@article{wen_dean_floyd_franzon_2022, title={High Dimensional Optimization for Electronic Design}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85139234309&partnerID=MN8TOARS}, DOI={10.1145/3551901.3556495}, abstractNote={Bayesian optimization (BO) samples points of interest to update a surrogate model for a blackbox function. This makes it a powerful technique to optimize electronic designs which have unknown objective functions and demand high computational cost of simulation. Unfortunately, Bayesian optimization suffers from scalability issues, e.g., it can perform well in problems up to 20 dimensions. This paper addresses the curse of dimensionality and proposes an algorithm entitled Inspection-based Combo Random Embedding Bayesian Optimization (IC-REMBO). IC-REMBO improves the effectiveness and efficiency of the Random EMbedding Bayesian Optimization (REMBO) approach, which is a state-of-the-art high dimensional optimization method. Generally, it inspects the space near local optima to explore more points near local optima, so that it mitigates the over-exploration on boundaries and embedding distortion in REMBO. Consequently, it helps escape from local optima and provides a family of feasible solutions when inspecting near global optimum within a limited number of iterations.The effectiveness and efficiency of the proposed algorithm are compared with the state-of-the-art REMBO when optimizing a mmWave receiver with 38 calibration parameters to meet 4 objectives. The optimization results are close to that of a human expert. To the best of our knowledge, this is the first time applying REMBO or inspection method to electronic design.}, journal={MLCAD '22: PROCEEDINGS OF THE 2022 ACM/IEEE 4TH WORKSHOP ON MACHINE LEARNING FOR CAD (MLCAD)}, author={Wen, Yuejiang and Dean, Jacob and Floyd, Brian A. and Franzon, Paul D.}, year={2022}, pages={153–157} }
 @article{wang_tan_wen_lao_2021, title={NoPUF: A Novel PUF Design Framework Toward Modeling Attack Resistant PUFs}, volume={68}, ISSN={["1558-0806"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85103255891&partnerID=MN8TOARS}, DOI={10.1109/TCSI.2021.3067319}, abstractNote={With the rapid development and globalization of the semiconductor industry, hardware security has emerged as a critical concern. New attacking and tampering methods are continuously challenge current hardware protection methods. Combating these powerful attacks is of great importance in securing hardware devices. This paper proposes a novel framework to protect Physical Unclonable Function (PUF) against modeling attacks, denominated as Noisy PUF (NoPUF). NoPUF exploits structural unpredictability to improve overall security. We present several PUF architectures under the proposed framework that could reconfigure a conventional reliable PUF to a noisy PUF. The reconfigured PUF becomes inherently unreliable and hence achieves a higher resistance against modeling attacks. Moreover, since only a small portion of the Challenge-Response Pairs (CRPs) are required for authentication, the designer can use the information obtained from the initial reliable PUF configuration to find CRPs, which are still reliable in the noisy PUF configuration for authentication. Exploiting such information asymmetry between designer and attacker is the nexus of the proposed NoPUF design methodology. Experimental results show that we can achieve a maximum attacker and designer accuracy difference of 44.79% for a 64-stage NoPUF candidate architecture while ensuring high reliability for selected challenges.}, number={6}, journal={IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Wang, Antian and Tan, Weihang and Wen, Yuejiang and Lao, Yingjie}, year={2021}, month={Jun}, pages={2508–2521} }
