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As a part of the LDTA 2011 Tool Challenge, we implemented a compiler for the language Oberon-0 using the metacompilation tool JastAdd. In this paper, we report on this implementation, and reflect on aspects of it such as ease of use, modularity, and safety.
This paper addresses a problem related to control of web servers. Due to architectual issues, relevant measurements can only be taken over a limited part of the server system, which leaves the controller unaware of what happens in buffers proceeding the actual web-server (for instance, in the TCP/IP layers). In earlier presented work we modeled such a system and proved that the unmeasured bufferin
We consider detection over intersymbol interference channels that are unknown at the receiver. For such a kind of systems, we consider an alternative approach to the design of a reduced-complexity receiver based on channel shortening without the explicit estimation of the channel impulse response. The proposed solution allows a simplification of the receiver architecture and a faster convergence f
Using the metric of channel capacity, three dual-antenna multiple-input multiple-output (MIMO) terminals with adaptive impedance matching were evaluated at LTE Band 13 in four different user scenarios using simulation. Each of the three terminals is equipped with a slot-monopole antenna and a planar inverted-F antenna (PIFA). The slot monopole is fixed at one edge of the chassis, whereas the locat
This paper presents a decoder for multi-carrier modulated signals employing Faster-than-Nyquist (FTN) signaling. FTN signaling is a method of improving bandwidth efficiency at the expense of higher processing complexity in the transceiver. The decoder can switch between orthogonal and FTN signaling modes and exploits channel properties to improve bandwidth efficiency. The decoder is fabricated in
We still have limited knowledge about the underlying genetic mechanisms that enable migrating species of birds to navigate the globe. Here we make an attempt to get insight into the genetic architecture controlling this complex innate behaviour. We contrast the gene expression profiles of two closely related songbird subspecies with divergent migratory phenotypes. In addition to comparing differen
In the paper we consider a commonly known network design problem with demand restoration assuming stub release. No compact linear programming (LP) formulation for the problem is known, and all known non-compact LP formulations of the problem require NP-hard path generation (pricing). Therefore, the problem itself is suspected to be NP-hard - this, however, is not actually known. The main result of
A procedure for guaranteed cost control design of delayed linear bilateral teleoperation systems with nonlinear external forces is proposed. The assumption that the external forces are nonlinear functions of velocities and/or positions of local devices, and one part of these forces satisfies a sector condition has been made. A virtual tool system is introduced to 'observe' the forces at the remote
Reference attributed grammars (RAGs) extend Knuth’s attribute grammars with references. These references can be used to extend the abstract syntax tree to a graph. We investigate how RAGs can be used for implementing tools for visual languages. Programs in those languages can often be expressed as graphs.
This paper presents a low voltage continuous-time delta-sigma modulator (DSM) intended for the receiver of an ultra-low-power radio. The DSM features a 2nd-order loop filter implemented with a single operational amplifier to reduce the power consumption. Furthermore, a 4-bit quantizer is used to achieve high resolution while keeping the sampling frequency low. The quantizer is realized using the s
Gm-C filters suffer from limited dynamic range due to a trade-off between noise and linearity in OTA design. This paper therefore presents a filter with a linearization technique to break this trade-off. This technique is demonstrated by a low power 4th order 10MHz Butterworth Gm-C low pass filter. The filter was implemented in 65nm CMOS technology with a core area of 0.19mm2 and a total current c
Abstract in UndeterminedThe radio channels between nodes of an indoor peer-to-peer network show specific fast fading characteristics. Depending on the mobility and on the scattering properties of the environment, different kinds of fading distributions can occur: Ricean fading between static nodes, but also Rayleigh or even double-Rayleigh fading between mobile nodes. We investigate fast fading in
Background. Software engineering is in search for general principles that apply across contexts, for example to help guide software quality assurance. Fenton and Ohlsson presented such observations on fault distributions, which have been replicated once. Objectives.We intend to replicate their study a second time in a new environment. Method.We conducted a close replication, collecting defect data
Manipulation tasks are characterized by continuous motion trajectories containing a set of key phases. In this paper, we propose a probabilistic method to autonomously segment the motion trajectories for estimating the key phases embedded in such a task. The autonomous segmentation process relies on principal component analysis to adaptively project into one of the low-dimensional subspaces, in wh
Partially Premixed Combustion (PPC) is an internal combustion engine concept that aims to yield low NOx and soot emission levels together with high engine efficiency. PPC belongs to the class of low temperature combustion concepts where the ignition delay is prolonged in order to promote the air-fuel-mixture homogeneity in the combustion chamber at the start of combustion. A more homogeneous combu
We consider the problem of network formation in a distributed fashion. Network formation is modeled as a strategic-form game, where agents represent nodes that form and sever unidirectional links with other nodes and derive utilities from these links. Furthermore, agents can form links only with a limited set of neighbors. Agents trade off the benefit from links, which is determined by a distance-
In the paper we present integer programming (IP) optimization models for flexgrid elastic optical networks (EON). We consider several different basic assumptions regarding flexibility of EON that lead to a variety of IP formulations differing in precision and complexity. As usual, detailed models aiming at precisely describing technological aspects of EON suffer from tractability issues resulting
