| 21. |
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| 22. |
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| 23. |
- Månsson, Daniel, 1979-
(author)
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Intentional electromagnetic interference (IEMI) : Susceptibility investigations and classification of civilian systems and equipment
- 2008
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Doctoral thesis (other academic/artistic)abstract
- This PhD thesis addresses the threat posed to society by sources that can produce high power electromagnetic pulses (HEPM) and be used maliciously to disturb or damage electronic equipment. The vulnerability from intentional electromagnetic interference (IEMI) has increased in the recent decades due to the widespread dependence of the civil society on sensitive electronic systems and proliferation of radiation sources. As the characteristics of the disturbances associated with IEMI often have very high frequency content, the existing mitigation measures and protection components may not be adequate. It was seen that for ultra wideband (UWB) transients low voltage protection components may not work as intended, due to parasitic components that arises from the packaging of the device. The large spatial distribution of many civilian facilities and critical infra-structures (e.g., power generation, communications, train system, etc.) presents many unexpected ports for an attacker as the majority of the parts of these systems are not protected or secure. As the new European Rail Traffic Management System (ERTMS) will utilize wireless communication for communication and control of the trains the vulnerability from different radiating HPEM sources was investigated. Angles of incidence and frequencies that are a threat in a given situation are identified. Due to the possibility of unexpected ports, the propagation of differential mode ultra wideband transients in low voltage power networks, when injected into a power socket of a facility, was studied. The effects on the transient propagation from cable bends, switches and junctions were studied, both in a laboratory setup and in the network of a facility. Also, as modern electronic equipment and systems may not be tested for waveforms and disturbances other than standardized EMC tests, experiments on some common commercial-off-the-shelf (COTS) equipment were performed with non-standard test situation. It was seen that these could easily be disturbed or even permanently damaged. In addition, due to the inherent difficulties with IEMI, a new method for classifying facilities from IEMI is suggested. It is based on available terminology of accessibility (A), susceptibility (S) and consequence (C), but expands these and forms the so called IEMI/ASC-cube.
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| 24. |
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| 25. |
- Nyström, Olle, 1979, et al.
(author)
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Optics Design and Verificatgion for the APEX Swedish Heterodyne Facility Instrument (SHeFI)
- 2009
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In: Journal of Infrared, Millimeter, and Terahertz Waves. - : Springer Science and Business Media LLC. - 1866-6892 .- 1866-6906. ; 30:7, s. 746-761
-
Journal article (peer-reviewed)abstract
- In this paper, we present the design and verification of the optics of the Swedish Heterodyne Facility Instrument (SHeFI) receiver installed in the Atacama Pathfinder EXperiment (APEX) telescope during spring 2008. SHeFI is located in the Nasmyth instrumentation Cabin A (NCA). The receiver has been designed to have 6 frequency channels, of which four receiver channels have been built, and characterized: 211-275 GHz(Band 1), 275-370 GHz (Band 2), 385-500 GHz (Band 3), and 1250-1390 GHz (Band T2). Bands 1, 2, and T2 are installed at the telescope and are currently in operation. The optical design is driven by the requirement of frequency independent illumination of the secondary with -12 dB edge taper for each frequency channel and the limitation (beam clearance through the Nasmyth tube and the elevation encoder) imposed by the receiver position in the NCA. This paper describes the design approach, optimization, and verification of the optical system, coupling each individual receiving beam to the common optics of the telescope.
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| 26. |
- Piscator, Johan, 1977, et al.
(author)
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Multiparameter admittance spectroscopy for metal-oxide-semiconductor systems
- 2009
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 106:5, s. 054510-
-
Journal article (peer-reviewed)abstract
- Admittance spectroscopy is extended for measuring capacitance and conductance on metal-oxide-semiconductor (MOS) structures as a function of gate voltage, frequency, and temperature. An automatic setup has been designed for collecting data along these dimensions in one measurement cycle. The theory for admittance spectroscopy has been developed by starting from basic charge carrier statistics. Using numerical integration of energy dependent parameters instead of the commonly used analytical solution, conductance dispersion curves are obtained which do not need to be adjusted by assuming lateral surface potential variations at the oxide-semiconductor interface. Also, we find that interface state densities extracted by using traditional methods are four times lower than those obtained by using our theory. Experimental data presented in three-dimensional plots are compared with theoretical calculations, revealing the possibilities and limitations of the conductance method.
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| 27. |
- Rafique, Raihan, 1978, et al.
(author)
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RSFQ based microwave controller for qubit
- 2007
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In: 11th International Superconducting Electronics Conference, Washington DC, USA, June 10-14, 2007.. ; 11, s. P-U05
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Conference paper (other academic/artistic)abstract
- We present a Rapid Single Flux Quantum (RSFQ) microwave controller for superconducting qubits. Applying microwaves from room temperature sources is the conventional approach to excite quantum state transitions. Finding a method to apply short microwave bursts with a narrow linewidth is a challenge for on-chip Josephson based oscillators. We present a scheme containing an RSFQ pulse generator, ultra narrowband filter, SQUID based resonator and coupler. The operating frequency of the designed controller is 3-6 GHz. The unique feature of this design is a SQUID based resonator. By varying magnetic field in the SQUID, theresonance length can be varied between λ/4 and λ/2. Theresonator is added as a shunt between the filter and coupler. Transmission of microwave signals from the filter to the output is determined by the shunt resonance. RSFQ T flip-flop circuit is designed to control the magnetic field applied to the SQUID in the resonator. Miniaturization of the coupler of 2-10 GHz has been done using a quasi-lumped element designed. We present the simulations results for the frequency response ofdifferent resonance lengths of the modulator.
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| 28. |
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| 29. |
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| 30. |
- Brandt, Eva, et al.
(author)
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Design Lab : re-thinking what and how to design
- 2005
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In: Design spaces. - Helsingfors : Edita Publishing Oy. ; , s. 34-43
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Book chapter (other academic/artistic)abstract
- Over the last decades there has been a dramatic change in the design agenda within the field of IT design. With the increase of mobile and wireless devices and the massive expansion of Internet availability the classic object of design - is about to vanish. Even if we conceive the setting where information technology is used as a 'system', this system can hardly be seen as the outcome of a system design process. Arguably, IT design is today guided by new design agendas. Ubiquitous computing and from the user side information ecologies seem to be more appropriate labels for the emerging technology. The objects of design has correspondingly been changing from systems to devices, tools or information appliances. This radical opening of the question of what to design has led to an apparent confusion on how to design. Just as the field of information systems is about to mature with a broad and widely accepted repertoire of design approaches and methods, ranging from workflow analysis to user involvement, this battery of approaches is loosing ground in favor of more techno-centric explorations, such as Tangible Computing. In our view there seem to be a growing divide between mainly North American contributions to IT design emphasizing new information technology concepts such as ubiquitous computing, tangible interaction and augmented reality, and mainly European contributions emphasizing the role of particular information technology applications in the light of in-depth studies of the potential contexts of use.
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