Physical Co-location Research Articles

Ghost Riders: Sybil Attacks on Crowdsourced Mobile Mapping Services

Real-time crowdsourced maps, such as Waze provide timely updates on traffic, congestion, accidents, and points of interest. In this paper, we demonstrate how lack of strong location authentication allows creation of software-based Sybil devices that expose crowdsourced map systems to a variety of security and privacy attacks. Our experiments show that a single Sybil device with limited resources can cause havoc on Waze, reporting false congestion and accidents and automatically rerouting user traffic. More importantly, we describe techniques to generate Sybil devices at scale, creating armies of virtual vehicles capable of remotely tracking precise movements for large user populations while avoiding detection. To defend against Sybil devices, we propose a new approach based on co-location edges, authenticated records that attest to the one-time physical co-location of a pair of devices. Over time, co-location edges combine to form large proximity graphs that attest to physical interactions between devices, allowing scalable detection of virtual vehicles. We demonstrate the efficacy of this approach using large-scale simulations, and how they can be used to dramatically reduce the impact of the attacks. We have informed Waze/Google team of our research findings. Currently, we are in active collaboration with Waze team to improve the security and privacy of their system.

Physical distance vs. clustering as influences on contracting complexity for biopharmaceutical alliances

We examine whether the presence of alliance firms in the same regional cluster or in close physical proximity influences contracting behaviour of biopharmaceutical companies by enhancing coordination and mitigating the need for control. The literature addressing geographical proximity and alliance contracting fails to make a clear distinction between physical co-location and co-location within a cluster, although the two attributes are conceptually distinct. We find that geographic proximity is not related to contracting behaviour. The impact of co-location within a cluster is more nuanced. Specifically, we find that co-location in the San Francisco Bay Area cluster is associated with less complex contracting; however, co-location in other biotechnology clusters does not seem to be related to contracting behaviour. We believe that the informal business environment characterising the Bay Area cluster, as well as unique roles played by venture capital and law firms located in the Bay Area account for the distinct result.

Structuring Supplier Involvement in New Product Development: A China–U.S. Study

ABSTRACTBuying and supplying organizations rely on each other for developing better products in an efficient manner, which explains the popularity of involving suppliers in new product development (NPD). However, such involvement is not always successful, partially due to the challenges of structuring a buyer–supplier team to manage joint dependence and dependence asymmetry. This study adopts an organizational dependence view to examine how three types of intergroup structures—administrative (formalization and centralization), task (task interdependence), and physical (colocation)—influence project performance and buyer learning in NPD projects. Furthermore, adopting a contingency theory perspective, we study whether the national context moderates the effects of intergroup structures on project outcomes. We adopt a two‐group structural equation modeling approach to test hypotheses with survey responses from a sample of NPD projects in the United States (US) and China. Results show different ways in which intergroup structures influence project performance and buyer learning in the two culturally, economically, and institutionally distinct countries. We discuss the implications of these new findings and present directions for future research.

Place and culture-making: Geographic clumping in the emergence of artistic schools

In processes of cultural production, does it matter where the producers happen to be – and if so, how? We examine the formative years of 49 twentieth-century schools of painting, focused on the geographical locations of key participants. Our data suggest that in almost every instance, artists identified with a certain school tend to live in the same region or city during its emergent period, and often even in the same neighborhood of a large metropolitan area. This pattern continues throughout the 20th century, despite changes in communication and transportation that would seem to make physical co-location less vital for the formation of small collaborative circles in the arts. We speculate that emplacement is important not only for the emergence of new esthetic norms but also for the recognition of the group as a “school” and for its eventual success in the art market.

Control of the interface between heterotypic cell populations reveals the mechanism of intercellular transfer of signaling proteins.

Direct intercellular transfer of cellular components is a recently described general mechanism of cell–cell communication. It is a more non-specific mode of intercellular communication that is not actively controlled by the participating cells. Though membrane bound proteins and small non-protein cytosolic components have been shown to be transferred between cells, the possibility of transfer of cytosolic proteins has not been clearly established, and its mechanism remains unexplained. Using a cell–cell pair of metastatic melanoma and endothelial cells, known to interact at various stages during cancer progression, we show that cytosolic proteins can indeed be transferred between heterotypic cells. Using precise relative cell patterning we provide evidence that this transfer depends on extent of the interface between heterotypic cell populations. This result is further supported by a mathematical model capturing various experimental conditions. We further demonstrate that cytosolic protein transfer can have important functional consequences for the tumor–stroma interactions, e.g., in heterotypic transfer of constitutively activated BRAF, a common melanoma associated mutation, leading to an enhanced activation of the downstream MAPK pathway. Our results suggest that cytosolic protein transfer can have important consequences for regulation of processes involving physical co-location of heterotypic cell types, particularly in invasive cancer growth.

