A survey of sag monitoring methods for power grid transmission lines

The transmission line is a fundamental asset in the power grid. The sag condition of the transmission line between two support towers requires accurate real-time monitoring in order to avoid any health and safety hazards or power failure. In this paper, state-of-the-art methods on transmission line sag monitoring are thoroughly reviewed and compared. Both the direct methods that use the direct video or image of the transmission line and the indirect methods that use the relationships between sag and line parameters are investigated. Sag prediction methods and relevant industry standards are also examined. Based on these investigation and examination, future research challenges are outlined and useful recommendations on the choices of sag monitoring methods in different applications are made

Criteria of evaluating initial model for effective dynamic model updating

Finite element model updating is an important research field in structural dynamics. Though a variety of updating methods have been proposed in the past decades, all the methods could be effective only on the assumption that the initial finite element model is updatable. The assumption has led to the fact that many researchers study on how to update the model while little attention is paid to studies on whether the model is updatable. This has become inevitable obstacle between research and engineering applications because the assumption is not a tenable hypothesis in practice. To circumvent this problem, the evaluation of model updatability is studied in this paper. Firstly, two conditional statements about mapping are proved as a theoretical basis. Then, two criteria for evaluation of initial models are deduced. A beam is employed in the numerical simulations. Two different initial models for the beam are constructed with different boundary conditions. The models are evaluated using the proposed criteria. The results indicate that the criteria are able to distinguish the model updatability

A Crowdsourcing Mode of Tourism Customization Based on Sharing Economy

China’s latest innovations of Internet Economy are partly reflected in video living broadcast, shared bicycles etc. In recent years, tourism industry in China obtains rapid development by utilizing Internet. However, it is still difficult to meet the growing tourist demands. In order to solve this problem, in this paper, we put forward a Tourism Crowdsourcing Model (TCM), which utilizes the public creativity to meet the increasing demands for personalized tourism. Firstly, the main problems of the tourism industry are analyzed. Secondly, the pattern of TCM is elaborated, and a matching algorithm between the tourist requirements and the workers’ abilities is well designed to find the qualified service providers efficiently and accurately. Finally, an example is given to verify the feasibility and effectiveness of the TCM based on shared economy. The results shows that TCM has some significant advantages to satisfy the tourism personalized needs by motivating the public to participate in the tourism industry initiatively

Razvoj proteolitičkih komponenata okusa tradicionalnoga kineskog predjela dobivenog fermentacijom soje (douchiba)

Douchiba, a traditional Chinese soy-fermented appetizer, has been abundantly produced and widely consumed in Guizhou province of Southwest China. In this study, analysis of low-molecular mass peptide fractions, hydrophobic bitter peptide fractions, and free amino acid (FAA) profiles was conducted to understand the changes in tasty components of douchiba during five consecutive stages of its manufacture: steamed soybean (SS), 5-day incubated douchi qu (DQ), 6-month fermented douchi (DC), semi-finished douchiba (sm-DCB), and 6-month ripened douchiba as a finished product (DCB). Results indicated that the ratio of potentially taste-active oligopeptides (500–1000 Da) accounted for 13.98 and 2.54 % of low-molecular mass peptide fractions and hydrophobic bitter peptide fractions at DCB stage, respectively. The evolution patterns of total free amino acids (TFAA) increased significantly (p<0.05) from SS to DCB by about 11 times and amounted to 20.14 % of crude protein. At the end of the ripening period (6 months), Arg, Glu, Phe, Leu, and Lys were the most abundant FAA, adding up to 64.37 % of TFAA. The most abundant tasty FAA class was bitter FAA, about 8-and 3-fold higher than the content of sweet and monosodium glutamate (MSG)-like FAA, respectively. The final values of all bitter and MSG-like FAA at DCB stage were significantly higher than their respective thresholds. However, the final characteristic taste of douchiba was predominated by saltiness, followed by moderate umami taste and slight bitterness, possibly as a result of the balance and interaction among different tasty components.Douchiba, tradicionalno kinesko predjelo dobiveno fermentacijom soje, u velikim se količinama proizvodi i koristi u provinciji Guizhou u jugozapadnom dijelu Kine. U ovom radu istražene su peptidne frakcije male molekularne mase, hidrofobne frakcije peptida koje pridonose gorčini proizvoda i profili slobodnih aminokiselina (free amino acid – FAA) za bolje razumijevanje uzroka promjene okusa tijekom 5 uzastopnih faza proizvodnje: parenog zrna soje (steamed soybean – SS), proizvoda dobivenog nakon 5 dana inkubacije (douchi qu – DQ), proizvoda dobivenog fermentacijom tijekom 6 mjeseci (DC), poluproizvedene douchibe (sm-DCB) i gotovog proizvoda dobivenog nakon 6 mjeseci zrenja (DCB). Rezultati pokazuju da je omjer potencijalno aktivnih oligopeptida (500-1000 Da) i frakcije peptida male molekularne mase te hidrofobnih peptida koji daju gorčinu proizvodu DCB iznosio 13,98 i 2,54 %. Razvojni uzorak ukupnih slobodnih aminokiselina (total free amino acids – TFAA) značajno se povećao (p<0,05) proizvodnjom DCB iz SS (otprilike 11 puta) i iznosio je 20,14 % sirovih proteina. Pri kraju zrenja (nakon 6 mjeseci) bilo je najviše slobodnih aminokiselina Arg, Glu, Phe, Leu i Lys, i to od 64,37 % TFAA. Od komponenata okusa najviše je bilo FAA koje daju gorčinu proizvodu, 8 puta više nego slatkastih te 3 puta više od FAA sličnih mononatrijevu glutamatu (monosodium glutamate – MSG). Konačne vrijednosti svih gorkastih FAA i onih sličnima MSG u proizvodu DCB bile su kudikamo veće od njihovih minimuma. Međutim, gotovi proizvod imao je karakterističan slankast, zatim blago pikantan te naposljetku gorkast okus, vjerojatno zbog interakcije različitih komponenata okusa

