| 1. |
- Beal, Jacob, et al.
(författare)
-
Robust estimation of bacterial cell count from optical density
- 2020
-
Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
-
Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
|
|
| 2. |
- Fallgren, Mikael, et al.
(författare)
-
Multicast and Broadcast Enablers for High-Performing Cellular V2X Systems
- 2019
-
Ingår i: IEEE Transactions on Broadcasting. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9316 .- 1557-9611. ; 65:2, s. 454-463
-
Tidskriftsartikel (refereegranskat)abstract
- This paper focuses on capabilities enabled by 5G connectivity in the cooperative, connected and autonomous cars, and elaborates on two technical enablers. One of the technical enablers consists of a beamformed broadcast/multicast technology that builds on adaptive and robust beam management techniques at the air interface. The other proposed technical component aims to improve the end-to-end architectural design of 5G networks to enable efficient broadcast and multicast transmissions for vehicle-to-anything services. Finally, the key results of multicast and broadcast technical components are described and ongoing and future areas of work and research are detailed.
|
|
| 3. |
- Song, Wenqing, et al.
(författare)
-
Heterogeneous Reconfigurable Accelerator for Homomorphic Evaluation on Encrypted Data
- 2024
-
Ingår i: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 12, s. 11850-11864
-
Tidskriftsartikel (refereegranskat)abstract
- Homomorphic encryption (HE) enables third -party servers to perform computations on encrypted user data while preserving privacy. Although conceptually attractive, the speed of software implementations of HE is almost impractical. To address this challenge, various domain -specific architectures have been proposed to accelerate homomorphic evaluation, but efficiency remains a bottleneck. In this paper, we propose a homomorphic evaluation accelerator with heterogeneous reconfigurable modular computing units (RCUs) for the Brakerski/Fan-Vercauteren (BFV) scheme. RCUs leverage operator abstraction to efficiently perform basic sub -operations of homomorphic evaluation such as residue number system (RNS) conversion, number theoretic transform (NTT), and other modular computations. By combining these sub -operations, complex homomorphic evaluation operations like multiplication, rotation, and addition are efficiently executed. To address the high demand for data access and improve memory efficiency, we design a coordinate -based address encoding strategy that enables in -place and conflict -free data access. Furthermore, specific optimizations are performed on the core sub -operations such as NTT and automorphism. The proposed architecture is implemented on Xilinx Virtex-7 and UltraScale+ FPGA platforms and evaluated for polynomials of length 4096. Compared to state-of-the-art accelerators with the same parameter set, our accelerator achieves the following advantages: 1) 2.04x to 3.33x reduction in the area -time product (ATP) for the key sub -operation NTT, 2) 1.08x to 7.42x reduction in latency for homomorphic multiplication with higher area efficiency, and 3) support for a wider range of homomorphic evaluation operations, including rotation, compared to other BFV-based accelerators.
|
|
| 4. |
|
|
| 5. |
- Zhao, Qian, et al.
(författare)
-
A flexible ammonia sensor based on MXene membrane with high sensitivity
- 2024
-
Ingår i: Electroanalysis. - : WILEY-V C H VERLAG GMBH. - 1040-0397 .- 1521-4109.
-
Tidskriftsartikel (refereegranskat)abstract
- Ammonia (NH3) of high concentration will pose a threat to ecological environment or human health, and exhaled NH3 is significant in disease monitoring and diagnosis. Thus, developing a highly sensitive gas sensor is significant to monitor NH3 concentration in complex environments. However, traditional NH3 sensors either need high working temperature, or face the challenge of poor conductivity/ sensitivity. In this work, NH3 sensors based on self-assembled MXene membrane have been fabricated. As-prepared sensors show a high sensitivity of 2.10 ppm-1 towards extremely low concentrations of NH3 (ppb level) at room temperature, attributed to large surface area and high conductivity. In addition, the sensors also display low detection limit (50 ppb), fast response time (41 s), good recoverability, long-term stability (15 days) and excellent flexibility (1000 bending cycles) towards NH3. The results provide insights into the development of highly sensitive NH3 sensors for industrial or biomedical applications. image
|
|
| 6. |
- Li, Zishuo, et al.
