Subassemblage test of buckling‐restrained braces with H‐shaped steel core

In this study, a subassemblage test was performed using buckling‐restrained braces with an H‐shaped core element, which have been proven in a previous uniaxial component test to have good performance. The loading protocol prescribed the quasi‐static cyclic pattern with stepwise incremental displacement amplitude. Two different end connections (bolted connection and pin connection) and two different buckling‐restrained mechanisms (concrete‐filled tube and hollow steel tube) were examined as the test parameters. The performance of the specimen was evaluated by comparing the test results with the recommended provisions for buckling‐restrained braces. The test results showed that the compression strength capacity of buckling‐restrained brace (BRB) with in‐filled concrete increased by about 10% compared with BRB without in‐filled concrete. According to test result at same story drift of 2D_bm, structural performance of pin connection specimen without bolt slippage is superior to bolted connection specimen. Also, bolted connection specimens showed similar performance for total energy dissipation and cumulative plastic ductility, regardless of the connection types and the existence of concrete filling. Copyright © 2014 John Wiley & Sons, Ltd.     

Meteorological effects on the levels of fecal indicator bacteria in an urban stream: A modeling approach

Gwangju Creek (GJC) in Korea, which drains a highly urbanized watershed, has suffered from substantial fecal contamination, thereby limiting the beneficial use of the water in addition to threatening public health. In this study, to quantitatively estimate the sinks and sources of fecal indicator bacteria (FIB) in GJC under varying meteorological conditions, two FIB (i.e., Escherichia coli and enterococci bacteria) were monitored hourly for 24 h periods during both wet and dry weather conditions at four sites along GJC, and the collected data was subsequently used to develop a spatiotemporal FIB prediction model. The monitoring data revealed that storm washoff and irradiational die-off by sunlight are the two key processes controlling FIB populations in wet and dry weather, respectively. FIB populations significantly increased during precipitation, with greater concentrations occurring at higher rainfall intensity. During dry weather, FIB populations decreased in the presence of sunlight in daytime but quickly recovered at nighttime due to continuous point-source inputs. In this way, the contributions of the key processes (i.e., irradiational die-off by sunlight, settling, storm washoff, and resuspension) to the FIB levels in GJC under different meteorological conditions were quantitatively estimated using the developed model. The modeling results showed that the die-off by sunlight is the major sink of FIB during the daytime in dry weather with a minor contribution from the settling process. During wet weather, storm washoff and resuspension are equally important processes that are responsible for the substantial increase of FIB populations.     

Security analysis of pure DDP-based cipher proper for multimedia and ubiquitous device

DDP-64, based on various controlled operations, is a 64-bit Feistel-like block cipher consisting of 10 rounds with a 128-bit key. It was designed to attempt to have a high security level and a high speed performance in hardware on ubiquitous computing systems and multimedia. In this paper, however, we show that DDP-64 doesn’t have a high security level, more precisely, we show that it is vulnerable to related-key differential attack. This attack, which is much faster than the key exhaustive search, requires about 2⁵⁴ data and 2⁵⁴ time complexities. This work is the first known cryptanalytic result on DDP-64 so far.     

Flush Optimizations to Guarantee Less Transient Traffic in Ethernet Ring Protection

Ethernet ring protection (ERP) technology, which is defined in ITU‐T Recommendation G.8032, has been developed to provide carrier grade recovery for Ethernet ring networks. However, the filtering database (FDB) flush method adopted in the current ERP standard has the drawback of introducing a large amount of transient traffic overshoot caused by flooded Ethernet frames right after protection switching. This traffic overshooting is especially critical when a ring provides services to a large number of clients. According to our experimental results, the traditional FDB flush requires a link capacity about sixteen times greater than the steady state traffic bandwidth. This paper introduces four flush optimization schemes to resolve this issue and investigates how the proposed schemes deal with the transient traffic overshoot on a multi‐ring network under failure conditions. With a network simulator, we evaluate the performance of the proposed schemes and compare them to the conventional FDB flush scheme. Among the proposed methods, the extended FDB advertisement method shows the fastest and most stable protection switching performance.     

Novel Shorted Meander‐Line USB Dongle Antenna with a Compact Ground Plane

This letter presents the design of a novel multiband USB dongle antenna with a compact ground plane. The radiating patch is composed of a modified meander‐line monopole and a shorted loop to generate a dual‐broadband resonance. The proposed antenna supports WiBro, Bluetooth, WLAN, WiMAX, and S‐DMB services. The total dimensions of the fabricated antenna are 10 mm × 45 mm × 1 mm, the most compact size among multiband USB dongle antennas reported to date. The measured 10 dB reflection loss bandwidths are 20.8% (2.24 GHz to 2.76 GHz) and 20.2% (4.86 GHz to 5.95 GHz). The measured peak gain is 2.97 dBi, and efficiency is higher than 58%. In addition, the radiation pattern approximates an omnidirectional pattern.     

Fast Super‐Resolution Algorithm Based on Dictionary Size Reduction Using k‐Means Clustering

This paper proposes a computationally efficient learning‐based super‐resolution algorithm using k‐means clustering. Conventional learning‐based super‐resolution requires a huge dictionary for reliable performance, which brings about a tremendous memory cost as well as a burdensome matching computation. In order to overcome this problem, the proposed algorithm significantly reduces the size of the trained dictionary by properly clustering similar patches at the learning phase. Experimental results show that the proposed algorithm provides superior visual quality to the conventional algorithms, while needing much less computational complexity.     

