• Journal of Information Processing Systems
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• v.4 no.4
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• pp.133-144
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• 2008

Clusters have become a popular alternative for building high-performance parallel computing systems. Today's high-performance system area network (SAN) protocols such as VIA and IBA significantly reduce user-to-user communication latency by implementing protocol stacks outside of operating system kernel. However, emerging parallel applications require a significant improvement in communication latency. Since the time required for transferring data between host memory and network interface (NI) make up a large portion of overall communication latency, the reduction of data transfer time is crucial for achieving low-latency communication. In this paper, Eager Data Transfer (EDT) mechanism is proposed to reduce the time for data transfers between the host and network interface. The EDT employs cache coherence interface hardware to directly transfer data between the host and NI. An EDT-based network interface was modeled and simulated on the Linux-based, complete system simulation environment, Linux/SimOS. Our simulation results show that the EDT approach significantly reduces the data transfer time compared to DMA-based approaches. The EDTbased NI attains 17% to 38% reduction in user-to-user message time compared to the cache-coherent DMA-based NIs for a range of message sizes (64 bytes${\sim}$4 Kbytes) in a SAN environment.

• Journal of Radiation Industry
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• v.5 no.2
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• pp.151-157
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• 2011

Crosslinked SPEEK/PVDF membrane were prepared by EB radiation method with various contents of PVDF. The prepared membranes were subjected to a comparative study of proton exchange membranes for fuel cell appreciations. The crosslinked SPEEK/PVDF membranes were characterized by using DMA, DSC and SAXS. The DMA data indicate that the ionic modulus values and cluster $T_g$ decrease with increasing PVDF content. Thus, it was suggested that the number of clustering in the crosslinked membranes can be reduced with increasing PVDF content. The DSC results were shown that the degree of crystalline of the membrane increased with increasing PVDF content. The morphology of the crosslinkied membranes was shown that with increasing PVDF content, the number of crystalline domain of the SPEEK/PVDF membranes increased but ionic aggregation of the membranes decreased. The water uptake behavior, ionic exchange capacity (IEC) and proton conductivity were decreased with increasing PVDF content. The overall findings suggest that the crosslinked membranes offer the possibility for improving the performance of PEMFC, provided that the membranes have thermal and hydration stability.

• Smart Structures and Systems
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• v.15 no.1
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• pp.191-207
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• 2015

Proper placement of sensors plays a key role in construction and implementation of an effective structural health monitoring (SHM) system. This paper proposes a novel methodology called the distributed monkey algorithm (DMA) for the optimum design of SHM system sensor arrays. Different from the existing algorithms, the dual-structure coding method is adopted for the representation of design variables and the single large population is partitioned into subsets and each subpopulation searches the space in different directions separately, leading to quicker convergence and higher searching capability. After the personal areas of all subpopulations have been finished, the initial optimal solutions in every subpopulation are extracted and reordered into a new subpopulation, and the harmony search algorithm (HSA) is incorporated to find the final optimal solution. A computational case of a high-rise building has been implemented to demonstrate the effectiveness of the proposed method. Investigations have clearly suggested that the proposed DMA is simple in concept, few in parameters, easy in implementation, and could generate sensor configurations superior to other conventional algorithms both in terms of generating optimal solutions as well as faster convergence.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.4
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• pp.299-309
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• 2019

Waterworks facilities inevitably experience some amount of leakage even if there is a lot of investment or state-of-the-art technology that is applied such as DMA(District Metered Area) system construction, leakage detection, repair, pipe rehabilitation, etc. The primary reason is the leakage is naturally restored over time. In the UK, this restoration characteristic is defined as NRR(Natural rate of rise of leakage) and used to decision making for prioritizing active leakage control of DMAs. However, this restoration characteristic is well recognized, but researches on NRR in the water distribution system are insufficient in Korea. In this study, the estimation method of NRR was developed suitable for applicating in Korea considering of SCADA data, water infrastructure, and water usage patterns by modification of the UK's NRR method. The proposed method was applied to 9 DMAs and verified it's applicability by comparing with the other water loss performance indicators. It is expected that the proposed method can be used to support decision making for sustainable NRW(Nor-revenue water) management in the water distribution system.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.169-169
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• 2023