(författare)
-
Secure State Estimation against Sparse Attacks on a Time-varying Set of Sensors
- 2023
-
Ingår i: IFAC-PapersOnLine. - : Elsevier BV. ; , s. 270-275
-
Konferensbidrag (refereegranskat)abstract
- This paper studies the problem of secure state estimation of a linear time-invariant (LTI) system with bounded noise in the presence of sparse attacks on an unknown, time-varying set of sensors. At each time, the attacker has the freedom to choose an arbitrary set of no more than p sensors and manipulate their measurements without restraint. To this end, we propose a secure state estimation scheme and guarantee a bounded estimation error irrespective of the attack signals subject to 2p-sparse observability and a mild, technical assumption that the system matrix has no degenerate eigenvalues. The proposed scheme comprises a design of decentralized observers for each sensor based on the local observable subspace decomposition. At each time step, the local estimates of sensors are fused by a median operator to obtain a secure estimation, which is then followed by a local detection-and-resetting process of the decentralized observers. The estimation error is shown to be upper-bounded by a constant which is determined only by the system parameters and noise magnitudes. Moreover, we design the detector threshold to ensure that the benign sensors never trigger the detector. The efficacy of the proposed algorithm is demonstrated by its application on a benchmark example of IEEE 14-bus system. We show that our proposed scheme can effectively tolerate sparse attacks on an unknown set of sensors, ensuring a bounded estimation error and effectively detecting and resetting the attacked sensors.
|
|
| 7. |
- Li, Zishuo, et al.
(författare)
-
Secure State Estimation with Asynchronous Measurements against Malicious Measurement-Data and Time-Stamp Manipulation
- 2023
-
Ingår i: 2023 62nd IEEE Conference on Decision and Control, CDC 2023. - : Institute of Electrical and Electronics Engineers (IEEE). - 9798350301243 - 9798350301250 ; , s. 7073-7080
-
Konferensbidrag (refereegranskat)abstract
- This paper proposes a secure state estimation scheme with asynchronous non-periodic measurements for con-tinuous LTI systems under false data attacks on measurement transmission channels. Each sensor transmits the measurement information in a triple comprised of its sensor index, the time-stamp, and the measurement value to the fusion center via unprotected communication channels. A malicious attacker can corrupt a subset of sensors by (i) manipulating the time-stamp and the measurement value, (ii) blocking transmitted measurement triples, or (iii) injecting fake measurement triples. To deal with such attacks, we propose a secure state estimator by designing decentralized local estimators and fusing all the local states by the median operator. The local estimators receive the sampled measurements and update their local state in an asynchronous manner, while the fusion center triggers the fusion and generates a secure estimation in the presence of a local update. We prove that local estimators of benign sensors are unbiased with stable error covariance. Moreover, the fused secure estimation error has bounded expectation and covariance against at most p corrupted sensors as long as the system is 2p-sparse observable. The efficacy of the proposed scheme is demonstrated through a benchmark example of the IEEE 14-bus system.
|
|
| 8. |
- Vihriälä, Jaakko, et al.
(författare)
-
Frame Structure Design for Future Millimetre Wave Mobile Radio Access
- 2016
-
Ingår i: 2016 IEEE Globecom Workshops (GC Wkshps), 4-8 Dec. 2016. - 2166-0069.
-
Konferensbidrag (refereegranskat)abstract
- 5th generation cellular systems will extend the operation to above 6 GHz to meet extreme data rate requirements. This sets new requirements for the air interface design. In this paper, we propose several frame structure solutions from the mmMAGIC project [1], which address the challenges of using higher carrier frequencies. These solutions include subframe structures for orthogonal frequency division multiplexing (OFDM) and filter-bank multicarrier modulation (FBMC), demodulation reference signal (DMRS) design, backhauling, synchronization signal design and beam measurement reference signal design. Further research is being conducted to refine the overall frame structure solution.
|
|
| 9. |
- Xu, Yilin, et al.
(författare)
-
Analysis of Thermal Stress in a Solid Oxide Fuel Cell Due to the Sulfur Poisoning Interface of the Electrolyte and Cathode
- 2021
-
Ingår i: Energy and Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 35:3, s. 2674-2682
-
Tidskriftsartikel (refereegranskat)abstract
- The interface of an electrolyte and cathode strongly determines the oxygen reduction reaction and cell stability, but it is susceptible to sulfur impurities like SO2 in air. In this study, a 3D solid oxide fuel cell model is developed based on experimental characterization to reveal sulfur-deactivating active cathodes. The results indicate that both the average values for electric and ionic current densities drastically decrease after sulfur poisoning; meanwhile, their distributions are also changed, suggesting that the involved oxygen reduction reaction is detrimentally affected. Moreover, the temperature decreases after poisoning due to electrochemical reaction slowdown near the interface of the active cathode and electrolyte. The pronounced temperature changes together with differences in the thermal expansion coefficient of neighboring components, further resulting in uneven stress distributions at the active cathode, possibly bringing out cracks and bending. Thermal stresses are reduced after sulfur poisoning, especially for the third principal stress, which produces a decrement of 154 MPa. The visualized results of the current density, temperature, and stresses are helpful to understand the sulfur poisoning behavior and also to better understand the internal changes of some crucial electrochemical processes beneficial for further optimization of the microstructural stability.
|
|