 @inproceedings{wen_lao_2019, title={Efficient PUF error correction through response weighting}, volume={2018-August}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85062211649&partnerID=MN8TOARS}, DOI={10.1109/MWSCAS.2018.8623979}, abstractNote={Reliability is an important performance metric of physical unclonable function (PUF) based authentication. This paper proposes a novel methodology that incorporates error rates into PUF response error correction to improve the overall performance. The proposed method first obtains the PUF circuit parameters by using machine learning techniques, which are then used to estimate the corresponding error rates. Then, we assign PUF response bits with different degrees of error-tolerance, according to their estimated error rates. Response weighting algorithm is proposed to determine the optimal weight assignment for each PUF response bit, which is formulated as an integer optimization problem. Experimental results show that the proposed response weighting algorithm can reduce not only the false negative from 20.6% to 8.3% under a noisy environment, but also the false positive rate by 58% for a PUF-based authentication with 127-bit response and 13-bit error correction.}, booktitle={Midwest Symposium on Circuits and Systems}, author={Wen, Y. and Lao, Y.}, year={2019}, pages={849–852} }
 @inproceedings{wen_lao_2018, title={PUF Modeling Attack using Active Learning}, volume={2018-May}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85057124845&partnerID=MN8TOARS}, DOI={10.1109/ISCAS.2018.8351302}, abstractNote={Along with the rapid development of hardware security techniques, the revolutionary growth of countermeasures or attacking methods developed by intelligent and adaptive adversaries have significantly complicated the ability to create secure hardware systems. Thus, there is a critical need to (re)evaluate existing or new hardware security techniques against these state-of-the-art attacking methods. With this in mind, this paper presents a novel framework for incorporating active learning techniques into hardware security field. We demonstrate that active learning can significantly improve the learning efficiency of physical unclonable function (PUF) modeling attack, which samples the least confident and the most informative challenge-response pair (CRP) for training in each iteration. For example, our experimental results show that in order to obtain a prediction error below 4%, 2790 CRPs are required in passive learning, while only 811 CRPs are required in active learning. The sampling strategies and detailed applications of PUF modeling attack under various environmental conditions are also discussed. When the environment is very noisy, active learning may sample a large number of mislabeled CRPs and hence result in high prediction error. We present two methods to mitigate the contradiction between informative and noisy CRPs.}, booktitle={Proceedings - IEEE International Symposium on Circuits and Systems}, author={Wen, Y. and Lao, Y.}, year={2018} }
 @inproceedings{wen_lao_2018, title={Efficient fuzzy extractor implementations for PUF based authentication}, volume={2018-January}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85050857569&partnerID=MN8TOARS}, DOI={10.1109/MALWARE.2017.8323964}, abstractNote={A strong security management of digital system should take all phases of lifecycle into consideration as the adversary can simply take advantage of the weakest link to compromise the systems, regardless of software, network, or hardware. As hardware devices are becoming more and more distributed and unsupervised, hardware security has emerged as an important challenge for cybersecurity. Various techniques have been developed recently to protect systems against malicious attacks from the hardware perspective. One promising hardware security primitive that can be used for authentication or identification is the physical unclonable function (PUF), which extracts chip-unique signatures from manufacturing process variations. However, as environmental variations could affect the characteristics of digital circuits, a PUF can hardly reproduce a consistent response. In the literature, error-correcting codes and fuzzy extractors are often used to correct the PUF errors before using the generated signature for authentication. This paper proposes novel architectures that incorporate different degrees of error-tolerance into PUF response correction to improve the efficiency of PUF-based authentication. One proposed fuzzy extractor implementation improves the reliability by eliminating high-entropy PUF response bits. An alternative method is to input low-entropy bits for authentication directly, while bypassing the error-correcting block. The security can be enhanced by employing this architecture, as the probability of a random guess that could pass the authentication is reduced, while the percentage of correctable keys only decreases slightly.}, booktitle={Proceedings of the 2017 12th International Conference on Malicious and Unwanted Software, MALWARE 2017}, author={Wen, Y. and Lao, Y.}, year={2018}, pages={119–125} }
