Investigating online social media users’ behaviors for social commerce recommendations

Online social media create virtual communities and network platforms that people use to create, share, and exchange opinions, views and experiences. With social networks, social commerce not only relies on commerce, but online social media can also promote the sale of goods or services online. Many online operators have begun to use recommendation systems to analyze customer purchase history and identify individual products that customers may purchase. This enables the company to send product information to consumers to attract their attention. In addition, consumers have a higher purchase rate for recommended products based on consumer data. Based on a survey in Taiwan society, this study uses the questionnaire survey method to collect data on a relational database. This study investigates Taiwan online social media users’ behaviors using data mining methods, including clustering analysis and association rules. Clustering analysis is to investigate possible profiles of users and association rules are to find knowledge patterns and rules of user profiles, online social media usage motivation/preferences and social commerce behavior in order to generate social commerce recommendations in terms of social technology development in the modern society.     

Investigating different types of research collaboration and citation impact: a case study of Harvard University’s publications

This study aims to investigate the influence of different patterns of collaboration on the citation impact of Harvard University’s publications. Those documents published by researchers affiliated with Harvard University in WoS from 2000–2009, constituted the population of the research which was counted for 124,937 records. Based on the results, only 12% of Harvard publications were single author publications. Different patterns of collaboration were investigated in different subject fields. In all 22 examined fields, the number of co-authored publications is much higher than single author publications. In fact, more than 60% of all publications in each field are multi-author publications. Also, the normalized citation per paper for co-authored publications is higher than that of single author publications in all fields. In addition, the largest number of publications in all 22 fields were also published through inter-institutional collaboration and were as a result of collaboration among domestic researchers and not international ones. In general, the results of the study showed that there was a significant positive correlation between the number of authors and the number of citations in Harvard publications. In addition, publications with more number of institutions have received more number of citations, whereas publications with more number of foreign collaborators were not much highly cited.     

Exploring the determinants of users’ continuance intention in smartwatches

The purpose of this study is to examine possible factors that influence continuance intention to use a smartwatch. The proposed research model is based on the expectation confirmation model adapted to include individual mobility, perceived aesthetics, and habit. The sample consisted of 348 actual users of smartwatches and structural equation modeling (SEM) was employed to test the research model. The results indicate that perceived aesthetics, satisfaction, individual mobility, and habit are associated with individuals’ continuance intention to use smartwatches. Surprisingly, perceived usefulness does not directly influence continuance intention of smartwatches. The implications for both theory and practice are provided based on the findings.     

Smart systems for determination of drug’s solubility

The solubility of drugs is a crucial physicochemical property in the drug discovery or development process and for improving the bioavailability of drugs. There are various methods for evaluating the solubility of drugs including manual measurement methods, mathematical methods, and smart methods. Manual measurement and mathematical methods have some defects which make the smart systems more reliable and important in this field. In this review, various instruments used for the solubility determination, along with the smart systems, have been discussed. Mechanism and applications of each method have been elaborated in detail. Moreover, unique characteristics as well as some limitations of discussed methods are also described.     

Comment on ‘Economic analysis of inventory systems’

This paper deals with the problem of designing a hierarchical production planning system, where higher level decisions impose constraints on lower level decisions. This paper supports the choice of a production planning system for a two-stage process. First, analytical models clarify the relationship between production planning rules and the role of buffer inventory level in terms of manufacturing performance. Second, from the results of the analysis, a numerical example is presented on a production planning system designed under various management policies.     

Suspicious minds? – users’ perceptions of autonomous and connected driving

Abstract

In this article, the public perception and acceptance of novel vehicle technologies – autonomous driving (AD) and connected driving (CD) – is investigated. Following a multistep empirical procedure, we explore participants’ cognitions towards AD and CD. Therefore, a questionnaire study was run in which the perceived benefits and barriers of the technologies were evaluated by 443 participants in a wide age range (18–76 years). In addition, we took a closer look at the impact of user diversity (gender, age, need for privacy, control, risk taking tolerance and technical self-efficacy) on the evaluation of both driving technologies. Finally, cluster analyses were used out to identify evaluation profiles in both benefits and barriers, respectively. Overall, CD is seen significantly more positive compared to AD. With increasing risk taking tolerance and technical self-efficacy, the perception of the benefits was higher. In contrast, the perception of barriers in novel vehicle technologies was independent of personality factors and attitudes. Here, privacy and data protection issues were seen as key disadvantages. The findings can be used to develop timely and individually tailored public information and communication strategies for automated and connected vehicle technologies.     

