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

A Biosynthetic Membrane-Anchor/Protein System Based on a Genetically Encoded Aldehyde Tag

Lipid membranes or bilayers serve as barriers for the cell and its organelles. A distinguishing feature of cellular function is the ability to monitor and process the biochemical information between the cells’ intra and extracellular environments in order to maintain the homeostatic reactions that are essential to life. Surface membrane proteins play a key role in mediating this information exchange by functionalizing the bilayer. As a result of their importance in living systems, proteins are integrated into biomimetic membrane systems to replicate their natural functions in biomedical technologies. Current protein integration methods are limited by the selection of commercially available lipids for attachment onto the target protein and by the location along the protein in which successful coupling to a lipid anchor may occur. The recent developments of an “aldehyde tag” have shown that the insertion of a 6 amino acid consensus sequence into a protein is sufficient to target it for post-translational modification by formylglycine-generating enzyme (FGE). FGE will enzymatically transform the cysteine in the consensus sequence into a formylglycine, thus leading to the site-specific introduction of an aldehyde side chain for further chemical modification such as lipidation. We introduced the consensus sequence on the C-terminus of an enhanced green fluorescence protein (EGFP) and co-expressed it with FGE in E. Coli to maximize the yield of aldehyde conversion. Lipids were chemically modified to bear a reactive aminooxy group and then covalently attached to the aldehyde tagged EGFP in aqueous solution. The resulting EGFP-lipid constructs were successfully incorporated into a solid supported lipid bilayer as verified by fluorescence microscopy. Membrane integrity as well as protein and lipid mobility was analyzed using fluorescence recovery after photo-bleaching (FRAP). This site-specific lipidation strategy promises to allow for the use of a variety of different lipid anchors and to provide unprecedented freedom in the choice of the lipidation site on the target protein

VALUATION EFFECTS OF BUSINESS PROCESS OUTSOURCING: MAKING THE CASE FOR SELECTIVE GOVERNANCE

Business Process Outsourcing (BPO) has grown in incidence and importance over the past few years. However, beyond some expository studies, academic research on this phenomenon is sparse. Further, studies on IT outsourcing have primarily used a transaction cost economics (TCE) lens, and largely neglected other key theoretical explanations of the outsourcing decision and performance. In this dissertation, we examine how process level variables (process value chain position, relational governance, and process maturity) affect the excess stock return of a company. Drawing on the value chain framework, TCE, the resource based view, and institutional perspectives, we present a research model and propose a number of direct and moderating hypotheses. The three direct hypotheses suggest that BPOs of primary processes, BPOs with a higher level of relational governance, and abstention based BPOs induce stronger positive valuation impact than BPOs of supportive processes, BPOs with a lower level of relational governance, and disintegration based BPOs respectively. Based on TCE\u27s discriminant alignment hypothesis, the two moderating hypotheses suggest that primary BPOs and disintegration based BPOs are likely to bring stronger positive valuation enhancement when aligned with stronger relational governance capabilities. Using secondary data on 298 BPO announcements from 1998 to 2005, we test the proposed model with multivariate regression, group t tests, and nonparametric analyses. Overall, the results from statistical analyses validate our process based view of outsourcing as an alternative to the dominant functional view of outsourcing. In contrast to the significant positive excess returns received by primary BPOs, supportive BPOs suffer negative abnormal returns. The negative returns become even more pronounced for those supportive processes outsourced after internal deployment. Although we do not find the predicted performance superiority associated with abstention based BPOs, we confirm that a higher level of relational governance strongly enhances firm valuation. This positive valuation impact of relational governance reaches an even higher level in situations of primary BPOs and disintegration-based BPOs, which are posited to require a greater presence of relational governance. For researchers, this study provides a novel approach that demonstrates how TCE and other traditionally competing theories can be used in a complementary manner. We illustrate the importance of alignment between process characteristics and relational governance. In addition, we sensitize researchers to the importance of the temporal dimension of processes and the concept of abstention based outsourcing. Future research can add granularity to these concepts and build on the discriminating alignment hypotheses. Based on the empirical results, we present BPO guidelines that reflect the importance of considering all processes for outsourcing, the critical consideration of relational governance, and the importance of planning governance structures that are aligned with the maturity and nature of the process being outsourced. Keeping in mind the dynamic nature of business process, managers should also be prepared to periodically reassess the alignment between the governance mechanism and process requirements, and make structural adjustments if necessary