Heng Xu, Xuliang Wu and Yatian Liu
This paper aims to theoretically investigate an online company’s optimal decision on its offline expansion strategy. In the past five years, many large online retailers and…
Abstract
Purpose
This paper aims to theoretically investigate an online company’s optimal decision on its offline expansion strategy. In the past five years, many large online retailers and internet-based companies such as Amazon, Google, Alibaba, Tencent and JD.com have expanded their offline market but it was observed that they adopted different expansion strategies. Specifically, some of them expand the offline market by acquiring offline retailers, while some do so by purchasing a portion of offline retailer’s stake. This difference leads to a quite different structure in post-expansion market, having an impact on profit, consumer surplus and social welfare. The goal of this paper is to model such expansion strategies in a general way and complete studies on profits and welfare.
Design/methodology/approach
By constructing a Salop model with two offline retailers and one online company, this paper analyzes the case where the online company can expand its offline market by either acquiring or jointing (e.g. stakeholding) with one offline retailer. The former strategy (named Strategy A) allows the online company to fully control and capture residual claims of the offline retailer. With the adoption of the latter strategy (named Strategy C), on the other hand, the online company can obtain a fixed proportion of its offline partner’s quasi rent. In the price competition, the online company chooses its optimal offline expansion strategy by predicting its profit in the post-expansion market.
Findings
This paper found that the equilibrium crucially depends on the synergy effect due to online–offline integration, and such synergy also influences both consumer and social welfare. This study shows the various conditions on the synergy that affect an online company moves toward offline markets. Accordingly, this finding can assist online companies with or without retailing business to choose an optimal strategy when expanding offline markets. Moreover, by doing some necessary welfare analysis, this study shows that the online company’s offline expansion is not always benefiting consumers nor be socially desirable, which may shed some lights on the possible competition policy in the case where online companies practice in offline expansion.
Originality/value
Different from conventional wisdom in online-offline integration, the theory indicates that the offline expectation of online company may not always benefit consumers nor be socially desirable. Moreover, the findings also shed some lights on the possible competition policy in the case where online companies practice in offline expansion.
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Xuliang Yao, Xiao Han, Yuefeng Liao and Jingfang Wang
This paper aims to better design the resonant tank parameters for LLC resonant converter. And, it is found that under heavy load, the voltage gain is affected by junction…
Abstract
Purpose
This paper aims to better design the resonant tank parameters for LLC resonant converter. And, it is found that under heavy load, the voltage gain is affected by junction capacitors of the primary side switching and the parasitic parameters of the secondary side diodes converted to the primary side, which will cause the voltage gain decreased when the switching frequency decreased.
Design/methodology/approach
This paper proposes an optimization parameters design method to solve this problem, which was based on impedance model considering the parasitic parameters of switching devices and diodes.
Findings
The effectiveness of the proposed method is verified by impedance Bode plots and experimental results.
Originality/value
From the perspective of impedance modeling, this paper finds the reasons for the insufficient voltage regulation capability of LLC resonant converters under heavy load and finds solutions through analysis.
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Sifeng Liu, Yong Tao, Naiming Xie, Liangyan Tao and Mingli Hu
The purpose of this paper is to summarize the advances in grey system theory research and various application achievements in science and engineering. At the same time, it…
Abstract
Purpose
The purpose of this paper is to summarize the advances in grey system theory research and various application achievements in science and engineering. At the same time, it commemorates the 40th anniversary of the birth of grey system theory and the 10th anniversary of Grey Systems–Theory and Application.
Design/methodology/approach
Firstly, the innovations of theoretical research in grey system theory were summarized and some of the widely recognized new results are briefly described. By searching and combing the research results of grey system theory in China national knowledge infrastructure (CNKI) database and Web of Science by Institute for Scientific Information (ISI), this paper shows the rapid development trend of grey system theory in the past 40 years, and the successful applications of grey system theory in the fields of social sciences, natural sciences and engineering technologies.
Findings
More than 227 thousands literature were found by input 10 phrases such as grey system, grey number and sequence operator etc. in CNKI database. After entering the new century, the number of grey system papers included in CNKI database is increasing rapidly. Since 2008, more than 10 thousands papers have been included per year and more than 15 thousands papers have been included per year since 2014. Grey system method and model are widely used in physics, chemistry, biology and other fields of natural science, as well as transportation, electric power, machinery and other fields of engineering technology, and a large number of valuable results have been achieved.
Practical implications
It can be seen that the grey system theory plays an important role in promoting China’s scientific and technological progress, innovation and development and high-level talent training from tens of thousands of literatures marked with important national science and technology projects and a large number of grey system literatures published by China’s double first-class universities and double first-class discipline construction universities.
Originality/value
Both innovations of theoretical research and practical application play important role in the growth of new theory. The innovations of theoretical research provide methods and tools for practical application, which is conducive to improve application efficiency and broaden application fields. A large number of practical applications needs have become the source of theoretical innovation and the solid background for the birth of theoretical innovation achievements.
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Murat Isik, Isa Emami Tabrizi, Raja Muhammad Awais Khan, Mehmet Yildiz, Eda Aydogan and Bahattin Koc
In recent years, additive manufacturing (AM) has started to be used for manufacturing real functional parts and assemblies for critical applications in aerospace, automotive, and…
Abstract
Purpose
In recent years, additive manufacturing (AM) has started to be used for manufacturing real functional parts and assemblies for critical applications in aerospace, automotive, and machinery industries. Most complex or assembled parts require internal features (IF) such as holes, channels, slots, or guides for locational and mating requirements. Therefore, it is critical to understand and compare the structural and mechanical properties of additively manufactured and conventionally machined IFs.
Design/methodology/approach
In this study, mechanical and microstructural properties of Inconel 718 (Inc718) alloy internal features, manufactured either as-built with AM or machining of additively manufactured (AMed) part thereafter were investigated.
Findings
The results showed that the average ultimate tensile strength (UTS) of additively manufactured center internal feature (AM-IF) is almost analogous to the machined internal feature (M-IF). However, the yield strength of M-IF is greater than that of AM-IF due the greater surface roughness of the internal feature in AM-IF, which is deemed to surpass the effect of microstructure on the mechanical performance. The results of digital image correlation (DIC) analysis suggest that AM-IF and M-IF conditions have similar strain values under the same stress levels but the specimens with as built IF have a more locally ductile region around their IF, which is confirmed by hardness test results. But this does not change global elongation behavior. The microstructural evolution starting from as-built (AB) and heat-treated (HT) samples to specimens with IF are examined. The microstructure of HT specimens has bimodal grain structure with d phase while the AB specimens display a very fine dendritic microstructure with the presence of carbides. Although they both have close values, machined specimens have a higher frequency of finer grains based on SEM images.
Originality/value
It was shown that the concurrent creation of the IF during AM can provide a final part with a preserved ultimate tensile strength and elongation but a decreased yield strength. The variation in UTS of AM-IF increases due to the surface roughness near the internal feature as compared to smooth internal surfaces in M-IF. Hence, the outcomes of this study are believed to be valuable for the industry in terms of determining the appropriate production strategy of parts with IF using AM and postprocessing processes.