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The purpose of this paper is to evaluate the influence of assembly parameters on lead-free solder joints reliability in Package-on-Package (PoP) Technology and demonstrate factors important for this issue.

Two types of soldering materials and three different assembly procedures were used for assembly of PoP system. The reliability properties of assembled PoP systems were investigated using accelerated aging and periodic resistance measurements of daisy-chain solder joints systems. The purpose of such approach was to determine which soldering material (flux or solder paste) as well as which assembly process parameter (dipping depth of upper component in soldering material), would provide better reliability properties of the solder joints in the PoP system.

It was stated that both selected flux and solder paste dedicated to assembly of PoP systems can be utilized in soldering of PoP applications. More reliable PoP systems applications require larger attention regarding materials selection and assembly parameters. It is recommended 50 per cent dipping depth of ball’s height into soldering material during upper PoP component assembly for more reliable applications. For less demanding PoP systems, the process window from 30 up to 70 per cent is acceptable. All observed failures after thermal shocks occurred in upper PoP components.

This paper explains how materials and assembly parameters have influence on lead-free solder joints reliability in PoP systems. Especially, influence of process window for dipping procedure of upper components balls into soldering material was presented.

This paper presents a pop-up technique based on origamic architecture as a technological design solution for post-disaster temporary shelter systems. First of all, the concepts of disaster and post-disaster are briefly introduced, and the roles and needs of post-disaster temporary shelter systems, particularly in emergency periods, are reviewed. Second, pop-up techniques based on origamic architecture are briefly discussed. Third, a formal language for opening the cards of origamic architecture is introduced, out of which a geometric elasticity has been developed. With the language, a variety of flexible and expandable designs for shelter structures can be generated by incorporating different pop-up techniques. Finally, a prototype shelter has been constructed to demonstrate the adaptability and sustainability of the shelter within the local environment and the affected society, considering portability, low-cost, and easy in assembling by any unskilled person.

The purpose of this paper is to identify enablers and inhibitors to the adoption of mobile internet services by socioeconomically disadvantaged people: an understudied population adversely affected by digital inequality.

A qualitative study combining a questionnaire and semi-structured interviews. In total, 32 socioeconomically disadvantaged people explored mobile lottery services and subsequently were asked a series of semi-structured questions about their perceptions of the technology.

Users’ attitudes toward mobile internet services were ambivalent. They experienced some advantages of smartphones (including escaping spatiotemporal constrains, fashionableness, privacy, and cost-effectiveness) and conceived of mobile internet services in terms of social advantages (including their ubiquitous nature, fitting in socially and fear of being “left behind”). However, they also experienced barriers and concerns, such as limited mobile data packages, external barriers from mobile services (including security concerns, complex online help tutorials, irrelevant pop-ups, and a lack of personalized services) and internal psychological barriers (including technophobia, self-concept, and habitus).

The findings are of limited generalizability due to the small size of the sample. However, the study has implications for understanding the acceptance of technology among socioeconomically disadvantaged people.

The study has social implications for bridging digital inequality in terms of socioeconomic status.

While previous studies have primarily focused on enablers of adopting mobile internet services by active users, this study reveals both the promise of and the barriers to the use of such services by inactive users who comprise an under-served population.

This paper aims to discuss how collaborative classification works in online music information retrieval systems and its impacts on the construction, fixation and orientation of the social uses of popular music on the internet.

Using a comparative method, the paper examines the logic behind music classification in Recommender Systems by studying the case of Last.fm, one of the most popular web sites of this type on the web. Data collected about users' ritual classifications are compared with the classification used by the music industry, represented by the AllMusic web site.

The paper identifies the differences between the criteria used for the collaborative classification of popular music, which is defined by users, and the traditional standards of commercial classification, used by the cultural industries, and discusses why commercial and non‐commercial classification methods vary.

Collaborative ritual classification reveals a shift in the demand for cultural information that may affect the way in which this demand is organized, as well as the classification criteria for works on the digital music market.

Collective creation of a music classification in recommender systems represents a new model of cultural mediation that might change the way of building new uses, tastes and patterns of musical consumption in online environments.

The paper highlights the way in which the classification process might influence the behavior of the users of music information retrieval systems, and vice versa.

The purpose of this study is to promote a better understanding of performance assessment (PA) as a managerial means via analyses and discussion of the system and practice in an academic library.

One existing PA system of a university library is presented. Descriptive analyses of two specific system‐inherent problems, respectively: weighting scheme of the evaluated criteria and disqualification of the immediate supervisor as rater, are conducted. The purpose of PA is addressed with reference to PA and pay linkage. Circular supervision as an effective element to ultimately eliminate individual errors in an administration is discussed.

The PA system and practice of CL are flawed. First, the weighting scheme of the evaluated categories is so allocated that the least measurable category has the overriding power. Second, the most qualified evaluator (the direct supervisor) is deprived of the numeric rating vote. Third, the end ratings from the PA lead to unfair merit compensation decisions and salary inequity. Finally, the system lacks a circular supervision mechanism to eliminate undefeatable power in the administration.

With concrete examples and data, this study brings to light some serious problems that exist in a PA system. Via in‐depth analyses and discussion of specific issues, it touches upon circular supervision, a core element in a sound administration that needs to be adequately addressed.

The purpose of this paper is to investigate the related issues of physical annotation systems and also to study their historical development. Moreover, the paper provides a taxonomy of physical annotation systems, including augmented reality systems and concludes with future challenges concerning such systems.