Most distributed water is not used effectively due to water loss occurring in pipe networks. These water losses are caused by leakage, typically due to high water pressure to ensure adequate water supply. High water pressure can cause the pipe to burst or develop leaks over time, particularly in an aging network. In order to reduce the amount of leakage and ensure proper water distribution, it is important to apply pressure management. Pressure management aims to maintain a steady and uniform pressure level throughout the network, which can be achieved through various operational schemes. The schemes include: (1) installing a variable speed pump (VSP), (2) introducing district metered area (DMA), and (3) operating pressure-reducing valves (PRV). Applying these approaches requires consideration of various hydraulic, economic, and environmental aspects. Due to the different functions of these approaches and related components, an all-together optimization of these schemes is a complicated task. In order to reduce the optimization complexity, this study recommends a sequential optimization method. With three network operation schemes considered (i.e., VSP, DMA, and PRV), the method explores all the possible combinations of pressure management paths. Through sequential optimization, the best pressure management path can be determined using a multiple-criteria decision analysis (MCDA) to weigh in factors of cost savings, investment, pressure uniformity, and CO₂ emissions. Additionally, the contribution of each scheme to pressure management was also described in the application results.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.3
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• pp.291-306
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• 1984

The possibility of formation of carcinogenic N-nitrosamines such as nitrosodimethylamine(NDMA), nitrosodiethylamine (NDEA) and nitrosopyrolidine (NPYR) during the fermentation of Kimchi was investigated. Three different types of Kimchi, formulated with chinese cabbage, red pepper powder and garlic, with or without one of both fermented shrimp and anchovy juice, were cured for 75 days at $5^{\circ}C$. The changes in contents of nitrates, nitrites, pH, ascorbic acid, secondary amines, trimethyl-aminoxide (TMAO), trimethylamine (TMA) and NDMA were analyzed periodically during the fermentation. TMAO, TMA. DMA, nitrate, nitrite and ascorbic acid were analyzed by colorimetric methods, and NDMA, NPYR and NDEA were determined by the method of GLC-TEA. Although the total secondary amines markedly increased, no significant changes in the levels of TMAO and TMA were observed during the fermentation Kimchi added with fermented shrimp or anchovy juice. The predominating component of secondary amines was confirmed to be dimethylamine by means of nitrosating technique coupled with gas chromatography. No appreciable increase in the level of nitrites was appeared although nitrate level in the Kimchi apparently decreased. Non detectable or trace level of nitrosamine formation was detected whereas the nitrates fairly decreased during the fermentation of Kimchi. This could be explained by the fact that the lack of nitrites was resulted in the system due to rapid consumption of nitrites formed from nitrates by the reactions with ascorbic acid and amino acids which have been known as inhibitors of nitrosation reaction.

• Journal of Environmental Health Sciences
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• v.42 no.6
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• pp.450-464
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• 2016

Objectives: This study developed and validated reference materials (RMs) to analyze metal compounds in blood. Methods: We referred to KoNEHS (Korea National Environmental Health Survey) to estimate concentrations of blood metals (cadmium, Cd; lead, Pb; mercury, Hg) and applied analytical methods (inductively coupled plasma - mass spectroscopy, ICP-MS, for Cd and Pb; graphite furnace - atomic absorption spectrometry, GF-AAS, for Cd and Pb; and direct mercury analyzer, DMA, for Hg). Homogeneity and stability tests were carried out. In addition, certified values and uncertainties of RMs were calculated through internal and external experiments. All RMs were developed and assessed in various forms according to element, analytical method, and two types of concentration levels high concentration for occupational exposure and low concentration for environmental exposure. Results: All samples showed acceptable homogeneity, except for low concentration of Cd in the GF-AAS method. Short- and long-term stabilities were satisfied by ANOVA testing. In the inter-laboratory comparison, robust medians were lower than the certified values of all RMs (robust median/reference value; $1.301/1.327{\mu}g/L$ for Cd, ICP-MS, low concentration; $3.152/3.388{\mu}g/L$ for Cd, ICP-MS, high concentration; $1.219/1.301{\mu}g/L$ for Cd, GF-AAS, low concentration; $3.074/3.321{\mu}g/L$ for Cd, GF-AAS, high concentration; $14.473/14.516{\mu}g/L$ for Pb, ICP-MS, low concentration; $50.069/50.114{\mu}g/L$ for Pb, ICP-MS, high concentration; $12.881/14.147{\mu}g/L$ for Pb, GF-AAS, low concentration; $47.015/47.591{\mu}g/L$ for Pb, GF-AAS, high concentration; $4.059/4.218{\mu}g/L$ for Hg, DMA, low concentration; $11.474/11.181{\mu}g/L$ for Hg, DMA, high concentration). Conclusion: This study demonstrates procedures for developing and validating RMs for biomonitoring in the field of the environmental health.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.1
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• pp.13-18
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• 1978

