• Journal of information and communication convergence engineering
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• 제16권2호
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• pp.84-92
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• 2018

For large wireless sensor networks running on battery power, the time synchronization of all sensor nodes is becoming a crucial task for waking up sensor nodes with exact timing and controlling transmission and reception timing. However, as network size increases, this synchronization process tends to require long processing time consume significant power. Furthermore, a naïve synchronization scheduler may leave some nodes unsynchronized. This paper proposes a power-efficient scheduling algorithm for time synchronization utilizing the notion of density, which is defined by the number of neighboring nodes within wireless range. The proposed scheduling algorithm elects a sequence of minimal reference nodes that can complete the synchronization with the smallest possible number of hops and lowest possible power consumption. Additionally, it ensures coverage of all sensor nodes utilizing a two-pass synchronization scheduling process. We implemented the proposed synchronization algorithm in a network simulator. Extensive simulation results demonstrate that the proposed algorithm can reduce the power consumption required for the periodic synchronization process by up to 40% for large sensor networks compared to a simplistic multi-hop synchronization method.

• 대한임상검사과학회지
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• 제43권1호
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• pp.6-11
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• 2011

In clinical chemistry tests, the interfering substances such as hemoglobin, lipid, bilirubin, and drugs, etc. can cause the changes of test results performed by spectrophotometrical methods. We evaluated the effects of interfering substances on the test results by adding interfering substances on the samples in the 19 kinds of clinical chemistry tests such as aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase, gamma-glutamyltransferase, total protein, albumin, glucose, total cholesterol, total bilirubin, triglyceride, uric acid, calcium, inorganic phosphours, high density lipoprotein cholesterol, low density lipoprotein cholesterol, creatinine, blood urea nitrogen, and C-reactive protein using newly implemented automatic chemical analyzer Toshiba TBA-C8000 under the direction of CLSI EP07-A guideline. Hemolytic samples show increased concentration of total protein, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase and reduced concentration of total bilirubin, alkaline phosphatase by interfering effect. Hyperlipemic samples show increased concentration of total protein and alkaline phosphatase and reduced concentration of low density lipoprotein cholesterol. The samples with conjugated bilirubinemia show increased concentration of inorganic phosphours, otherwise the samples with unconjugated bilirubinemia show no interference or allowable range in the test result.

• 천문학회보
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• 제43권2호
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• pp.33.1-33.1
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• 2018

Ram pressure stripping by intracluster medium (ICM) can play a crucial role in galaxy evolution in the high-density environment as seen by many examples of cluster galaxies. Although much progress has been made by direct numerical simulations of galaxies (or a galaxy) as a whole in a cluster environment, the interstellar medium (ISM) in galactic disks is not well resolved to understand responses of the ISM in details. In order to overcome this, we utilize the TIGRESS simulation suite that focuses on a local region of galactic disks and resolves key physical processes in the ISM with uniformly high resolution. In this talk, we present the results from the solar neighborhood TIGRESS model facing the ICM winds with a range of ram pressures. When ram pressure is weaker than and comparable to the ISM weight, the ICM winds simply reshape the ISM to the one-sided disk, but star formation rates remain unchanged. Although there exist low-density channels in the multiphase ISM that allow the ICM winds to penetrate through, the ISM turbulence quickly closes the channels and prevents efficient stripping. When ram pressure is stronger than the ISM weight, a significant amount of the ISM can be stripped away rapidly, and star formation is quickly quenched. While the low-density gas is stripped rapidly, star formation still occurs in the extraplanar dense ISM (1-2kpc away from the stellar disk). Finally, we quantify the momentum transfer from the ICM to the ISM using the mass-and momentum-weighted velocity distribution functions of each gas phase.

• Journal of Microbiology and Biotechnology
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• 제6권3호
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• pp.221-224
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• 1996

Pseudomonas putida BM01 was grown efficiently on glucose as the sole carbon source with a supply of a nitrogen source in pH-stat mode using a low setpoint limit. A final cell concentration of 100 g/l was obtained in 30 h of fed-batch cultivation by controlling glucose concentration within the range of 5-20 g/l and maintaining dissolved oxygen tension above 10$%$ saturation using pure oxygen. This high cell density culture technique is believed highly useful for the production of poly(3-hydroxyalkanoates) by this strain.

• 한국표면공학회지
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• 제28권6호
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• pp.352-360
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• 1995

The effect of electrolysis conditions on the composition, the magnetic properties and the preferred orientation of Ni-Fe-Co alloy deposits was investigated using the sulfate-chloride bath paddle agitated. Cathode current efficiency increases with the current density, showing the different tendency of the variation from that of the Ni-Fe electrodeposits. The Co content of the deposits decreases with increasing current density, while the content of Ni and Fe is shown to be minimum or maximum at 3A/$dm^2$ respectively. The Ni/Fe ratio of the alloy deposits is lower than that of Ni-Fe deposits. The coercive force($H_c$) of the deposits increases with the Co content in deposit, showing the relatively low value in the range of 1.8~5.0Wt.% Co. The anisotropy field ($H_k$) of the deposits is higher than that of Ni-Fe alloy deposits, The preferred orientation of the deposits is generally (200), but the orientation factor(R) changes with both the increase of current density and the magnetic field applied during deposition.