From Physical Co-location to Perceived Copresence: “I feel close to you when I use my mobile”

Mobile phones represent one of the most pervasive technologies of our time. This technology not only makes possible communication at a distance but also creates a communicative environment that enables the transportation of social life within the space-time system. Since young adults have largely embraced mobile technology for their everyday activities, this research analyses how individuals in the 18-24 years old age bracket realise their social life through mobile phones. The findings of this study conducted in New Zealand show that the use of mobile phones reshapes the young adults’ perceptions of their social space-time system. The evidence suggests that, regardless of whether the individuals are the call makers or the call takers when they talk to their loving partners, close family members and close friends, a subjective understanding of co-presence overshadows their physical co-location. Individuals perceive to be closer to their communication partners than to those in their corporeal proximity.

On information propagation in mobile call networks

We consider the dynamics of rapid propagation of information (RPI) in mobile phone networks. We propose a heuristic method for identification of sequences of calls that supposedly propagate the same information and apply it to large-scale real-world data. We show that some of the information propagation events identified by the proposed method can explain the physical co-location of subscribers. We further show that features of subscriber’s behavior in these events can be used for efficient churn prediction. To the best of our knowledge, our method for churn prediction is the first method that relies on dynamic, rather than static, social behavior. Finally, we introduce two generative models that address different aspects of RPI. One model describes the emergence of sequences of calls that lead to RPI. The other model describes the emergence of different topologies of paths in which the information propagates from one subscriber to another. We report high correspondence between certain features observed in the data and these models.

Outside the Cage: Exploring Everyday Interactions between Government Workers and Residents in a Place-Based Health Initiative

This paper presents an ethnographic case study of the daily lived experience of place by government health and community workers in a place-based chronic disease initiative (PBI) located in a disadvantaged peri-urban area in Australia. The case study focused on the place at which the PBI staff members interfaced with the community informally as opposed to the deliberate interactions described in the formal community engagement strategy. Subtle social phenomena, such as social positioning and the contrasting cultures of bureaucracy and community, generated outcomes that were the antithesis of those sought by the PBI. If these characteristics of place are not attended to during the development of PBIs, we risk recreating existing social divides and jeopardizing the potential of these initiatives to build community capacity. This case study provides an important conceptual-theoretical understanding of the place-based approach, which can augment existing empirical studies of place. The findings are also relevant for those who are exploring the physical co-location of diverse professional groups in socially disadvantaged neighbourhoods. It also exposes the inherent complexity of “place” and the futility of poorly designed bureaucratic responses.

Estimation and Identification of Merger Effects: An Application to Hospital Mergers

Abstract Existing empirical estimates of merger effects are compromised by the fact that merging and nonmerging entities differ in unobserved ways that independently affect outcomes of interest. To obtain an unbiased estimate of the effect of consummated mergers, I propose an approach that focuses on the response of rivals to mergers and accounts for the endogeneity of exposure to these mergers. I apply this approach to evaluate the impact of independent hospital mergers in the United States between 1989 and 1996. Using the physical colocation of rivals as an instrument for whether they merge, I find a sizeable, one‐time increase in price following a rival’s merger, with the greatest increase occurring among hospitals nearest the merging hospitals. These results are more consistent with predictions from structural models of the hospital industry than with prior observational estimates of the effects of hospital mergers.

Structural factors of NPD (new product development) team for manufacturability

We explore whether structural factors of NPD (new product development) team such as its physical co-location and team composition are still relevant and important in enhancing manufacturability as part of NPD performance in this highly virtualized coordination era as much as in the past before the Internet. We also examine how the analysis result is affected by the product’s innovativeness as well as other control variables like project duration and product type. In order to answer the research questions, we collected data on 127 projects of new product development at a global consumer electronics company. Based on our analysis, we conclude that whether the NPD members are physically co-located throughout the product development process and whether the team membership is balanced have profound implications for enhancing manufacturability.