The present study was conducted to elucidate the pattern in changes of trimethylamine oxide and related compounds in the muscle of Alaska pollack during drying, especially referred to formaladehyde and dimethylamine. Three kinds of dried samples of Alaska pollack, sun dried, hot-air dried, and salted-sun dried, were prepared and analyzed for their contents of trimethylamine oxide, trimethylamine, dimethylamine, and formaldehyde. The amount of trimethylamine oxide remained in the salted-sun dried sample was relatively higher than those in the other two samples. In the content of trimethylamine, the hot-air dried sample showed an exceedingly high value shelving forty-two times higher than the raw sample while the other two samples showed barely three to four times content based on the raw sample. The dimethylamine content in the hot-air fried sample was comparatively lower than those in the other two samples, the former marked about ten folds of the raw sample's and tile latter showed about fifteen folds, respectively. Refering to the content of formaldehyde, it decreased to eighty-three percent of initial content in the hot-air dried sample. On the contrary, it increased about two times initial content in the other two samples, respectively. As a tendency, the formaldehyde content appeared increased or decreased correlatively with the dimethylamine content, whereas the case was reverse for the trimethylamine content.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.1
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• pp.7-14
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• 1981

Secondary amines are known as one of the precursors of nitrosamines which are potent carcinogenic compounds for human being and animals. In this study, trimethylamine and dimethylamine contents of salted, hot-air dried and sun dried samples of two commercial fishes, mackerel pike and seerfish were analyzed and quantitatively compared at three different temperature conditions. The formation of both secondary amines was more rapid at$10^{\circ}C\;and\;15^{\circ}C\;than\;at\;2^{\circ}C$. Residual amounts of trimethylamine oxide of salted samples were relatively higher than those of the other samples. Trimethylamine contents of hot-air dried mackerel pike and sun dried seerfish were relatively higher than those in the other samples, while those of salted samples were comparatively lower than those of others. Dimethylamine contents of hot-air dried samples were higher than those of the other samples, whereas those of salted samples were comparatively lower than those of the other samples.

• Elastomers and Composites
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• v.49 no.1
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• pp.24-30
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• 2014

3-Amino-1,2,4-triazole (ATA) (2.5 and 5.0 phr) was incorporated into a immiscible maleated ethylene propylene diene rubber(mEPDM)/maleated high density polyethylene(mHDPE) (50 wt%/50 wt%) blend by melt mixing. Effects of the ATA on structure, mechanical and rheological properties of the blend was investigated. FT-IR and DMA results revealed that supramolecular hydrogen bonding interactions between the polymer chains occur by reaction of ATA with maleic anhydride grafted onto the component polymers in the blend, which induces the physical crosslinks in the blend. FE-SEM analysis showed that mEPDM forms a dispersed phase in continuous mHDPE matrix, and the blend with the ATA has finer phase morphology as compared to the blend without the ATA. By the addition of ATA in the blend, there were significant increases in tensile strength, modulus and elongation-at-break as well as elastic recoverability. Melt rheology studies revealed that ATA induced substantial increase in storage modulus and complex viscosity of the blend at the melt state.