A Hierarchical Component-based WebGIS and Its Key Technologies

A practical hierarchical component-based WebGIS model referred to as Geo-Union is presented. Geo-Union consists of four layers: storage layer, service layer, component layer and application layer. Service layer is partitioned into another two layers: Geo-Union client and Geo-Union server. The architectures and object diagram of each layer in Geo-Union are discussed in details. After that, four key technologies adopted in Geo-Union (spatial data model, ORDB, spatial index and spatial cache) are summarized and analyzed, especially the spatial cache framework of Geo-Union. At last, some future works in WebGIS, such as interoperability, security, distributed computing and intelligent computing, are indicated and simply explored

Black Start Capability from Large Industrial Consumers

The way of control and operation of an electrical power system has been changing rapidly with the integration of renewable energy sources (RES). One of the emerging issues that require addressing is the capability of RES to participate in the restoration process upon a total or partial system failure. However, with the continuous shutdown of large-centralised generators, which traditionally provided the black start support together with the variability of RES, the restoration process becomes much more complex. Primarily, the RES should have enough capacity to energise the load at the time of the restoration. Nonetheless, due to significant advantages, there is an increasing trend to use RES to meet the local energy demand by large industrial customers. The flexibility of shifting loads together with the surplus of RE generation could support the system operator during the system energisation process after a blackout. This paper mainly focuses on identifying the capabilities and factors that should be accounted for to participate in the system restoration process by large industrial consumers. The case study conducted on a large-scale steel factory in the UK reveals the possibility of supporting the restoration process under the bottom-up approac

Fast generation of mock galaxy catalogues with COLA

We investigate the feasibility of using COmoving Lagrangian Acceleration (COLA) technique to efficiently generate galaxy mock catalogues that can accurately reproduce the statistical properties of observed galaxies. Our proposed scheme combines the subhalo abundance matching (SHAM) procedure with COLA simulations, utilizing only three free parameters: the scatter magnitude ($\sigma_{\rm scat}$) in SHAM, the initial redshift ($z_{\rm init}$) of the COLA simulation, and the time stride ($da$) used by COLA. In this proof-of-concept study, we focus on a subset of BOSS CMASS NGC galaxies within the redshift range $z\in [0.45, 0.55]$. We perform $\mathtt{GADGET}$ simulation and low-resolution COLA simulations with various combinations of $(z_{\rm init}, da)$, each using $1024^{3}$ particles in an $800~h^{-1}{\rm Mpc}$ box. By minimizing the difference between COLA mock and CMASS NGC galaxies for the monopole of the two-point correlation function (2PCF), we obtain the optimal $\sigma_{\rm scat}$. We have found that by setting $z_{\rm init}=29$ and $da=1/30$, we achieve a good agreement between COLA mock and CMASS NGC galaxies within the range of 4 to $20~h^{-1}{\rm Mpc}$, with a computational cost two orders of magnitude lower than that of the N-body code. Moreover, a detailed verification is performed by comparing various statistical properties, such as anisotropic 2PCF, three-point clustering, and power spectrum multipoles, which shows similar performance between GADGET mock and COLA mock catalogues with the CMASS NGC galaxies. Furthermore, we assess the robustness of the COLA mock catalogues across different cosmological models, demonstrating consistent results in the resulting 2PCFs. Our findings suggest that COLA simulations are a promising tool for efficiently generating mock catalogues for emulators and machine learning analyses in exploring the large-scale structure of the Universe.Comment: 24 pages, 14 figures, 4 table