Tong Lv, Shi Lefeng and Weijun He
A vital job for one sharing business is dynamically dispatching shared items to balance the demand-supply of different sharing points in one sharing network. In order to construct…
Abstract
Purpose
A vital job for one sharing business is dynamically dispatching shared items to balance the demand-supply of different sharing points in one sharing network. In order to construct a highly efficient dispatch strategy, this paper proposes a new dispatching algorithm based on the findings of sharing network characteristics.
Design/methodology/approach
To that end, in this paper, the profit-changing process of single sharing points is modeled and analyzed first. And then, the characteristics of the whole sharing network are investigated. Subsequently, some interesting propositions are obtained, based on which an algorithm (named the Two-step random forest reinforcement learning algorithm) is proposed.
Findings
The authors discover that the sharing points of a common sharing network could be categorized into 6 types according to their profit dynamics; a sharing network that is made up of various combinations of sharing stations would exhibit distinct profit characteristics. Accounting for the characteristics, a specific method for guiding the dynamic dispatch of shared products is developed and validated.
Originality/value
Because the suggested method considers the interaction features between sharing points in a sharing network, its computation speeds and the convergence efficacy to the global optimum scheme are better than similar studies. It suits better to the sharing business requiring a higher time-efficiency.
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Abstract
Purpose
The purpose of this paper is to present one type of the architecture for wireless sensor network and to discuss in detail the hardware design of the sink node which can be responsible for transmission data or instructions between sensor nodes and data. Finally, an experiment based on wireless sensor network has proved that the design of sink node is applicable and reliable in monitoring environmental elements such as temperature, humidity, etc.
Design/methodology/approach
A design for the sink node is presented which constants three parts: the power module, the storage/display module and the communication module. Zigbee, GPRS and Ethernet techniques are used on ARM7 microcontroller. The sink node is capable of bridging the user's terminal with sensor nodes for information transmission.
Findings
In this paper, a new method of the power management based on wireless sensor network is proposed to conserve energy. The antenna height is proven to be an important factor to the communicating among nodes. Finally, the paper proposes regular patterns of the deployment for sensor nodes based on the communication range and the sampling range.
Originality/value
The experiment for providing real‐time data on environment monitoring parameters indicates that the system is efficient. The authors believe that the idea and the design presented in the paper may help the research and application of wireless sensor network.
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Gonzalo Maldonado-Guzmán, Jose Arturo Garza-Reyes and Lizeth Itziguery Solano-Romo
Na Lv, Yanling Xu, Jiyong Zhong, Huabin Chen, Jifeng Wang and Shanben Chen
Penetration state is one of the most important factors for judging the quality of a gas tungsten arc welding (GTAW) joint. The purpose of this paper is to identify and classify…
Abstract
Purpose
Penetration state is one of the most important factors for judging the quality of a gas tungsten arc welding (GTAW) joint. The purpose of this paper is to identify and classify the penetration state and welding quality through the features of arc sound signal during robotic GTAW process.
Design/methodology/approach
This paper tried to make a foundation work to achieve on‐line monitoring of penetration state to weld pool through arc sound signal. The statistic features of arc sound under different penetration states like partial penetration, full penetration and excessive penetration were extracted and analysed, and wavelet packet analysis was used to extract frequency energy at different frequency bands. The prediction models were established by artificial neural networks based on different features combination.
Findings
The experiment results demonstrated that each feature in time and frequency domain could react the penetration behaviour, arc sound in different frequency band had different performance at different penetration states and the prediction model established by 23 features in time domain and frequency domain got the best prediction effect to recognize different penetration states and welding quality through arc sound signal.
Originality/value
This paper tried to make a foundation work to achieve identifying penetration state and welding quality through the features of arc sound signal during robotic GTAW process. A total of 23 features in time domain and frequency domain were extracted at different penetration states. And energy at different frequency bands was proved to be an effective factor for identifying different penetration states. Finally, a prediction model built by 23 features was proved to have the best prediction effect of welding quality.
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Yu Feng, Wei Tao, Yiyang Feng, Xiaoqia Yin, Na Lv and Hui Zhao
Although a laser profile sensor (LPS) can be used to measure dimensions, the “shadow region” generally degrades the accuracy and precision of width measurements. The accuracy and…
Abstract
Purpose
Although a laser profile sensor (LPS) can be used to measure dimensions, the “shadow region” generally degrades the accuracy and precision of width measurements. The accuracy and precision of such measurements should be improved.
Design/methodology/approach
In this paper, the authors propose herein a technique that combines high dynamic range (HDR) imaging with logistic fitting. First, a HDR image is composed of several images acquired with different exposure times, which augments the grayscale of the object profile and significantly reduces overexposure. Next, the profile is fit to a logistic function, which provides accurate and precise edge coordinates. Finally, given the edge coordinates, the object width is calculated.
Findings
To verify the stability of this logistic algorithm, the authors simulate different noise conditions and different degrees of incomplete edge data. In addition, the progressiveness of the algorithm is demonstrated by comparing the results with those of other algorithms and with the height measurement. Furthermore, the suitability of the system is verified experimentally.
Research limitations/implications
Because of the limitation of the condition of laboratory, in the experimental section, this paper cannot represent perfectly the industrial situation. It makes this section limited in demonstration.
Originality/value
In this paper, the results show that the measurement accuracy and precision of the width is improved and exceeds that of the height measurement. The proposed HDR imaging method with logistic fitting may be applied to LPS width measurements, which should significantly aid the development of LPSs.
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This paper aims to examine the influence of different self-presentation strategies (cultural, personal and informational posts) and interactivity on luxury brands’ social media…
Abstract
Purpose
This paper aims to examine the influence of different self-presentation strategies (cultural, personal and informational posts) and interactivity on luxury brands’ social media advertising.
