Gains in the Life-Cycle of Adaptable, Self-Organizing Material Handling Systems

Compared to conventional material flow controls, self-organized material handling systems and the Internet of Things in facility logistics promise several advantages during the life-cycle. Most important is the increased adaptability in case of expansions or modifications due to a consistent modular design; this also promotes an increased robustness due to clearly defined interfaces and a decreased complexity of each module. The use of RFID technology increases the availability of real-time data about the system and the transported units. However, the introduction of self-organized material handling systems also causes costs, e.g. for necessary RFID tags and readers. Against this background, it is unsatisfactory that the increased adaptability as the main advantage of these systems is hard to grasp. This paper proposes a methodology to analyze the advantages of adaptability in facility logistics during the life-cycle of a material handling system and illustrates its usage. The proposed methodology is based on a dynamic optimization of payoffs during the life-cycle; thereby, all payoffs which are influenced by the adaptability of the material-handling system are included; therefore, the methodology allows to consider the adaptability of all material handling systems

Comparison of reconfigurable structures for flexible word-length multiplication

Binary multiplication continues to be one of the essential arithmetic operations in digital circuits. Even though field-programmable gate arrays (FPGAs) are becoming more and more powerful these days, the vendors cannot avoid implementing multiplications with high word-lengths using embedded blocks instead of configurable logic. But on the other hand, the circuit's efficiency decreases if the provided word-length of the hard-wired multipliers exceeds the precision requirements of the algorithm mapped into the FPGA. Thus it is beneficial to use multiplier blocks with configurable word-length, optimized for area, speed and power dissipation, e.g. regarding digital signal processing (DSP) applications. <br><br> In this contribution, we present different approaches and structures for the realization of a multiplication with variable precision and perform an objective comparison. This includes one approach based on a modified Baugh and Wooley algorithm and three structures using Booth's arithmetic operand recoding with different array structures. All modules have the option to compute signed two's complement fix-point numbers either as an individual computing unit or interconnected to a superior array. Therefore, a high throughput at low precision through parallelism, or a high precision through concatenation can be achieved

Configurable blocks for multi-precision multiplication

Implementing arithmetic-heavy applications such as filters or neural networks in FPGAs relies to a great extent on the realization of efficient multipliers. However, implementing high-precision multipliers only with configurable logic leads to a large lookup-table usage and considerable routing efforts. Thus, hard-wired multiplier blocks are embedded in modern FPGA devices in order to relieve the resources, but their word-length is still fixed to e.g. 18×18-bit in the Xilinx Virtex-IV DSP48 slices. In this paper, we describe our approach of creating configurable blocks suitable for multi-precision multiplication with a word-length that can be changed at runtime. We present a novel block-serial design that shows a 60% area advantage over a fully parallel multiplier and also a larger structure that can be partitioned into several fully functional smaller multipliers working simultaneously in different configurations. © 2008 IEEE

GHOST - a novel airborne gas chromatograph for in situ measurements of long-lived tracers in the lower stratosphere : method und Applications

A novel fully-automated airborne gas chromatograph for in situ measurements of long-lived stratospheric tracers has been developed, combining the high selectivity of a megabore PLOT capillary column with recently developed sampling and separation techniques. The Gas cHromatograph for the Observation of Stratospheric Tracers (GHOST) has been successfully operated during three STREAM campaigns (Stratosphere TRoposphere Experiment by Airborne Measurement) onboard a Cessna Citation II aircraft in two different modes: Either N2O and CF2Cl2 (CFC-12) or CFC-12 and CFCl3 (CFC-11) have been measured simultaneously, with a time resolution of 2 min for both modes. Under flight conditions the instrument precision (1 sigma) for these species is better than 0.9%, and the accuracy (1 sigma) is better than 2.0% of the tropospheric values of all measured compounds. The detection limits (3 sigma) are below 28 ppb for N2O, 14 ppt for CFC-12, and 8 ppt for CFC-11, respectively, i.e., well below 10% of the tropospheric values of all measured compounds. Post-mission optimization of the chromatographic separation showed a possible enhancement of the time resolution by up to a factor of 2, associated with a comparable increase in precision and detection limit. As test of actual performance of GHOST results from an in-flight N2O intercomparison with a tunable diode laser absorption spectrometer (TDLAS) are presented. They yield an excellent agreement between both instruments. Furthermore, on the basis of the hitherto most extensive set of upper tropospheric and lower stratospheric data, the relative stratospheric N2O lifetime is re-assessed. When referenced to the WMO reference CFC-11 lifetime of 45 +/- 7 years an N2O lifetime of 91 +/- 15 years is derived, a value substantially smaller than the WMO reference lifetime of 120 years. Moreover, this value implies a stratospheric N2O sink strength of 16.3 +/- 2.7 Tg (N) yr(-1) which is 30% larger than previous estimates

Low Self-control, Harassment Perpetration, and Stalking Victimization among Asian College Students

A sizable amount of research has empirically tested Gottfredson and Hirschi’s general theory of crime, with results showing that low self-control is an important correlate of offending, analogous behaviors, and victimization. Within this line of research however, less attention has been paid toward examining the generality of their theory within the race/ethnicity space as well as the extent to which the theory offers a useful framework for understanding harassment and stalking. In this paper, we use data from a sample of young adult Asian Americans to examine these outcomes. Unlike prior research, we do not detect any relationship between low self-control on harassment or stalking. Implications and directions for future research are outlined