Investigating risks of outcome-based service contracts from a provider’s perspective

Outcome-based contracts (OBC) refer to agreements between providers and customers where providers are paid based on the outcomes they deliver to customers. OBCs have become common for manufacturing firms that are servitising, especially those firms providing advanced services focusing on availability and capability. Whilst many authors acknowledge the importance of understanding risks in OBCs from a provider’s perspective, there are relatively few in depth extant studies. To address this gap in the literature, we conducted 24 interviews with 11 companies to explore risks and risk factors in OBCs from the provider’s perspective. The case studies reveal that the two major risk categories in OBCs are commercial risk regarding the contract negotiations and contract decisions at the contracting stage, and operational risk regarding the implementation and the delivery of OBCs. Our study identifies 23 risk factors that can lead to commercial risk and operational risk in five dimensions: (i) complexity and (ii) dynamism regarding the context of OBCs, (iii) capability, (iv) alignment and (v) dependency regarding the stakeholders of OBCs. The paper explores the links between these risk factors and commercial and operational risk. In doing so, the paper provides a framework for understanding risk in OBCs.     

Derivatives of α-zirconium phosphate with two different functional groups

The syntheses of derivatives of α-zirconium phosphate having the general formula Zr(RPO₃)_x(R′PO₃)_2−x (where R and R′ are generally organic radicals, but may also indicate −H or −OH groups) have been achieved by precipitating a mixture of two phosphonic acids with a zirconium salt in the presence of hydrofluoric acid. Different mixed compounds, classified in the following three classes

• 1.(a) Zr (HPO₄)_x (R′PO₃)_2−x (R′ = −H; −C₆H₅; −CH₂CH ₂COOH)
• 2.(b) Zr (RPO₃)_x (R′PO₃)_2−x (R′ = −CH₂COOH;R′ = −CH₂OH)
• 3.(c) Zr (HPO₃)_x (R′PO₃)_2−x (R′ = −CH₆H₅; −CH₂OH; −CH₂COOH; −CH₂CH₂COOH)

were prepared and characterized with regard to their compositions, X-ray powder patterns and densities. It was found that the system is discontinuous, not all x values from 0 to 2 being possible. No single crystals for X-ray structure determination were obtained; however, some chemical evidence shows that the mixed compounds possess a layered structure similar to that of α-zirconium phosphate. Some considerations on the reciprocal disposition of the R and R′ pendent groups in the layered structure are reported. Many other derivatives are expected to be obtained easily by using other mixtures of phosphonic acids than those employed in this work. Owing to the large variety of possible combinations of R and R′ groups, the mixed compounds should exhibit a large spectrum of properties and show promise for application in the field of ion exchange, adsorption, intercalation and heterogeneous catalysis.     

Relative visibility of authors’ publications in different information services

This study is to examine the structure, characteristics, and change of a research collaboration network using co-assignee information of joint patents in Korea. The study was conducted in three stages: data collection, network construction, and network analysis. For network analysis, network topological analysis, node centrality analysis, and block modeling were performed in sequence. The analysis results revealed that the network has small-world properties. The results also showed that while government-sponsored research institutes (GRIs) played a role as a hub and bridge in the network in the early 2000s, universities gradually took their place to play a key role as a hub and bridge in the network. In addition, the block modeling analysis indicated that while, in the early 2000s, GRI-centered network density was shown to be high, the network density became concentrated around universities after 2004, and this tendency intensified after 2008. Bearing in mind a lack of empirical studies on inter-organizational research collaboration networks using patent data, this study made an academic contribution by specifically analyzing the structure and change of research collaboration networks by targeting Korea’s major innovative actors. From the policy perspective, it provides important implications for figuring out the effects of university–industry–GRI (UIG) collaboration policies implemented so far, and can be of assistance for making evidence-based policies to build up a more effective UIG collaboration network or establish a new national science and technology innovation system.     

Energy consumption of cold climate heat pumps in different climates – Comparison of single-stage and two-stage systems

The aim of the study presented in this paper is the comparison of different possibilities to reduce the power consumption and environmental impact of barrack buildings of the US army. For this purpose different building standards, different heating and cooling appliances and a cold storage concept are compared using annual building simulations. These simulations are carried out for central and northern locations in the US. The focus of this paper is the applicability of cold climate heat pumps in these climates. A coupled building and appliance model has been established to allow a fair comparison based on first energy usage and CO₂ emissions. Altogether seven different building configurations in six different locations have been investigated. Simulation results show the most significant energy savings (up to 90%) can be achieved by improving building insulation and heat recovery of the ventilation system. Second major improvement is the usage of two-stage heat pump systems, which drastically reduces the need for backup heating systems and lead to seasonal efficiencies (SCOPs) in the area of 3.0, or in other words an energy saving of 20–35%. Thermal storage and control concepts such as night setback in comparison show little effect. The simulation results also showed that primary energy demand or greenhouse gas emissions are better measures for the comparison of environmental impact than COP and SCOP.     

