Stevens Institute of Technology

About: Stevens Institute of Technology is a education organization based out in Hoboken, New Jersey, United States. It is known for research contribution in the topics: Computer science & Cognitive radio. The organization has 5440 authors who have published 12684 publications receiving 296875 citations. The organization is also known as: Stevens & Stevens Tech.

Damage Detection in Thin Plates and Aerospace Structures with the Electro-Mechanical Impedance Method:

Abstract: The use of the electro-mechanical (E/M) impedance method for health monitoring of thin plates and aerospace structures is described. As a nondestructive evaluation technology, the E/M impedance method allows us to identify the local dynamics of the structure directly through the E/M impedance signatures of piezoelectric wafer active sensors (PWAS) permanently mounted to the structure. An analytical model for 2-D thin-wall structures, which predicts the E/M impedance response at PWAS terminals, was developed and validated. The model accounts for axial and flexural vibrations of the structure and considers both the structural dynamics and the sensor dynamics. Calibration experiments performed on circular thin plates with centrally attached PWAS showed that the presence of damage modifies the high-frequency E/M impedance spectrum causing frequency shifts, peak splitting, and appearance of new harmonics. Overall-statistics damage metrics and probabilistic neural network (PNN) are used to classify the spectral data and identify damage severity. On thin-wall aircraft panels, the presence of damage influences the sensors E/M impedance spectrum. When crack damage is in the PWAS medium field, changes in the distribution of harmonics take place and when crack damage is in the PWAS near field, changes in both the harmonics and the dereverberated response are observed. These effects are successfully classified with PNN and overall-statistics metrics, respectively. This proves that permanently attached PWAS in conjunction with the E/M impedance method can be successfully used in structural health monitoring to detect the presence of incipient damage through the examination and classification of the high-frequency E/M impedance spectra.

Drawdown Measure in Portfolio Optimization

Abstract: A new one-parameter family of risk measures called Conditional Drawdown (CDD) has been proposed. These measures of risk are functionals of the portfolio drawdown (underwater) curve considered in active portfolio management. For some value of the tolerance parameter Alpha, in the case of a single sample path, drawdown functional is defined as the mean of the worst (1 - Alpha) 100% drawdowns. The CDD measure generalizes the notion of the drawdown functional to a multi-scenario case and can be considered as a generalization of deviation measure to a dynamic case. The CDD measure includes the Maximal Drawdown and Average Drawdown as its limiting cases. Mathematical properties of the CDD measure have been studied and efficient optimization techniques for CDD computation and solving asset-allocation problems with a CDD measure have been developed. The CDD family of risk functionals is similar to Conditional Value-at-Risk (CVaR), which is also called Mean Shortfall, Mean Excess Loss, or Tail Value-at-Risk. Some recommendations on how to select the optimal risk functionals for getting practically stable portfolios have been provided. A real-life asset-allocation problem has been solved using the proposed measures. For this particular example, the optimal portfolios for cases of Maximal Drawdown, Average Drawdown, and several intermediate cases between these two have been found.

A single-cell landscape of high-grade serous ovarian cancer.

Abstract: Malignant abdominal fluid (ascites) frequently develops in women with advanced high-grade serous ovarian cancer (HGSOC) and is associated with drug resistance and a poor prognosis1 To comprehensively characterize the HGSOC ascites ecosystem, we used single-cell RNA sequencing to profile ~11,000 cells from 22 ascites specimens from 11 patients with HGSOC We found significant inter-patient variability in the composition and functional programs of ascites cells, including immunomodulatory fibroblast sub-populations and dichotomous macrophage populations We found that the previously described immunoreactive and mesenchymal subtypes of HGSOC, which have prognostic implications, reflect the abundance of immune infiltrates and fibroblasts rather than distinct subsets of malignant cells2 Malignant cell variability was partly explained by heterogeneous copy number alteration patterns or expression of a stemness program Malignant cells shared expression of inflammatory programs that were largely recapitulated in single-cell RNA sequencing of ~35,000 cells from additionally collected samples, including three ascites, two primary HGSOC tumors and three patient ascites-derived xenograft models Inhibition of the JAK/STAT pathway, which was expressed in both malignant cells and cancer-associated fibroblasts, had potent anti-tumor activity in primary short-term cultures and patient-derived xenograft models Our work contributes to resolving the HSGOC landscape3-5 and provides a resource for the development of novel therapeutic approaches

CIO Reporting Structure, Strategic Positioning, and Firm Performance

Abstract: Almost 30 years after the introduction of the CIO position, the ideal CIO reporting structure (whether the CIO should report to the CEO or the CFO) is yet to be identified. There is an intuitive assumption among some proponents of IT that the CIO should always report to the CEO to promote the importance of IT and the CIO’s clout in the firm, while some adversaries of IT call for a CIO-CFO reporting structure to keep a tab on IT spending. However, we challenge these two ad hoc prescriptions by arguing that neither CIO reporting structure is necessarily optimal, and that the CIO reporting structure should not be used to gauge the strategic role of IT in the firm.First, extending the strategy-structure paradigm, we propose that a firm’s strategic positioning (differentiation or cost leadership) should be a primary determinant of its CIO reporting structure. We hypothesize that differentiators are more likely to have their CIO report to the CEO in order to pursue IT initiatives that help the firm’s differentiation strategy. We also hypothesize that cost leaders are more likely to have their CIO report to the CFO to lead IT initiatives to facilitate the firm’s cost leadership strategy. Second, extending the alignment-fit view, we propose that firms that align their CIO reporting structure with their strategic positioning (specifically, differentiation with a CIO-CEO reporting structure and cost leadership with a CIO-CFO reporting structure) will have superior future performance.Longitudinal data from two periods (1990-1993 and 2006) support the proposed hypotheses, validating the relationship between a firm’s strategic positioning and its CIO reporting structure, and also the positive impact of their alignment on firm performance. These results challenge the ad hoc prescriptions about the CIO reporting structure, demonstrating that a CIO-CEO reporting structure is only superior for differentiators and a CIO-CFO reporting structure is superior only for cost leaders. The CIO reporting structure must, therefore, be designed to align with the firm’s strategic positioning, independent of whether IT plays a key strategic role in the firm.