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This paper aims to present a machine learning framework for using big data analytics to predict the reliability of solder joints. The purpose of this study is to accurately predict the reliability of solder joints by using big data analytics.

A machine learning framework for using big data analytics is proposed to predict the reliability of solder joints accurately.

A machine learning framework for predicting the life of solder joints accurately has been developed in this study. To validate its accuracy and efficiency, it is applied to predict the long-term reliability of lead-free Sn96.5Ag3.0Cu0.5 (SAC305) for three commonly used surface finishes such OSP, ENIG and IAg. The obtained results show that the predicted failure based on the machine learning method is much more accurate than the Weibull method. In addition, solder ball/bump joint failure modes are identified based on various solder joint failures reported in the literature.

The ability to predict thermal fatigue life accurately is extremely valuable to the industry because it saves time and cost for product development and optimization.

Extrusion-based additive manufacturing (AM) has been considered as a promising technique to fabricate scaffolds for tissue engineering due to affordability, versatility and ability to print porous structures. The reliability and controllability of the printing process are necessary to produce 3D-printed scaffolds with desired properties and depend on the geometric characteristics such as porosity and pore diameter. The purpose of this study is to develop an analytical model and explore its effectiveness in the prediction of geometric characteristics of 3D-printed scaffolds.

An analytical model was developed to simulate the geometric characteristics of scaffolds produced by extrusion-based AM using fluid mechanics. Polycaprolactone (PCL) was chosen as a scaffold material and was assumed to be a non-Newtonian fluid for the model. The effectiveness of the model was verified through comparison with the experimental results.

A comparison study between simulation and experimental results shows that strut diameter, pore size and porosity of scaffolds can be predicted by using extrusion pressure, temperature, nozzle diameter, nozzle length and printing speed. Simulation results demonstrate that geometric characteristics have a strong relationship with processing parameters, and the model developed in this study can be used for predicting the scaffold properties for the extrusion-based 3D bioprinting process.

The present study provides a prediction model that can simulate the printing process by a simple input of processing parameters. The geometric characteristics can be predicted prior to the experimental verification, and such prediction will reduce the process time and effort when a new material or method is applied.

To provide a design guideline for an automotive electronic module in order to improve its reliability in elevated environmental environments as well as in vibration environments.

Wire looping profiles, gel heights, and effects of mechanical vibration on aluminium wire bond failures are studied. Natural frequencies of various wire profiles are evaluated and effects of gel heights on reliability of products are studied using stochastic finite element analyses. The frequency dependent properties of silicone gels used in electronic modules are characterized by the corn and plate test. An experiment was also conducted in order to confirm numerical results.

The present study shows that the gel plays an important role in wire bond failures and reliability of the product. The gel reduces the amplitude of vibration of electronic modules due to its damping characteristics. However, both analytic and experimental results indicate that the gel imposes extra weight on the wires and may induce stresses on heels.

In the future study, it is suggested that other gel materials should be studied since the properties of gel strongly depend on the frequency which will affect the fatigue behavior of bonding wires.

The findings can be used as general design guidelines for wire bonding for automotive electronic modules.

The results will be very useful to design bonding wires for automotive electronic modules.

The purpose of this paper is to present the design and manufacture of embedded passive devices in organic substrates.

Low cost and high performance duplexers have been designed for WiMAX front‐end modules with multi‐layered organic substrates. Band‐pass filters (BPFs) and duplexers for the WiMAX FEM have been embedded in organic substrates. In addition, a new organic substrate manufacturing process has been proposed in order to improve the tolerance of embedded passives in organic substrates.

The overall size of FEM, which includes PA and bypass capacitor, is 5.4×4×1.5 mm. BPFs and duplexer show good electrical performances with low insertion loss and high attenuation. The dual‐band FEM with embedded passive components incorporates the duplexers including 2 and 5 GHz BPFs. The dimensions of BPFs and duplexer are 1.65×1.8×0.12 mm, 1.32×1.2×0.12 mm and 2×2×0.6 mm, respectively. The integrated dual‐band BPFs show an insertion loss < 1.8 dB in path band and 22‐40 dB attenuation performance in rejection band. The newly proposed fabrication process improves the tolerance for embedded capacitors in the organic substrate. This new process provides two main advantages. First, the flat coating process is not required. Second, it has a better copper pattern tolerance since the pattern is achieved with the addictive process. The tolerance of capacitances produced by the newly proposed process is compared with one manufactured by the conventional etching process. The newly proposed process provides a better capacitance tolerance.

In future studies, it is suggested that the tolerance study should include other variations such as thickness, alignment and material properties.

The paper's findings can be used for designing and manufacturing embedded passives devices for wireless applications.

This study shows a technology development in the area of embedded passive devices in organic substrates.

The purpose of this paper is to provide a design and material selection guideline for a plastic ball grid array (PBGA) package in order to improve its reliability and manufacturing ability after post mold cure.

Numerical experiments based on a three‐dimensional (3‐D) viscoelastic finite element method have been conducted to evaluate governing damage mechanisms after post mold cure (PMC) for PBGA packages. The parametric studies for the PBGA package with various molding compounds have been performed. A wide range of the modulus (1MPa∼15GPa) and the coefficient of thermal expansion (CTE) (10ppm∼300ppm) are evaluated to see feasibility of a new class of material set in the molding compound. Effects of thermo‐mechanical properties of selected molding compound on the warpage and residual stress of the PBGA are analyzed.

