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931.
Sara Lise Jeppesen 《Systemic Practice and Action Research》2011,24(2):133-146
The aim of this paper is to explore an explicit use of the concept of sustainability within transport planning. This paper
analyses the concept of sustainability based on a practical approach for a sustainable development of Nordhavn, an area of
Copenhagen, exemplifying a complex planning problem. An exploration of the application of the concept of sustainability is
carried out using elements of Soft Systems Methodology (SSM). This approach indicates a need to separate the use of sustainability
considerations regarding the transport planning ‘process’ from the transport planning ‘results’. The two approaches are related
to the planning levels presented by Ulrich (Syst Prac 1(4):415–428, 1988). It was chosen to focus on the understanding of a sustainable transport planning process. This focus is addressed by four
stakeholder groups interviewed based on the ‘ought to’ mode of Critical Systems Heuristics (CSH). Finally an outline of some
of the factors of a sustainable transport planning process is proposed. 相似文献
932.
The CLC protocol (proposed by Tzung-Her Chen, Wei-Bin Lee and Hsing-Bai Chen, CLC, for short) is a new three-party password-authenticated
key exchange (3PAKE) protocol. This CLC protocol provides a superior round efficiency (only three rounds), and its resources
required for computation are relatively few. However, we find that the leakage of values A
V
and B
V
in the CLC protocol will make a man-in-the-middle attack feasible in practice, where A
V
and B
V
are the authentication information chosen by the server for the participants A and B. In this paper, we describe our attack on the CLC protocol and further present a modified 3PAKE protocol, which is essentially
an improved CLC protocol. Our protocol can resist attacks available, including man-in-the-middle attack we mount on the initial
CLC protocol. Meanwhile, we allow that the participants choose their own passwords by themselves, thus avoiding the danger
that the server is controlled in the initialization phase. Also, the computational cost of our protocol is lower than that
of the CLC protocol. 相似文献
933.
Using FLAC3D numerical simulation software,the influence laws that the different mining depth,mining width and filling step have on the surface subsidence and horizontal movement under the condition of filling mining has been studied.The functional relation among full subsidence and horizontal movement of surface,mining depth,mining width and filling step has been given,which provides theoretical formulas been referenced for filling mining theory and has a certain guiding value. 相似文献
934.
In this paper,domain decomposition method(DDM) for numerical solutions of mathematical physics equations is improved into dynamic domain decomposition method(DDDM) . The main feature of the DDDM is that the number,shape and volume of the sub-domains are all flexibly changeable during the iterations,so it suits well to be implemented on a reconfigurable parallel computing system. Convergence analysis of the DDDM is given,while an application approach to a weak nonlinear elliptic boundary value problem and a ... 相似文献
935.
Within the framework of the regularization theory, a spectral regularization method is introduced and analyzed. The convergence estimate under an appropriate choice of regularization parameter is obtained. A numerical implementation is described. Numerical examples show that the proposed method is effective and stable. 相似文献
936.
High-speed all-optical logic circuits have attracted much attention because of their important roles in signal processing in next-generation optical networks.The digital encoder is widely used in binary calculation,multiplexing,demultiplexing,address recognition and data encryption.A priority encoder allows the existence of multiple valid inputs simultaneously,identifies the priority of the request signals and encodes the priority.We propose and experimentally demonstrate an all-optical 4-bit priority encoder for return-to-zero signals at 40 Gbit/s based on cross-gain modulation in semiconductor optical amplifiers.Detuning fil-ters after semiconductor optical amplifiers are employed to improve the output performance.Correct logic bit sequences and clear open eye patterns with extinction ratios exceeding 10 dB are achieved. 相似文献
937.
The approach of available transfer capability (denoted as ATC) incorporating wind generation has been paid very high attention
since the development of wind generation. Based on the maximum function, this paper presents an ATC model. The characteristic
of the new model is twofold. First, it considers wind turbines connected to power system and static security of power system
simultaneously. Second, it is a system of semismooth equations and can be solved easily. By using the smoothing strategy,
a smoothing Newton method is adopted for solving the proposed new ATC model. Numerical simulation results of the IEEE 30-bus
and 118-bus system show that the new model and algorithm are feasible and effective. The impact of wind turbines connected
to power system on ATC is also analyzed. 相似文献
938.
Mobile genomic islands (GIs) can be excised from the chromosome, then form a circular intermediate and be reintegrated into
the chromosome by the GI internal integrase. Some mobile GIs can also be transferred into a new receptor cell by transformation,
conjugation, or transduction. The action sites of the integrase are usually flanked direct repeats (DRs) of the GIs. Accurate
localization of the flanking sequences is a precondition for determining the mobility of the GI. Mobile GIs are generally
associated with transfer RNAs (tRNAs). Based on the correlation between flanking sequences and tRNA sequences, the flanking
sequences of 11 putative mobile GIs in Pseudomonas aeruginosa PAO1, P. aeruginosa PA14, P. fluorescens Pf-5 and P. fluorescens Pf0-1 were identified. Among the 11 GIs, Pf0-1GI-1 is responsible for benzoate degradation. PAO1GI-1, Pf5GI-2, Pf5GI-3, and
Pf5GI-4 were confirmed experimentally to be excised from a chromosome to form a circular intermediate. The action sites of
the integrases are these GIs direct repeats. Due to distinct DRs, cutting sites for the internal integrase of PAO1GI-1, Pf5GI-2,
Pf5GI-3 and Pf5GI-4 were determined outside the T-loop of the tRNAGly gene, outside the anticodon loop of the tRNASer gene and tRNALys gene, and at the asymmetric 3′-end of the tRNALeu gene, respectively. PAO1GI-1 and other mobile GIs may be transferred into many different strains that belong to different
phyla because of the clear flanking sequences. This study describes basic information about the action sites of the integrases,
assesses the mobility of GIs, and can help design and transfer mobile GIs to candidate strains. 相似文献
939.
The shock compression experiment of liquid helium is an available way to gain properties of specimen at high temperatures and pressures.Based on Fluent,a thermal insulation analysis and design of a liquid helium temperature target in the environment condition of 100 Pa for shock compression experiment is performed.Then,a cryogenic target with a 10 K helium vapor shield and a separated vacuum interval is particularly developed.A lowest temperature of 3.63 K and a stable temperature of 3.70 K in the specimen cavity with an accuracy of 0.1 K are obtained by means of continuous flow and vacuum cooling.Both time-consuming and temperature stability are well-suited to the requirements of the shock compression experiment.The results show that the calculated and experimental data well-matched each other.The simulation method may be effective and feasible for the optimal design of the cryogenic target. 相似文献
940.
DNA damage,signaling and repair: Protecting genomic integrity and reducing the risk of human disease
PingKun Zhou 《科学通报(英文版)》2011,56(30):3119-3121
DNA is the genetic material that contains the "instructions" to not only guide the continuation of life but also govern the development, metabolism and functioning of living organisms. DNA damage occurs daily due to various exogenous (environ- 相似文献