The authors first provide a review and a comparison of existing physical annotation systems. The authors' classification of the physical annotation systems is based on the capabilities they provide.

Physical annotation systems evolve as technology progresses. However, there are issues such as cognitive overload, trust, transient associations, and integrating of social networking with physical annotations.

As technology develops, physical annotations will become increasingly important in daily life. Hence, there are important research issues to address with regards to physical annotation systems.

New better physical annotation systems are needed, which will change the way we do things in life, including personal memory, tourism, commerce, security, games, traffic management, entertainment and health.

Physical annotation systems will affect the relationships between people, between people and places and between people and things. There is a potential shift in the way people view the physical world, not only as what we see but as what we see through the devices we carry.

The paper is an original review of physical annotation systems; there does not seem to be many such reviews on this area. The paper presents a set of future challenges regarding such systems.

The three objectives served by this review are to provide readers a limpid insight about the topic performance management (PM), to analyse the latest trends in PM literature and to illustrate the theoretical perspectives. It would be fascinating for the practitioners and researchers to see the latest trends in the PM system, which is not yet covered in previous reviews. The study covers the historical and theoretical perspectives of human resource management practices. We also try to unveil some of the theoretical debates and conflicts regarding the topic.

We reviewed 139 studies on PM published within the last 20 years (2000–2020). The method used here is the integrative review method. The criteria used to determine studies are articles from peer-reviewed journals regarding the PM system published between 2000 and 2020. The initial search for studies was conducted using an extensive journal database, and then an intensive reference-based search was also done. Each selected article was coded, themes were identified, and trends for every 5 years were determined. All the articles were analysed and classified based on the methodology used to identify qualitative and quantitative studies.

The review concludes that PM literature's emphasis shifted from traditional historical evaluations conducted once or twice a year to forward-looking, feedback-enriched PM systems. By segregating the studies into 5-year periods, we could extract five significant trends that prevailed in the PM literature from 2000 to 2020: reactions to PM system, factors that influence PM system, quality of rating sources, evaluating the PM system and types of the PM system. The review ends with a discussion of practical implications and avenues for future research.

It is equally a limitation and strength of this paper that we conducted a review of 139 articles to cover the whole works in PM literature during the last 20 years. The study could not concentrate on any specific PM theme, such as exploring employee outcomes or organizational outcomes. Likewise, the studies on public sector and non-profit organizations are excluded from this review, which constitutes a significant share of PM literature. Another significant limitation is that the selected articles are classified only based on their methodology; further classification based on different themes and contexts can also be done.

The study is an original review of the PM literature to identify the latest trends in the field.

The purpose of this paper is to present challenges met during package-on-package (PoP) technology implementation in real surface-mount technology assembly processes.

The properties and behavior of different combinations of soldering materials, PoP components and soldering profiles were investigated, both in the laboratory and during production trials. The purpose of such an approach was identification of existing problems and challenges in lead-free PoP systems assembly as well as checking which soldering material designed to PoP is more suitable for this technology.

Technological trials are needed to select adequate soldering materials for PoP systems assembly, as laboratory tests of materials alone were not sufficient. The challenges of PoP technology were associated with the equipment utilized, the soldering materials, operational parameters and the soldering profile used for assembly. The localization of defects in PoP systems is very difficult and, in many cases, destructive methods have to be used on solder joints for the assessment and confirmation of failures.

This paper shows main materials and soldering challenges in lead-free PoP technology. In particular, the problem related with selection of soldering materials and soldering profiles for PoP was presented. Moreover, the issues that have to be taken into consideration during the planning of a PoP system assembly procedure are presented.

The purpose of this paper is to evaluate the influence of solder powders sizes applied in soldering materials used for Package-on-Package (PoP) system manufacture as well as other factors on reliability and mechanical strength of created solder joints in three-dimensional (3D) PoP structures.

The design of experiments based on the Genichi Taguchi method were used in the investigation. The main factors covered different printed circuit board (PCB) coatings, soldering materials with solder powders sizes from Types 3 to 7 and soldering profiles. The reliability of 3D PoP structures was determined by measurements of resistance of daisy-chain solder joints systems during thermal shocks (TS) cycles. The mechanical strength of solder joints in 3D PoP structures was determined by measurements of a shear force of “Top” layer of 3D structures at T0 and after 1,500 TS. The ANOVA was used for results assessment.

The size of solder powders applied in soldering materials had small (10 per cent) influence on mechanical strength of solder joints in 3D PoP structures. Small size of solder powder had positive effect on solder joints reliability in 3D PoP structures. Especially important was the selection of solder paste for “Bottom” layer of 3D PoP system (influence 17 per cent). Incorrect soldering profile (influence 46 per cent) or wrong selected PCB coating (influence 35 per cent) can very easily reduce the positive impact of soldering materials on solder joints reliability. It was stated that as low as possible soldering profile and organic solderability preservative (OSP) coating in the case of single-sided PCB are the best for 3D PoP structures due to their reliability.

This paper explains how different sizes of solder powders used nowadays in solder pastes influence on reliability and mechanical strength of the solder joints in 3D PoP structures. The contribution, in numerical values, of soldering materials, soldering profile and PCB coating on 3D PoP structures solder joints reliability as well as recommendations improving reliability of 3D PoP structures solder joints were presented.