The present study shows that the material properties such as modulus and CTE of molding compounds play an important role in warpages and reliability of PBGA packages. After post mold cure, compressive normal stress σ_xx is observed in the silicon die, while tensile stress occurs in the rest of the PBGA package. The maximum normal stress σ_xx is observed at the center of the silicon die and decreases near the edge of the package. As the coefficient of thermal expansion of the silicon die is substantially less than that of the molding compound or substrate, the molding compound and the substrate are trying to shrink more when temperature decreases and in turn compressing the silicon chip. The molding compound with low modulus produces low stresses in the Si die and the die attach. Moreover, for the low modulus case, the CTE of molding compound does not affect the warpage of the PBGA package and the stresses in the silicon die or the die attach. However, for the high modulus case, the warpage and stresses are increased significantly by increasing the CTE of molding compound.

It is suggested that adhesion strengths of die attaches should be studied in future studies, since those affect the delamination between dies and substrates.

The findings can be used as general design guidelines for a PBGA package.

The results presented in the paper will be very useful to designers of PBGAs.

Presents the results of a study of the effects of solder ball pad metallurgy, intermetallic compound (IMC) thickness and thermal cycling on the shear strengths of PBGA package solder balls. The study of the microstructures of solder balls revealed that only a very thin layer of intermetallic compound existed between solder balls and Ni or Ni alloy barrier layers immediately after ball placement and reflow. The protective Au layer was dissolved completely and a needle like AuSn₄ intermetallic compound was then formed and dispersed evenly in the solder balls. The overall thickness of the IMC layers was thicker than 15μm after storage at 150°C for 1,000 hours. During the shear tests failure occurred at the interface of the two IMC layers. The fracture surfaces of solder balls with electrolytic Ni and thick Au layers were smooth and brittle fracture was observed. The ball shear strength decreased dramatically with the formation of IMC layers. For the solder balls with electroless Ni and thin Au layers, only a single IMC layer was formed at the interface and its thickness was only 2.5 μm after storage at 150°C for 1,000 hours.

The purpose of this paper is to examine the issue of the influential factors of buyer satisfaction and loyalty toward online auction web sites and online auction sellers. Customers' loyalty toward the online auction web site and seller is also explored.

An internet survey is conducted on 221 buyers of online auction.

Loyalty intention toward an online auction seller positively affects a buyer's loyalty intention toward the online auction web site, whereas his/her loyalty intention toward the online auction web site negatively affects his/her loyalty intention toward the online auction seller.

The first is in its cross‐sectional design. Second, this paper examines the antecedents of the online auction web site and the online auction seller in a single country. The findings may have limited generalizability to other countries.

The results of this paper provide less positive news for online auction sellers. Sellers on an online auction web site should be careful in making online auction web site change decisions. Although a seller can secure buyer loyalty intention by providing strong e‐service quality, overall satisfaction and the specific asset investment (SAI), buyers still may not be enthusiastic about moving with the seller to another auction web site.

This paper contributes to comparing the pulling force of the web sites and the sellers, and explains that SAI can affect the buyers through web sites and sellers. There are three parties involved in the model.

Industrialization in capitalist societies ushered in the growth of trade unions and the development of union activities of industrial workers. In the late eighteenth and the early nineteenth centuries in the West when unionism began, trade unions took diverse forms. These forms varied by society and were significantly influenced by the country’s specific historical background and socioeconomic and cultural conditions. Yet such diverse union structures began to merge into “industrial unionism” in the late nineteenth century, which embraced all types of workers within the boundaries of an industry. Industrial unionism has been considered the organizational form that most effectively ensures the collective power of trade unions and their sociopolitical sway over contending forces, notably, the state and employers’ associations, and thus has remained a prototypical union system. Accordingly, nonwestern societies and latecomers to unionism in the West have modeled their unions on the basis of the industrial union structure.

This paper explores how gender-related issues are communicated in Korean family-run conglomerates (chaebols) and the roles of women within these businesses. It also addresses to what extent the communication of chaebols about female employment and career development reflects the perception of gender representation in these organisations.

By paying attention to gendered discourse in Korean chaebols, this paper examines what is said and written about gender issues in glottographic statements (texts) and non-glottographic statements (charts and other visuals) of annual reports (ARs) published by five chaebols since 2010. The paper uses a Foucauldian framework to develop the archive of statements made within these ARs.

Although there is an increase in female-employee ratios, ARs show that number of women at the board or senior management level continue to be small. ARs tend to provide numbers related to female employment and retention in their non-glottographic statements, yet these numbers occasionally differ from and frequently are not explained by glottographic statements. The strategies used by chaebols to improve career prospects for their female staff are only vaguely described and rarely evaluated.

This paper looks beyond the existing discourse analysis on “talk and text” by also investigating claims made through graphic and linear/pictorial elements and their interplay with text. This approach opens new understandings of how gendered discourses are constructed and how they (unintentionally) fail to resolve issues and perceptions related to female employment and career development in Korea.