 @inproceedings{wen_lao_2017, title={Enhancing PUF reliability by machine learning}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85032692682&partnerID=MN8TOARS}, DOI={10.1109/ISCAS.2017.8050672}, abstractNote={Physical Unclonable Functions (PUFs) are promising security primitives for device authentication and key generation. This paper proposes a two-step methodology to improve the reliability of PUF under noisy conditions. The first step involves acquiring the parameters of PUF models by using machine learning algorithms. The second step then utilizes these obtained parameters to improve the reliability of PUFs by selectively choosing challenge-response pairs (CRPs) for authentication. Two distinct algorithms for improving the reliability of multiplexer (MUX) PUF, i.e., total delay difference thresholding and sensitive hits grouping, are presented. It is important to note that the methodology can be easily applied to other types of PUFs as well. Our experimental results show that the reliability of PUF-based authentication can be significantly improved by the proposed approaches. For example, in one experimental setting, the reliability of an MUX PUF is improved from 89.75% to 94.07% usmg total delay difference thresholding, while 89.30% of generated challenges are stored. As opposed to total delay difference thresholding, sensitive bits grouping possesses higher efficiency, as it can produce reliable CRPs directly. Our experimental results show that the reliability can be improved to 96.91% under the same setting, when we group 12 bits in the challenge vector of a 128-stage MUX PUF.}, booktitle={Proceedings - IEEE International Symposium on Circuits and Systems}, author={Wen, Y. and Lao, Y.}, year={2017} }
 @article{sun_wen_xu_wang_he_jiang_dai_gu_chen_2016, title={Reaction mechanism and optimal conditions for preparation of high-quality vanadium oxide films by organic sol-gel for optoelectronic applications}, volume={49}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84960157372&partnerID=MN8TOARS}, DOI={10.1088/0022-3727/49/10/105105}, abstractNote={Abstract Although vanadium oxides (VO x ) are important functional materials for academic research and industrial applications, the reaction mechanism of VO x prepared by organic sol–gel remains unclear. In order to investigate this mechanism, VO x organic sols were reacted at different temperatures, by which various VO x thin films were prepared. The products were systematically characterized by infrared spectroscopy, Raman spectroscopy, UV–vis spectroscopy, thermogravimetric analysis, scanning electron microscopy, x-ray diffraction, and a high resistance meter. Results reveal that vanadium alkoxides are created through an alcoholysis reaction of V 2 O 5 powder and isobutyl alcohol, and then a condensation reaction of the vanadium alkoxides leads to the formation of VO x networks. The as-prepared sols are strongly temperature-dependent, causing different chemical structures and physical properties for the resulting VO x films. Particularly, a moderate temperature of 110 °C prompts both alcoholysis and condensation reactions, and thus the VO x films that are produced by the sol reacted at 110 °C possess a low resistivity of 23 Ω cm, a high temperature coefficient resistance ( TCR ) of −3.2% K −1 , and a low average transmittance of 54% in 580–1100 nm, compared with those prepared by the sols reacted at lower or higher temperatures. Therefore, 110 °C is a desirable sol temperature for producing VO x films serving as high-quality bolometric materials for uncooled infrared detectors. This work discloses not only the reaction mechanism of VO x films prepared by organic sol–gel, but also the route to yield desirable VO x films for optoelectronic applications.}, number={10}, journal={Journal of Physics D: Applied Physics}, author={Sun, M. and Wen, Y. and Xu, X. and Wang, M. and He, Q. and Jiang, Y. and Dai, Z. and Gu, Y. and Chen, Z.}, year={2016} }
