reliability of the improved Delta mechanism is derived considering the randomness of every input error component. And then, reliability sensitivity of the improved Delta parallel mechanism is analyzed, and the influences of the randomness of each input error component on the kinematic reliability of the mechanism are quantitatively calculated. The kinematic reliability and proposed sensitivity analysis provide a theoretical reference for the synthesis and optimum design of parallel mechanisms for kinematic accuracy.


Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5626
Author(s):  
Seon-Ik Hwang ◽  
Seong-Hyeon Cho ◽  
Jun-Hyung Jung ◽  
Jang-Mok Kim

In recent years, electric propulsion systems have become widely, used and these systems have strict limits in volume and weight. Therefore, it is necessary to reduce the weight of the inverter-motor drive system. In a typical inverter-motor drive system, at least phase current sensors are required. In order to reduce the number of phase current sensors, this paper proposes a method for measuring phase current using DC link current sensors in a inverter-motor drive system. Two phase currents per inverter-motor system are measured during one period of the switching frequency using the pulse width modulation (PWM) shift method. However, since the measured phase current contains an error component in the average current, the error component was compensated for in order to obtain a current similar to the actual phase current by using the slope and dwell time of the phase current. The effectiveness of the proposed method is verified through experiments.


2021 ◽  
Vol 24 (3) ◽  
pp. 110-127
Author(s):  
Gabriela Trnková ◽  
Zdeňka Žáková Kroupová

This paper is focused on the investigation of the competitiveness drivers, namely technical and scale efficiency and technological change, and their relation to the profitability of the Czech food processing companies in the period 2016–2019. This investigation is based on the stochastic frontier modelling of an input distance function in the specification of the four-error-component model. The model is estimated with a multi-step procedure employing the generalized method of moments estimator addressing the potential endogeneity of netputs, and panel data gained from the Bisnode Albertina database. The results revealed (evaluated on the sample mean) that investigated food processing sectors were scale efficient in the analysed period, however, their production technologies exhibited prevailing technological regress. Moreover, the room for almost 17% cost reduction by the technical efficiency improvements was found out in all investigated sectors. Although inter-sectoral differences exist in the scale efficiency, technological change and technical efficiency dynamics, to increase the productivity and competitiveness of food processing companies, it is generally appropriate to focus on technical efficiency and technological change improvements. Both these competitiveness drivers connected with the cost reduction and minimizing of wastage of inputs are achievable through innovations. In general, the basic source of their financing is profit, the achievement of which is supported by cost minimization. However, it was found that sub-sectors, which are linked to sensitive sectors of agricultural production – that means sectors with the lowest national self-sufficiency, the highest level of imports and thus strong cost reduction pressure – have problem to translate the ability to produce efficiently into profitability. Although these food sectors, which have been also facing strong competition for a long time, which leads to significant pressure to reduce costs, achieved the highest technical efficiency, their profitability was lowest from the investigated sectors.


Agriculture ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 835
Author(s):  
Lukáš Čechura ◽  
Zdeňka Žáková Kroupová ◽  
Irena Benešová

The study aims to explore the sources of competitiveness of dairy producers before and after the abolition of milk quotas in selected EU member states. The investigation is based on the stochastic frontier modelling of an input distance function in the specification of the four-error-component model. The model is estimated with a multistep procedure employing the generalized method of moments estimator, addressing the potential endogeneity of netputs, and panel data gained from the FADN database. The results revealed that total factor productivity experienced an increasing trend in the majority of the analysed countries. Since the main driver of productivity growth was found to be the scale effect, our findings support the hypothesis that abolishing milk quotas has a positive effect.


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