Optimal Charging of Electric Vehicles in Smart Grid: Characterization and Valley-Filling Algorithms

Electric vehicles (EVs) offer an attractive long-term solution to reduce the dependence on fossil fuel and greenhouse gas emission. However, a fleet of EVs with different EV battery charging rate constraints, that is distributed across a smart power grid network requires a coordinated charging schedule to minimize the power generation and EV charging costs. In this paper, we study a joint optimal power flow (OPF) and EV charging problem that augments the OPF problem with charging EVs over time. While the OPF problem is generally nonconvex and nonsmooth, it is shown recently that the OPF problem can be solved optimally for most practical power networks using its convex dual problem. Building on this zero duality gap result, we study a nested optimization approach to decompose the joint OPF and EV charging problem. We characterize the optimal offline EV charging schedule to be a valley-filling profile, which allows us to develop an optimal offline algorithm with computational complexity that is significantly lower than centralized interior point solvers. Furthermore, we propose a decentralized online algorithm that dynamically tracks the valley-filling profile. Our algorithms are evaluated on the IEEE 14 bus system, and the simulations show that the online algorithm performs almost near optimality ($<1$ relative difference from the offline optimal solution) under different settings.Comment: This paper is temporarily withdrawn in preparation for journal submissio

Checklist of spiders in Tasek Bera Ramsar Site, Pahang, Malaysia

Established since 1995, Tasek Bera is a wetland of international importance. It comprises an area of 31,120 hectares. It is the largest natural freshwater lake in Malaysia. The natural freshwater lake is rich in local flora and fauna. A study of the biodiversity of spider was carried out during the Biodiversity Inventory Program at Tasek Bera Ramsar Site, Pahang from 20th to 26th May 2009. Throughout the program a total of 216 spiders were collected. Among them, 13 families of spider, namely the Agelenidae, Araneidae, Lycosidae, Nephilidae, Oxyopidae, Pholcidae, Pisauridae, Psechridae, Salticidae, Sparassidae, Tetragnathidae, Theridiidae, and Thomisidae were recorded. Most spiders found on web built between branches are the members of Araneidae, Nephilidae, Psechridae, Tetragnathidae, and Theridiidae while others were either foraging on trees (Oxyopidae, Pholcidae, Pisauridae, and Salticidae) or on the ground (Agelenidae, Lycosidae, and Sparassidae). A high variety of spider species were recorded

Entangling two distant nanocavities via a waveguide

In this paper, we investigate the generation of continuous variable entanglement between two spatially-separate nanocavities mediated by a coupled resonator optical waveguide in photonic crystals. By solving the exact dynamics of the cavity system coupled to the waveguide, the entanglement and purity of the two-mode cavity state are discussed in detail for the initially separated squeezing inputs. It is found that the stable and pure entangled state of the two distant nanocavities can be achieved with the requirement of only a weak cavity-waveguide coupling when the cavities are resonant with the band center of the waveguide. The strong couplings between the cavities and the waveguide lead to the entanglement sudden death and sudden birth. When the frequencies of the cavities lie outside the band of the waveguide, the waveguide-induced cross frequency shift between the cavities can optimize the achievable entanglement. It is also shown that the entanglement can be easily manipulated through the changes of the cavity frequencies within the waveguide band.Comment: 8 pages, 8 figure

Analysis of Noise Level and Sound Transmission Loss of Noise Barrier Material for the Construction Site

The construction activities are the common noisy and annoyance work that affected the most to the human lifestyle. Those students and lecturers who stayed at the noise receptor locations might be suffering from the health impairment. The objective of this study is to assess and determine the noise level present throughout the daytime period (9AM - 12PM and 14PM - 17PM) at the respective measurement points. The analysis of noise spectrum of sound source from 125 Hz to 4 kHz is also under the topic of study. The analysis was carried out by comparing with the recommended safe noise level in term of equivalent continuous sound level (LAeq) and sound pressure level (Lp). The objective of selection the best sound transmission loss (STL) of noise barrier material among the 3 material classifications: metal, fibre and polymer is also under investigation. The experiment STL of four different types of noise barrier material was carried out in the small scale of reverberation chambers equipped with the LMS Test Lab and LMS SCADAS Mobile device. The 16 tested one-third octave frequency band which is ranged from 125 Hz to 4 kHz had been used in the experiment. The results revealed that the material of newspaper was delivered to the STL ranged from 0dB to 9.7dB within the low frequency of 125 Hz to 800 Hz. For the material of aluminium foil, it has the optimum performance with at least 5.4dB and above of STL at higher frequency ranged from 1 kHz to 4 kHz. In overall, newspaper is considered as the best noise barrier material as it could reduce the noise level more throughout the selected frequency range in this study. Even though the newspaper is insufficient durable to rain and sunlight, but it is the best noise barrier material among the 3 classifications. The experiment of material that used to cover up the newspaper which is durable to different weather will be conducted in further research

The Development of an Augmented Contrained Efficiency Framework for the Adoption of Electrionic Interorganizational Governance

Business-to-business electronic commerce provides new mechanisms for interorganizational exchange governance. This study contributes to the research of the adoption of interorganizational exchange governance by developing an augmented constrained-efficiency framework that summarizes the salient factors influencing organizational selection and adoption of electronic exchange governance. Drawing upon the literature on organizational and interorganizational governance design and adoption, the augmented constrained-efficiency framework posits that organizational selection and adoption of electronic interorganizational exchange governance are an efficiency pursuing process and also constrained by some critical forces. Internally, the constraints include organizational decision makers’ bounded rationality and organizational resources and capabilities. Externally, an organization’s institutional environments, its dependency relationship, contractual arrangements and relational norms developed with its business partners through physical transactions are important constraining forces. To demonstrate the usefulness of the augmented constrained-efficiency framework, the paper applies it to the analysis of two important modes of electronic interorganizational exchange governance, namely electronic hierarchy and electronic marketplace. By doing so, the paper sets foundations for future theory development and empirical study

Addressing a cavity with patterns at ultra-wideband detune

We demonstrate an amplified fiber ring cavity at telecommunication window addressed by optical pattern at 1.0 μm. A storage time longer than 38 μs and an ultra-wideband wavelength conversion of ~500 nm have been obtained. © 2015 OSApostprin

Tafazzin regulates human conjunctiva epithelial cell proliferation via inhibiting TGFβ signaling pathway

Molecular Vision181402-1410MVEP

60-MHz wavelength-encoded tomography (WET)

Paper JW2A.82Wavelength-encoded tomography (WET) is upgraded to a triple-time-lens system to perform ultrafast cross-sectional imaging through 68.4x-temporal magnification. 60-MHz A-scan rate is demonstrated by imaging a glass sample with 180-μm axial resolution. © 2015 OSApostprin