 @article{ao_xu_huang_jiang_yao_he_sun_wen_ma_2015, title={Control of terahertz response properties of metamaterials by dielectric layer}, volume={34}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84938055031&partnerID=MN8TOARS}, DOI={10.3724/SP.J.1010.2015.03.013}, number={3}, journal={Hongwai Yu Haomibo Xuebao/Journal of Infrared and Millimeter Waves}, author={Ao, T.-H. and Xu, X.-D. and Huang, R. and Jiang, Y.-D. and Yao, J. and He, Q. and Sun, Z.-Q. and Wen, Y.-J. and Ma, C.-Q.}, year={2015}, pages={333–339} }
 @article{xu_sun_fan_jiang_huang_wen_he_ao_2015, title={Conversion of 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium tosylate (DAST) from a Simple Optical Material to a Versatile Optoelectronic Material}, volume={5}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84937684323&partnerID=MN8TOARS}, DOI={10.1038/srep12269}, abstractNote={Abstract 4- N , N -dimethylamino-4’- N ’-methyl-stilbazolium tosylate (DAST) is an important optical material, but its poor conductivity limits applications in devices. To tackle this problem, we designed, prepared and systematically investigated novel binary composite films that are composed of two-dimensional (2D) DAST and 2D graphene. Results indicate that both electrical and optical properties of DAST can be significantly improved by graphene addition. The negative steric effects of big DAST molecules that greatly trouble ex-situ synthesis can be efficiently overcome by in-situ synthesis, thus leading to better film quality and higher physical properties. Consequently, the in-situ composite film exhibits a low sheet resistance of 7.5 × 10 6 ohm and high temperature coefficient of resistance of −2.79% K −1 , close to the levels of the most important bolometric materials for uncooled infrared detectors. Particularly, a new low temperature reduction of graphene oxide induced by DAST, which is further enhanced by in-situ process, was discovered. This work presents valuable information about the DAST–graphene composite films, their chemical structures, mechanisms, physical properties and comparison on in-situ and ex-situ syntheses of graphene–based composites, all of which will be helpful for not only theoretically studying the DAST and graphene materials and expanding their applications, but also for seeking new optoelectronic sensitive materials.}, journal={Scientific Reports}, author={Xu, X. and Sun, Z. and Fan, K. and Jiang, Y. and Huang, R. and Wen, Y. and He, Q. and Ao, T.}, year={2015} }
 @article{wen_xu_sun_he_wang_gu_jiang_dai_chen_ao_2015, title={Electrical and optical polarization responses of composite films based on aligned carbon nanotubes}, volume={5}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84945130082&partnerID=MN8TOARS}, DOI={10.1039/c5ra16110j}, abstractNote={A simple and efficient approach for large-area preparation of horizontally-aligned carbon nanotube (CNT)–vanadium oxide (VO<sub>x</sub>) composite films is presented. The as-prepared composite films particularly exhibit electrical and optical anisotropies.}, number={105}, journal={RSC Advances}, author={Wen, Y. and Xu, X. and Sun, M. and He, Q. and Wang, M. and Gu, Y. and Jiang, Y. and Dai, Z. and Chen, Z. and Ao, T.}, year={2015}, pages={86811–86816} }
 @article{huang_xu_ao_he_ma_wen_sun_jiang_2015, title={Modulation of response frequency and absorption bandwidth for terahertz metamaterials}, volume={34}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84925337447&partnerID=MN8TOARS}, DOI={10.3724/SP.J.1010.2015.00044}, number={1}, journal={Hongwai Yu Haomibo Xuebao/Journal of Infrared and Millimeter Waves}, author={Huang, R. and Xu, X.-D. and Ao, T.-H. and He, Q. and Ma, C.-Q. and Wen, Y.-J. and Sun, Z.-Q. and Jiang, Y.-D.}, year={2015}, pages={44–50} }
 @article{ma_xu_zou_liu_he_jiang_huang_wen_sun_2015, title={Study on characteristics of terahertz spectra of organic functional groups}, volume={35}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84930154547&partnerID=MN8TOARS}, DOI={10.3964/j.issn.1000-0593(2015)04-0870-05}, number={4}, journal={Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis}, author={Ma, C.-Q. and Xu, X.-D. and Zou, R.-J. and Liu, Y.-K. and He, Q. and Jiang, Y.-D. and Huang, R. and Wen, Y.-J. and Sun, Z.-Q.}, year={2015}, pages={870–874} }