Synthesis and characterization of biocomposites with different hydroxyapatite–collagen ratios

Hydroxyapatite (HA)-type I collagen (Col) composite is a tissue-engineered bone graft which can act as a carrier or a template structure for cells or any other agents. In this paper, the effect of Col ratio on the scaffold structure and composition was analyzed. Scaffolds composed by HA/Col with different weight ratios (80:20; 50:50; 20:80, and 10:90) were produced by the precipitation method at pH 8–9, 37°C and 6 h of ripening. Using X-ray diffraction data, the Rietveld structure refinement showed that the size of HA crystals along the c-axis direction (002) decreases significantly in the presence of Col. Thus, the HA crystal shape turned from needle-like in pure HA, into spherical, in the 10:90 composite due to Col fibrillogenesis. The homogeneity of the composite was significantly dependent on the amount of Col in it. HA/Col 20/80 composite presented HA particles in a more homogenous way. Such a biocomposite was successfully produced in a rapid way and it is potentially useful for both small tissue repairs and engineering.     

Selective removal of 17β-estradiol with molecularly imprinted particle-embedded cryogel systems

The selective removal of 17β-estradiol (E2) was investigated by using molecularly E2 imprinted (MIP) particle embedded poly(hydroxyethyl methacrylate) (PHEMA) cryogel. PHEMA/MIP composite cryogel was characterized by FTIR, SEM, swelling studies, and surface area measurements. E2 adsorption studies were performed by using aqueous solutions which contain various amounts of E2. The specificity of PHEMA/MIP cryogel to recognition of E2 was performed by using cholesterol and stigmasterol. PHEMA/MIP cryogel exhibited a high binding capacity (5.32 mg/gpolymer) and high selectivity for E2 in the presence of competitive molecules, cholesterol (k(E2/cholesterol) = 7.6) and stigmasterol (k(E2/Stigmasterol) = 85.8). There is no significant decrease in adsorption capacity after several adsorption-desorption cycles.     

A comparative analysis of constitutive behaviors of Mg–Mn alloys with different heat-treatment parameters

Mg–1.8Mn (wt.%) alloy was solution-treated by three regimes to obtain different initial microstructures. Isothermal hot compression tests were conducted in the temperature range of 250–450 °C and strain rate 0.01–1 s⁻¹ for each of the initial states. Constitutive constants for each initial state were obtained and compared. The results showed that homogenization of initial microstructure can significantly decrease the deformation resistance during hot working. It was also revealed that the dispersion of second-phase particles 1–1.5 μm in size with appropriate volume fraction (1–2%) and inter-particle spacing in initial microstructure can impart superior hot work deformation ability to the materials. Excessive amounts of particles resulted in an increase of the flow stresses and working-hardening degree. A large volume fraction of nano-sized particles also imposed difficulty in plastic deformation but with less harmful effects than the larger-sized particles. The influencing mechanism of the particle distribution on the constitutive behavior is discussed.     

Micromechanical modelling of bituminous materials’ complex modulus at different length scales

The aim of this work is to establish a multi-scale modelling technique usable in the study of the complex viscoelastic properties of asphalt mixes. This technique is based on a biphasic approach. At each scale, the heterogeneous media is considered as a two-phase material composed of granular inclusions with linear elastic properties and a matrix of bituminous materials exhibiting linear viscoelastic behaviour at small strain values. In this approach, the homogeneous equivalent properties of biphasic composites are transferred from one scale of observation to the next, higher scale of observation. The viscoelastic properties of the matrix and the elastic properties of the aggregates serve as the input parameters for the numerical models. The generalised Maxwell rheological model is used to describe the viscoelastic behaviour of the matrix. Thanks to the rheological properties of bitumen and the elastic properties of the aggregates, the viscoelastic properties of mastic, mortar and hot mix asphalt (HMA) as bituminous composites can be, respectively, estimated using a micromechanical finite element model. Random inclusions of varying sizes and shapes are generated in order to construct the granular skeleton. A cyclic loading was imposed on the top layer of the digital model. The dynamic modulus of the pre-cited bituminous composites, obtained from the presented multi-scale modelling process while passing from the bitumen to the HMA scale, is validated by comparison with experimental measurements when possible. Concerning our results, we have found that at low temperature (?10 °C), the predicted dynamic modulus is satisfactorily comparable to the experimental measurements. On the other hand, an acceptable gap between predicted numerical results and experimental data takes place when the temperature increases.     

Decentralized robust control of multi‐machine power systems with a prescribed degree of stability

Abstract

This paper presents a completely decentralized scheme for the robust control of multi‐machine power systems with a prescribed degree of stability. By applying the optimal control technique to the nominal dynamics of each decomposed machine, the calculated optimal gains are multiplied by appropriate factors to account for the intrinsic uncertainties and nonlinear interactions among the machines. This subsystem‐based method can give the overall system an arbitrarily chosen degree of stability, where no state information is transferred. An example of a three‐machine power system is given below.