A Multisite Study of Implementing Supported Employment in the Netherlands

A Multisite Study of Implementing Supported Employment in the Netherlands

Multidimensional modelling to investigate interspecies hydrogen transfer in anaerobic biofilms

Anaerobic digestion is a multistep process, mediated by a functionally and phylogenetically diverse microbial population. One of the crucial steps is oxidation of organic acids, with electron transfer via hydrogen or formate from acetogenic bacteria to methanogens. This syntrophic microbiological process is strongly restricted by a thermodynamic limitation on the allowable hydrogen or formate concentration. In order to study this process in more detail, we developed an individual-based biofilm model which enables to describe the processes at a microbial resolution. The biochemical model is the ADM1, implemented in a multidimensional domain. With this model, we evaluated three important issues for the syntrophic relationship: (i) Is there a fundamental difference in using hydrogen or formate as electron carrier? (ii) Does a thermodynamic-based inhibition function produced substantially different results from an empirical function? and; (iii) Does the physical co-location of acetogens and methanogens follow directly from a general model. Hydrogen or formate as electron carrier had no substantial impact on model results. Standard inhibition functions or thermodynamic inhibition function gave similar results at larger substrate field grid sizes (>10μm), but at smaller grid sizes, the thermodynamic-based function reduced the number of cells with long interspecies distances (>2.5μm). Therefore, a very fine grid resolution is needed to reflect differences between the thermodynamic function, and a more generic inhibition form. The co-location of syntrophic bacteria was well predicted without a need to assume a microbiological based mechanism (e.g., through chemotaxis) of biofilm formation.

Horizontal Mechanisms under Differing IS Organization Contexts

Horizontal mechanisms are structural overlays (such as roles and groups) and non-structural devices (such as physical co-location) that are designed to facilitate cross-unit collaboration. The objective of this study is to increase our cumulative knowledge about what top-down mechanisms are being used to promote the coordination of IS activities across corporate/division boundaries. Propositions about how mechanism usage differs under Centralized versus Federal IS organization contexts are developed based on a synthesis of prior organization science and empirical IS literature. Multiple methods are used to collect data from IS and non-IS senior managers from two case sites with theoretically different IS coordination needs. As predicted, multiple types of structural and non-structural mechanisms were implemented for business-IS coordination in the company with a Centralized IS context, and for corporate IS-decentralized IS coordination in the company with a Federal IS context. An unexpected finding was that mechanisms for both of these kinds of IS coordination were valued at each case site. The prediction that a formal group mechanism would be perceived as more effective for achieving cross-unit coordination than an integrator role mechanism was not supported. The article concludes with a discussion of implications for research and practice.

Physical Co-Location and the Success of New Product Development Projects

ABSTRACTThis study investigates the relationship between the use of physical co-location and the success of new product development projects. It is proposed that physical co-location leads to higher frequency of face-to-face meetings. The higher frequency of face-to-face meetings are proposed to lead to more successful new product development projects. Data were gathered from 82 firms. The findings indicate that physical co-location is positively related to the frequency of face-to-face meetings. The frequency of face-to-face meetings is significantly and positively correlated with a new product development project's schedule performance. There is also a borderline significance between the frequency of face-to-face meetings and a project's final product quality. The managerial implications of this study are presented.

The field service function in the electronics industry: Providing a link between customers and production/marketing

In today's economy, the importance of and emphasis on customer service has been steadily increasing. In response to this shift, the field of operations management has expanded both its teaching and research horizons to include not only the traditional concepts of production but also those of service operations. Companies are becoming increasingly aware of customer service as a competitive edge and, in many cases, as a competitive necessity. An important aspect of the service sector is the area of field service. Field service often represents a service organization within a manufacturing firm — providing customer service, a source of revenue, and a means for strategic competitive differentiation. Although field service has been recognized by many companies as a competitive edge, in-depth case studies of field service firms are difficult to find. In response to this lack of information, a research effort was undertaken focusing on field service leaders in the electronics industry. The electronics industry was chosen due to the emphasis on and the importance of field service to competitiveness; industry leaders such as General Electric Computer Services, Hewlett-Packard, IBM, NCR, were selected based on various industry rankings and on recommendations provided by field service consultants, practitioners, and personnel from national field service professional associations. Data were collected primarily through on-site interviews with field service and marketing managers from the various companies. On-site interviews, telephone interviews, facsimile transmissions, and mail correspondence were also utilized to gather data from other parties (recommended by the primary interviewees) and to correct any discrepancies. Areas studies include organization, strategy, performance measures, service processes, management information systems, and service parts management. Case summaries will be provided in addition to cross-case analysis. The research indicates that field service is a critical source of customer and product performance feedback. Additionally, in the six companies studied, field service management information systems and information flow are recognized as critical to not only the field service organization but also to the business as a whole. In addition to management information systems, the physical co-location of field service personnel within other company functions facilitates the cross-flow of information necessary to provide total customer account support.