 @article{ma_xu_ding_liu_luo_he_huang_wen_sun_2014, title={Characterization and simulation of far-infrared spectroscopy for saturated monohydric alcohols}, volume={34}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84898001212&partnerID=MN8TOARS}, DOI={10.3964/j.issn.1000-0593(2014)04-0952-06}, number={4}, journal={Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis}, author={Ma, C.-Q. and Xu, X.-D. and Ding, L. and Liu, Y.-K. and Luo, M.-J. and He, Q. and Huang, R. and Wen, Y.-J. and Sun, Z.-Q.}, year={2014}, pages={952–957} }
 @article{xu_huang_fan_jiang_sun_he_ao_huang_wen_ma_2014, title={Electrical and optical properties of 4-N,N-dimethylamino-4′-N′- methyl-stilbazolium tosylate (DAST) modified by carbon nanotubes}, volume={2}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84896769742&partnerID=MN8TOARS}, DOI={10.1039/c3tc32209b}, abstractNote={4-N,N-Dimethylamino-4′-N′-methyl-stilbazolium tosylate (DAST) is an important nonlinear optical and terahertz sensitive material, but its poor conductivity and extreme process for crystal growth limit practical applications. To tackle these problems, we designed and prepared novel binary composite films that are composed of two-dimensional DAST and one-dimensional carbon nanotubes (CNTs). Our preparation method is simple, reproducible, and compatible with the existing device fabrication technology. The chemical structures and physical properties of the as-prepared thin films were systematically investigated. Results indicate that the electrical conductivity and optical response in a broad region from visible light to terahertz are significantly enhanced after addition of CNTs to DAST. However, either too small or too large CNT loading in the composite will lead to degradation of the properties. In contrast, the composite film with a medium CNT content of 6.7 wt% exhibits optimal comprehensive properties that are favorable for detector applications. This work discloses valuable results about the novel DAST-based films, their chemical structures, electrical and optical properties, synergistic effects of DAST and CNTs, and a simple preparation method, all of which will be helpful for better understanding of the DAST and seeking new optoelectronic sensitive materials.}, number={13}, journal={Journal of Materials Chemistry C}, author={Xu, X. and Huang, L. and Fan, K. and Jiang, Y. and Sun, Z. and He, Q. and Ao, T. and Huang, R. and Wen, Y. and Ma, C.}, year={2014}, pages={2394–2403} }
 @article{he_xu_wen_jiang_ao_fan_huang_ma_sun_2013, title={Growth mechanism and optoelectronic properties of vanadium oxide films prepared by Sol-Gel}, volume={62}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84875634583&partnerID=MN8TOARS}, DOI={10.7498/aps.62.056802}, abstractNote={Vanadium oxide films are prepared by Sol-Gel at different annealing temperatures. Their surface morphologies, valence states, electrical and optical properties are characterized by SEM, XRD, resistance meter, UV-Vis spectrometer and FTIR, respectively. Results reveal that the optimal temperature for producing V2O5 films by Sol-gel is 430 ℃, the organics in the films cannot be decomposed completely below 430 ℃ while the V-O bonds will be broken under a higher temperature (>430 ℃). The as-prepared vanadium pentoxide films exhibit higher TCR and larger light absorption, so that they are suitable to be used as bolometric materials for uncooled infrared detectors. The growth mechanism of vanadium oxide film prepared by Sol-Gel is also presented in this paper.}, number={5}, journal={Wuli Xuebao/Acta Physica Sinica}, author={He, Q. and Xu, X.-D. and Wen, Y.-J. and Jiang, Y.-D. and Ao, T.-H. and Fan, T.-J. and Huang, L. and Ma, C.-Q. and Sun, Z.-Q.}, year={2013} }
 @article{wen_xu_he_fan_yang_huang_ao_ma_jiang_2012, title={Preparation and properties of vanadium oxide-carbon nanotube composite films}, volume={32}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84862975930&partnerID=MN8TOARS}, DOI={10.3788/AOS201232.0531002}, number={5}, journal={Guangxue Xuebao/Acta Optica Sinica}, author={Wen, Y. and Xu, X. and He, Q. and Fan, T. and Yang, S. and Huang, L. and Ao, T. and Ma, C. and Jiang, Y.}, year={2012} }