Design/methodology/approach
Three pre-tests and a main experiment collected responses from 459 Chinese participants in total.
Findings
Cultural posts significantly influenced brand attitudes, interest and purchase intention, and the effects were mediated by perceived reinforcement of the brand’s social media account. Informational posts added to perceived informativeness of the brand’s social media account, but were more likely to trigger a perception that the brand was conservative and distancing itself from consumers. Interactivity increased perceived closeness and reduced perceived inactiveness and conservativeness of the brand’s social media account and subsequently improved brand attitudes. Perception of brand’s social media accountfully mediated the effects of self-presentation strategies and interactivity on brand attitudes, interest and purchase intention.
Research limitations/implications
Self-presentation transfers desirable brand associations to luxury brands, reinforces brand image, and subsequently influences responses to luxury brands. Interactivity largely influences relational perceptions and brand attitudes.
Practical implications
Curating content about brand heritage and culture creates a social media self-presentation that is effective and influential on consumers. Brand and product information satisfies informational needs. Interactivity maintains customer relationship.
Originality/value
A theoretical model of luxury brands’ advertising was generated from the findings.
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Zhenzhi Xu, Na Lv, Qiang Liu and Hui Zhao
Leading error in line laser weld seam tracking significantly affects tracking accuracy. This paper aims to propose an accurate and reliable compensation method without increasing…
Abstract
Purpose
Leading error in line laser weld seam tracking significantly affects tracking accuracy. This paper aims to propose an accurate and reliable compensation method without increasing system complexity for weld seam tracking to improve tracking precision.
Design/methodology/approach
Based on the line laser seam tracking method, the seam image is simultaneously captured to obtain the angle offset of the seam relative to the sensor direction, which is then combined with the leading distance to calculate the leading error. The two sensing methods use different wavelengths and are captured simultaneously by a color industrial camera. The images of the two different wavelengths can be separated by extracting the RGB components, and the compensated tracking results are obtained after image processing.
Findings
The results of static positioning experiment indicate that the average absolute error in weld seam positioning is reduced to 0.099 mm after compensation. The real-time tracking experiments demonstrate that the proposed method preserves tracking accuracy even with changes in the sensor’s angle of deviation during welding, with the average absolute error being 0.248 mm. This method effectively enhances the precision of line laser weld seam tracking when the sensor exhibits a deviation relative to the welding direction.
Originality/value
By using the dual-sensing and dual-wavelength method for leading error compensation, the method effectively addresses the leading error issue while maintaining the advantages of the line laser seam tracking method.
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Na Lv, Yanling Xu, Zhifen Zhang, Jifeng Wang, Bo Chen and Shanben Chen
The purpose of this paper is to study the relationship between arc sound signal and arc height through arc sound features of GTAW welding, which is aimed at laying foundation work…
Abstract
Purpose
The purpose of this paper is to study the relationship between arc sound signal and arc height through arc sound features of GTAW welding, which is aimed at laying foundation work for monitoring the welding penetration and quality by using the arc sound signal in the future.
Design/methodology/approach
The experiment system is based on GTAW welding with acoustic sensor and signal conditioner on it. The arc sound signal was first processed by wavelet analysis and wavelet packet analysis designed in this research. Then the features of arc sound signal were extracted in time domain, frequency domain, for example, short‐term energy, AMDF, mean strength, log energy, dynamic variation intensity, short‐term zero rate and the frequency features of DCT coefficient, also the wavelet packet coefficient. Finally, a ANN (artificial neural networks) prediction model was built up to recognize different arc height through arc sound signal.
Findings
The statistic features and DCT coefficient can be absolutely used in arc sound signal processing; and these features of arc sound signal can accurately react the modification of arc height during the GTAW welding process.
Originality/value
This paper tries to make a foundation work to achieve monitoring arc length through arc sound signal. A new way to remove high frequency noise of arc sound signal is produced. It proposes some effective statistic features and a new way of frequency analysis to build the prediction model.
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Na Lv, Jiyong Zhong, Jifeng Wang and Shanben Chen
Surface forming control of welding bead is the fundamental study in automated welding. Considering that the vision sensing system cannot extract the height information of weld…
Abstract
Purpose
Surface forming control of welding bead is the fundamental study in automated welding. Considering that the vision sensing system cannot extract the height information of weld pool in pulsed GTAW process, so this paper designed a set of automatic measurement and control technology to achieve real-time arc height control via audio sensing system. The paper aims to discuss these issues.
Design/methodology/approach
The experiment system is based on GTAW welding with acoustic sensor and signal conditioner. A combination denoising method was used to reduce the environmental noise and pulse interference noise. After extracting features of acoustic signal, the relationship between arc height and arc sound pressure was established by linear fitting. Then in order to improve the prediction accuracy of that model, the piecewise linear fitting method was proposed. Finally, arc height linear model of arc sound signal and arc height is divided into two parts and built in two different arc height conditions, which are arc height 3-4 and 4-5-6 mm.
Findings
The combination denoising method was proved to have great effect on reducing the environmental noise and pulse interference noise. The experimental results showed that the prediction accuracy of linear model was not stable in different arc height changing state, like 3-4 and 4-5-6 mm. The maximum error was 0.635588 mm. And the average error of linear model was about 0.580487 mm, and the arc sound signal was accurately enough to meet the requirement for real-time control of arc height in pulse GTAW.
Originality/value
This paper tries to make a foundation work to achieve controlling of depth of welding pool through arc sound signal, then the welding quality control. So a new idea of arc height control based on automatic measuring and processing system through arc sound signal was proposed. A new way to remove environmental noise and pulse interference noise was proposed. The results of this thesis had proved that arc sound signal was an effective features and precisely enough for online arc height monitoring during pulsed GTAW.