1,160 research outputs found
Fast design optimization of UWB antenna with WLAN Band-Notch
In this paper, a methodology for rapid design optimization of an ultra-wideband ( UWB) monopole antenna with a lower WLAN band-notch is presented. The band-notch is realized using an open loop resonator implemented in the radiation patch of the antenna. Design optimization is a two stage process, with the first stage focused on the design of the antenna itself, and the second stage aiming at identification of the appropriate dimensions of the resonator with the purpose of allocating the band-notch in the desired frequency range. Both optimization stages are realized using surrogate-based optimization involving variable-fidelity electromagnetic ( EM) simulation models as well as an additive response correction ( first stage), and sequential approximate optimization ( second stage). The final antenna design is obtained at the CPU cost corresponding to only 23 high-fidelity EM antenna simulations
Agriculture Study Abroad program to Poland
The Technology Travel Course (TSM 496) is an elective course that meets the university-wide international perspectives requirement. The course has a curricular home in the department of Agricultural and Biosystems Engineering (ABE), Iowa State University (ISU). It enables instructors to develop and offer a study abroad program structured as a faculty-led trip abroad. This course is also an excellent opportunity for students to learn/compare technology concepts and applications in an international context that is encouraged by the ABE External Advisory Board. The objectives of this paper are to (1) Review the application of TSM 496 to Ag Study Abroad trip to Poland (with cultural trips to Czech Republic, Denmark, Germany, Lithuania, and Ukraine, and to (2) summarize curricular enhancement of student learning objectives (SLOs) and competencies. The course has been offered yearly since 2011, and served 48 students from several majors in Agriculture & Life Sciences and Engineering colleges. The pre-departure course is focused on teaming up ISU students with students at two agricultural universities in Poland. Teams develop comparative projects focused on agriculture with specific emphasis on animal systems production, technology, environment, sustainability, and regulations. Projects are finalized and presented jointly at special Polish-American Student Workshops. The joint project format creates an opportunity to make friends with students in Poland while working on international projects. The scientific part of the program is a mix of field trips to farms, plants, co-ops, lab tours, cultural sites and activities. Students have many opportunities to socialize, get inspired by rich culture, history, science, agro business attitudes and the spirit of change. SLOs are measured with the program surveys. Currently 65 SLOs/competencies are enhanced with 17 provided by this program (26%). In addition, 25 new competencies are gained, a 38% increase to the new total of 90. Students highly rate this learning and often list it as a highlight of their college career thus far. Data analysis of the Program Evaluation Surveys shows high degree of developing student skills, meeting and enhancement of class goals, departmental and college SLOs
2017 update - Air Quality Laboratory & Olfactometry Laboratory Equipment - Koziel\u27s Lab
EQUIPMENT
Major equipment in Dr. Koziel’s laboratory ([email protected]) see reference list below for complete descriptions of equipment used in previous research.
For odorous VOC gas quantification: VOCs: Agilent 6890 GC-MS-FID-PID (5975C) VOCs: multidimensional GC-MS-Olfactometry (based on Agilent GC-MS platform) equipped with thermal desorption for sorbent tubes. NH3 and H2S (Drager electrochemical portable meter). INNOVA (NH3, CO2) Greenhouse gas GC-FID-ECD (for CO2, CH4, and N2O
Effects of Architecture on Information Leakage of a Hardware Advanced Encryption Standard Implementation
Side-channel analysis (SCA) is a threat to many modern cryptosystems. Many countermeasures exist, but are costly to implement and still do not provide complete protection against SCA. A plausible alternative is to design the cryptosystem using architectures that are known to leak little information about the cryptosystem\u27s operations. This research uses several common primitive architectures for the Advanced Encryption Standard (AES) and assesses the susceptibility of the full AES system to side-channel attack for various primitive configurations. A combined encryption/decryption core is also evaluated to determine if variation of high-level architectures affects leakage characteristics. These different configurations are evaluated under multiple measurement types and leakage models. The results show that different hardware configurations do impact the amount of information leaked by a device, but none of the tested configurations are able to prevent exploitation
Multicolour photometry of Balloon 090100001: linking the two classes of pulsating hot subdwarfs
We present results of the multicolour UBVR photometry of the high-amplitude
EC14026-type star, Balloon 090100001. The data span over a month and consist of
more than a hundred hours of observations. Fourier analysis of these data led
us to the detection of at least 30 modes of pulsation of which 22 are
independent. The frequencies of 13 detected modes group in three narrow ranges,
around 2.8, 3.8 and 4.7 mHz, where the radial fundamental mode, the first and
second overtones are likely to occur. Surprisingly, we also detect 9
independent modes in the low-frequency domain, between 0.15 and 0.4 mHz. These
modes are typical for pulsations found in PG1716+426-type stars, discovered
recently among cool B-type subdwarfs. The modes found in these stars are
attributed to the high-order g modes. As both kinds of pulsations are observed
in Balloon 090100001, it represents a link between the two classes of pulsating
hot subdwarfs. At present, it is probably the most suitable target for testing
evolutionary scenarios and internal constitution models of these stars by means
of asteroseismology.
Three of the modes we discovered form an equidistant frequency triplet which
can be explained by invoking rotational splitting of an = 1 mode. The
splitting amounts to about 1.58 Hz, leading to a rotation period of 7.1
0.1 days.Comment: 12 pages, 14 figures, accepted for publication in MNRAS. For
full-resolution postscript file, visit
http://www.as.wsp.krakow.pl/~andy/balloon.ps.g
Cost-efficient modeling of antenna structures using Gradient Enhanced Kriging
Reliable yet fast surrogate models are indispensable in the design of contemporary antenna structures. Data-driven models, e.g., based on Gaussian Processes or support-vector regression, offer sufficient flexibility and speed, however, their setup cost is large and grows very quickly with the dimensionality of the design space. In this paper, we propose cost-efficient modeling of antenna structures using Gradient-Enhanced Kriging. In our approach, the training data set contains, apart from the EM-simulation responses of the structure at hand, also derivative data at the respective training locations obtained at little extra cost using adjoint sensitivity techniques. We demonstrate that introduction of the derivative information into the model allows for considerable reduction of the model setup cost (in terms of the number of training points required) without compromising its predictive power. The Gradient-Enhanced Kriging technique is illustrated using a dielectric resonator antenna structure. Comparison with conventional Kriging interpolation is also provided
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