A tree-based slot allocation algorithm for loss-free slotted OBS networks

Optical burst switching (OBS) is regarded as one of the most promising switching technologies for next generation optical networks. However, the data burst contention problem is still unresolved thoroughly even though slotted OBS (SOBS) is studied as a new paradigm reducing the blocking rate. In this article, we propose a tree-based slot allocation (TSA) algorithm for loss-free SOBS networks, where the TSA algorithm originally avoids contention of the time-slots by reserving the time-slots with different time-slot positions for the source nodes, respectively. In order to manage the time-slots efficiently, we also propose an OBS superframe, which is a cyclic period and consists of multiple time-slots transmitted by the source nodes toward the same incoming port of a destination node. In addition, we attempt to optimize multiplexing of the OBS superframes to reduce wavelength consumption. On the other hand, when incoming traffic is beyond expectation, a source node may need more time-slots to prevent packet loss because of buffer overflow. For reallocation of the time-slots, we propose a flow control scheme managing some number of shared time-slots, where a control node adaptively allocates (or redeems) the time-slots to (or from) source nodes by utilizing the shared time-slots based on fluctuating traffic condition. Simulation results show that the blocking rate of the proposed TSA–OBS scheme is zero with acceptable queueing delay at moderate traffic offered loads. In addition, multiplexing optimization simulated in the 14-node NSFNET achieves a 63% reduction of wavelength consumption. Moreover, the proposed flow control scheme assisting the TSA algorithm maintains a target upper-bound of queueing delay at the source node, so that packet loss caused by buffer overflow is prevented.     

A new ionic liquids‐based monolithic column for determination of caffeine and theophylline

The present study has concentrated on finding a new stationary phase in liquid chromatography. To improve the selectivity of monolithic column, a new ionic liquids–based (ILs‐based) monolithic column (150 × 4.6 mm i.d.) is synthesized. Characteristic and evaluation of monolithic column are investigated by field emission‐scanning electron microscopy (FE‐SEM) and determination of caffeine and theophylline in high performance liquid chromatography (HPLC). FE‐SEM images show that this monolithic column has a porosity structure. At the condition of mobile phase was 0.06 mol L^?1 Na₂HPO₄ (pH 9.0) and flow rate was 0.7 mL min^?1, a good linear relationship was demonstrated when the concentrations of caffeine and theophylline were in the range of 0.1–60.0 μg mL^?1. These two compounds can obtain better resolution on the ILs‐based monolithic column than non‐ILs monolithic column, and the recoveries ranged from 97.40% to 108.00% and the interday and intraday relative standard deviations were less than 5%. The HPLC method, developed in this study, was proved to be acceptable for drugs assay, and this ILs‐based monolithic column as the stationary phase was a potential tool for future HPLC separation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Improvement of cephalosporin C production by Acremonium chrysogenum M35 in submerged culture with glass beads or silicone rubber

Physical stimulation using a baffle or an impeller has been previously reported to improve cephalosporin C (CPC) production and cell growth. In this study, the effect of glass beads on CPC production in Acremonium chrysogenum M35 was investigated in baffled flasks along with the morphological properties of the culture. Addition of glass beads into the culture broth was found to significantly influence CPC production and cell growth of A. chrysogenum M35 in baffled shake flasks. CPC concentration increased about 30% when compared with baffled flasks without glass beads. Morphological changes such as the total perimeter and number of units, total number of differentiated hyphae or arthrospores, corresponded to varied CPC concentrations. Specifically, total perimeter and number of units increased by more than 10%. However, changes in pH had no relationship to CPC production or the number of glass beads. Pieces of silicone rubber were mixed into a 5 L bioreactor culture to assess any improvement of CPC production. Once added into the main culture, the production of CPC increased about 30% while values of dissolved oxygen (DO), which can be used to estimate oxygen transfer rate (OTR), were lower than main medium without silicone rubber. And dry cell weight was also increased about 10% when silicone rubber was added into a 5 L bioreactor. Key words: Acremonium chrysogenum M35, Cephalosporin C, Glass Bead, Silicone Rubber, Oxygen Transfer Rate     

Cholesterol Removal from Squid Liver Oil by Crosslinked β-Cyclodextrin

The present study was designed to optimize the different conditions for β-cyclodextrin (β-CD) crosslinked by adipic acid on cholesterol removal from squid liver oil. Different factors were concentrations of crosslinked β-CD, mixing temperature, ratio of squid liver oil to distilled water, mixing time and mixing speed. It was found that cholesterol removal from squid liver oil was significantly affected by concentrations of crosslinked β-CD, mixing temperature, ratio of squid liver oil to distilled water, mixing time and mixing speed. In a recycling study, cholesterol removal from the squid liver oil with recycled crosslinked β-CD in the first recycling trial was 81.05%, which was slightly lower than that with new crosslinked β-CD (87.06%). In up to three time trials, over 70% of cholesterol removal was observed. The present study indicated that the optimum conditions for cholesterol removal from squid liver oil using crosslinked β-CD were a 1:3 ratio of squid liver oil to distilled water, 25% (crosslinked β-CD/distilled water, w/v) crosslinked β-CD concentration, 20 min mixing time, 800 rpm mixing speed and 55 °C mixing temperature with about 87% cholesterol removal.