997 research outputs found
Deep Room Recognition Using Inaudible Echos
Recent years have seen the increasing need of location awareness by mobile
applications. This paper presents a room-level indoor localization approach
based on the measured room's echos in response to a two-millisecond single-tone
inaudible chirp emitted by a smartphone's loudspeaker. Different from other
acoustics-based room recognition systems that record full-spectrum audio for up
to ten seconds, our approach records audio in a narrow inaudible band for 0.1
seconds only to preserve the user's privacy. However, the short-time and
narrowband audio signal carries limited information about the room's
characteristics, presenting challenges to accurate room recognition. This paper
applies deep learning to effectively capture the subtle fingerprints in the
rooms' acoustic responses. Our extensive experiments show that a two-layer
convolutional neural network fed with the spectrogram of the inaudible echos
achieve the best performance, compared with alternative designs using other raw
data formats and deep models. Based on this result, we design a RoomRecognize
cloud service and its mobile client library that enable the mobile application
developers to readily implement the room recognition functionality without
resorting to any existing infrastructures and add-on hardware.
Extensive evaluation shows that RoomRecognize achieves 99.7%, 97.7%, 99%, and
89% accuracy in differentiating 22 and 50 residential/office rooms, 19 spots in
a quiet museum, and 15 spots in a crowded museum, respectively. Compared with
the state-of-the-art approaches based on support vector machine, RoomRecognize
significantly improves the Pareto frontier of recognition accuracy versus
robustness against interfering sounds (e.g., ambient music).Comment: 29 page
Environment, Marketing Strategy, Performance, and International Exit: Why and How They Are Connected ——A Study on International Exit in the Chinese Outward Foreign Direct Investment (OFDI) Context
Although research on foreign market entry and expansion behaviour has attracted significant interest in the literature, there is a general lack of research (both conceptual and empirical) on the exit behaviour of Foreign Direct Investment (FDI) firms. To address this issue, the current study develops a conceptual framework by extending the Environment-Strategy-Performance (ESP) paradigm to include the exit decision as a consequence of current performance. This thesis draws notions from various theories including the ESP paradigm, fit theory, dynamic capabilities (DC) theory, and the theory of competitive advantage. The objective is to take an initial step towards reducing the discrepancy between previous conceptual research and empirical research on exit, by developing a conceptual framework and empirically examining it in the context of Chinese Outward Foreign Direct Investment (OFDI). It also aims to lay the conceptual foundation for subsequent empirical research on international marketing and international exit. Several research hypotheses are advanced and tested using questionnaire survey data. The main research results show that both dissatisfactory performance of a foreign affiliate, and the internal strategic misfit between a foreign affiliate and its headquarters are important triggers of the exit decision. However, when the moderating role of a foreign affiliate’s marketing capabilities is considered, the impact of strategic misfit on the exit decision becomes not significant, whereas the influence of dissatisfactory performance on the exit decision remains significant. The research results have generated new insights into both international marketing strategy and international exit behaviour. Implications for both headquarters’ managers and foreign affiliates’ managers are also discussed
Online-offline activities and game-playing behaviors of avatars in a massive multiplayer online role-playing game
Massive multiplayer online role-playing games (MMORPGs) are very popular in
China, which provides a potential platform for scientific research. We study
the online-offline activities of avatars in an MMORPG to understand their
game-playing behavior. The statistical analysis unveils that the active avatars
can be classified into three types. The avatars of the first type are owned by
game cheaters who go online and offline in preset time intervals with the
online duration distributions dominated by pulses. The second type of avatars
is characterized by a Weibull distribution in the online durations, which is
confirmed by statistical tests. The distributions of online durations of the
remaining individual avatars differ from the above two types and cannot be
described by a simple form. These findings have potential applications in the
game industry.Comment: 6 EPL pages including 10 eps figure
Privacy protection for RFID-based tracking systems
Abstract—RFID technology is increasingly being deployed in ubiquitous computing environments for object tracking and localization. Existing tracking architecture usually assumes the use of a trusted server which is invulnerable to compromise by internal and external adversaries. However, maintaining such a trusted server is unlikely in the real world. In this paper, we consider the problem of adding privacy protection to object tracking systems built upon passive RFID tags, without relying on a trusted server assumption. Our protocol continues to protect user privacy in the event of partial compromise of a server. I
Division of labor, skill complementarity, and heterophily in socioeconomic networks
Constituents of complex systems interact with each other and self-organize to
form complex networks. Empirical results show that the link formation process
of many real networks follows either the global principle of popularity or the
local principle of similarity or a tradeoff between the two. In particular, it
has been shown that in social networks individuals exhibit significant
homophily when choosing their collaborators. We demonstrate, however, that in
populations in which there is a division of labor, skill complementarity is an
important factor in the formation of socioeconomic networks and an individual's
choice of collaborators is strongly affected by heterophily. We analyze 124
evolving virtual worlds of a popular "massively multiplayer online role-playing
game" (MMORPG) in which people belong to three different professions and are
allowed to work and interact with each other in a somewhat realistic manner. We
find evidence of heterophily in the formation of collaboration networks, where
people prefer to forge social ties with people who have professions different
from their own. We then construct an economic model to quantify the heterophily
by assuming that individuals in socioeconomic systems choose collaborators that
are of maximum utility. The results of model calibration confirm the presence
of heterophily. Both empirical analysis and model calibration show that the
heterophilous feature is persistent along the evolution of virtual worlds. We
also find that the degree of complementarity in virtual societies is positively
correlated with their economic output. Our work sheds new light on the
scientific research utility of virtual worlds for studying human behaviors in
complex socioeconomic systems.Comment: 14 Latex pages + 3 figure
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