• Journal of the Korean Wood Science and Technology
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• 제48권4호
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• pp.450-457
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• 2020

Single pellet press technology allows for fast, low-cost, and small-scale tests to investigate pelletizing characteristics. We estimated proper compression ratios for five Korean domestic wood species through predicted relationships between pelletizing pressure P_x and compression ratio based on experimental data obtained from a single pellet press unit. The pressures required to obtain a 6-mm-diam pellet of density 1200 kg/㎥ were estimated as 111 MPa for Populus davidiana, 133 MPa for Robinia pseudoacacia, 136 MPa for Quercus mongolica, 97 MPa for Pinus densiflora, and 127 MPa for Pinus rigida. On the basis of these pressures, we estimated proper compression ratios to be within the range 7.676-8.410 for these species, and we found the compression ratios needed for hardwood species to be somewhat higher than those needed for softwood species to obtain the pellet density of 1200 kg/㎥.

• 대한기계학회논문집A
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• 제30권10호
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• pp.1242-1248
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• 2006

Densification behavior of nanocrystalline titania powder was investigated under cold compaction. Experimental data were obtained under triaxial compression with various loading conditions. Lee and Kim proposed the Cap model by developing the parameters involved in the yield function of general Cap model and volumetric strain evolution under cold isostatic pressing. The parameters in the Drucker/Prager Cap model and the proposed model were obtained from experimental data under triaxial compression. Finite element results from the models were compared with experimental data for densification behavior of nanocystalline ceramic powder under cold isostatic pressing and die compaction. The proposed model agreed well with experimental data under cold compaction, but the Drucker/Prager Cap model underestimated at the low density range. Finite element results, also, show the relative density distribution of nanocystalline ceramic powder compacts is severe compared to conventional micron powder compacts with the same averaged relative density.

• Journal of the Korean Wood Science and Technology
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• 제32권6호
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• pp.50-56
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• 2004

This study was conducted to investigate the performance of sound absorption type-noise barriers manufactured with a combination of wood particles used for particleboard, recycled waste newspaper, and cement. An average density of wood-combined cement board was in the range from 0.83 to 0.96 g/cm³, showing relatively low-density board. Regardless of types of cement bonded board or wooden board, the board with concave holes(凹)-formed surfaces showed greater sound absorption coefficient compared to those of flat surface boards. The board density was not related with those coefficients. Accordingly, it was concluded that concave or deep corrugated surface structure has played an important role in sound absorption for the application of sound absorption type-noise barrier.

• 성인간호학회지
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• 제27권1호
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• pp.94-105
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• 2015

Purpose: This study was aimed to investigate the effects of the nutritional intervention program including DASH diet education and calcium/vitamin D supplements in Korean elderly women. Methods: This was a quasi-experimental study employing non-equivalent control group pretest-posttest design. The experimental group (n=26) was given DASH diet education and supplements (calcium 1200mg and vitamin 800 IU) while the control group (n=16) was given only general health consults. After the interventions, differences were analyzed in nutrient intake, bone turnover markers and bone mineral density between the two groups. Results: After one year, bone mineral density was found reduced in both groups, but showed higher levels (p=.003) in the experimental group than the control group. After research, nutrient intakes of participants improved generally, yet there was no significant difference between the two groups. The experimental group was divided into subgroups after interventions according to the level of calcium intake, and bone density and bone markers were compared between the subgroups. In a subgroup whose calcium intake was in the normal range, bone mineral density was significantly high (p=.002) while CTx and osteocalcin were significantly low (p=.003, p=.006, respectively). Conclusion: This study is significant in that it provided a nutritional intervention program for one year to elderly women who are susceptible to osteoporosis and severely low in dietary calcium intake and it proved to be effective.

• Journal of Advanced Marine Engineering and Technology
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• 제30권1호
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• pp.157-168
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• 2006

Recently, interest in using Al alloys in ship construction instead of fiber-reinforced plastic (FRP) has increased because of the advantages of A) alloy ships over FRP ships, including high speed, increased load capacity. and ease of recycling. This paper investigated the mechanical and electrochemical properties of Al alloys in a slow strain rate test under various potential conditions. These results will provide reference data for ship design by determining the optimum protection potential regarding hydrogen embrittlement and stress corrosion cracking. In general, Al and Al alloys do not corrode on formation of a film that has resistance to corrosion in neutral solutions. In seawater, however, $Cl^-$ ions lead to the formation and destruction of a Passive film. In a potentiostatic experiment. the current density after 1200 sec in the Potential range of $-0.68\~-1.5\;V$ was low. This low current density indicates the protection potential range. Elongation at an applied potential of 0 V was high in this SSRT. However, corrosion protection under these conditions is impossible because the mechanical properties are worse owing to decreased strength resulting from the active dissolution reaction in parallel parts of the specimen. A film composed of $CaCO_3\;and\;Mg(OH)_2$ confers corrosion resistance. However, at potentials below -1.6 V forms non-uniform electrodeposition coating, since there is too little time to form a coating. Therefore, we concluded that the mechanical properties are poor because the effect of hydrogen gas generation exceeds that of electrodeposition. Comparison of the maximum tensile strength, elongation, and time to fracture indicated that the optimum protection potential range was from -1.45 to -0.9 V (SSCE).