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81.
In a many-to-many communication setting like a virtual community, individuals may be strongly tempted to free-ride on others' contributions, which would eventually lead to the collapse of the community. To find a structural solution to the "communication dilemma," this study compared the performances of 2 communication structures—one based on the interpersonal networks (network-generalized exchange: NEX ; e.g., blogs) and the other based on a public electronic bulletin board (group-generalized exchange: GEX ). In a 2 × 2 × 2 longitudinal between-subject experiment, it was found that changing GEX to NEX could increase the contributions made by individuals. Furthermore, NEX was found to be an effective structure for N-person communication particularly when a large number of individuals were involved. The findings imply that an individual's cooperative motivation is a function of the incentive structure of a particular form of information exchange, which means that altering the exchange form may be a possible solution to the communication dilemmas in virtual communities. 相似文献
82.
Byung‐Ju Sohn Hye‐Sook Park Hyo‐Jin Han Myoung‐Hwan Ahn 《International journal of remote sensing》2013,34(10):3033-3042
The calibration of four MTSAT‐1R infrared channels was evaluated by comparing MTSAT measurements with Terra/MODIS inferred MTSAT‐equivalent brightness temperatures during August 2005 and August 2006. Theoretical relationships converting MODIS brightness temperatures to MTSAT‐equivalent values were obtained and used for the comparison. Results indicate that MTSAT two split window channels are well calibrated, and no serious systematic errors or biases are found; and the MTSAT water‐vapour channel shows a good linear relationship but with a warm bias up to 2 K. The significant cold bias of MTSAT 3.7 µm channel about ?6.7 K in August 2005 is found to be much removed in August 2006, after correction of the electrical crosstalk between MTSAT‐1R SWIR channel and WV channel starting from March 2006. Since then, calibration performances of MTSAT‐1R split window channels and shortwave IR channel seem to be comparable with MODIS calibration, while the water‐vapour channel shows more uncertainties up to 2 K of bias. 相似文献
83.
The implementation of TS MAC system for KOREASAT DBS (direct broadcast satellite) system is presented. This TS MAC controls and monitors the status of the TS equipment and gathers the alarm for them. The advantage of this system is the center-concentrated, real time processing, remote control, and object oriented module decomposing 相似文献
84.
Byong?Joo?KimEmail author Byung?Hu?Sohn Kee?Kahb?Koo 《Journal of Mechanical Science and Technology》2003,17(3):429-439
Counter-current two-phase flows of air-water in narrow rectangular channels with offset-strip fins have been experimentally
investigated in a 760 mm long and 100 mm wide test section with 3.0 and 5.0 mm gap widths. The two-phase flow regime, channel-average
void fractions and two-phase pressure gradients were studied. Flow regime transition occurred at lower superficial velocities
of air than in the channels without fins. In the bubbly and slug flow regimes, elongated bubbles rose along the subchannel
formed by fins without lateral movement. The critical void fraction for the bubbly-to-slug transition was about 0.14 for the
3 mm gap channel and 0.2 for the 5 mm gap channel, respectively. Channel-average void fractions in the channels with fins
were almost the same as those in the channels without fins. Void fractions increased as the gap width increased, especially
at high superficial velocity of air. The presence of fins enhanced the two-phase distribution parameter significantly in the
slug How, where the effect of gap width was almost negligible. Superficial velocity of air dominated the two-phase pressure
gradients. Liquid superficial velocity and channel gap width has only a minor effect on the pressure gradients. 相似文献
85.
Soo-In Sohn Jae-Hyung Ahn Subramani Pandian Young-Ju Oh Eun-Kyoung Shin Hyeon-Jung Kang Woo-Suk Cho Youn-Sung Cho Kong-Sik Shin 《International journal of molecular sciences》2021,22(11)
Bacterial communities in rhizosphere and root nodules have significant contributions to the growth and productivity of the soybean (Glycine max (L.) Merr.). In this report, we analyzed the physiological properties and dynamics of bacterial community structure in rhizosphere and root nodules at different growth stages using BioLog EcoPlate and high-throughput sequencing technology, respectively. The BioLog assay found that the metabolic capability of rhizosphere is in increasing trend in the growth of soybeans as compared to the bulk soil. As a result of the Illumina sequencing analysis, the microbial community structure of rhizosphere and root nodules was found to be influenced by the variety and growth stage of the soybean. At the phylum level, Actinobacteria were the most abundant in rhizosphere at all growth stages, followed by Alphaproteobacteria and Acidobacteria, and the phylum Bacteroidetes showed the greatest change. But, in the root nodules Alphaproteobacteria were dominant. The results of the OTU analysis exhibited the dominance of Bradyrhizobium during the entire stage of growth, but the ratio of non-rhizobial bacteria showed an increasing trend as the soybean growth progressed. These findings revealed that bacterial community in the rhizosphere and root nodules changed according to both the variety and growth stages of soybean in the field. 相似文献
86.
Kyung-Hyun Sohn & Hyong-Joo Lee 《International Journal of Food Science & Technology》1998,33(4):359-365
The effects of high pressure treatment on the microflora and storage of kimchi were investigated. In a bacterial suspension, numbers of Lactobacillus plantarum were reduced by 6 logs by 500 MPa, at 25 °C for 10 min. Kimchi juice did not alter the rate of inactivation of lactic acid bacteria by high pressure treatment. There was no change in the texture of kimchi subjected to a pressure of 400 MPa, but an increase in cutting force was observed at 600 MPa. When kimchi was pressurized at 400 MPa for 10 min at 25 °C and subsequently stored at 20 °C for 4 weeks, the total number of viable cells stayed at 103 CFU mL−1 . High pressure treatment above 400 MPa prevented excessive acidification that typically occurs during the extended storage of kimchi. The inflation of pouches as a result of accumulated carbon dioxide was also prevented by high pressure treatment. Although colour changes were accelerated by high pressure treatment, this study demonstrates that high pressure treatment can be used to control overripening during the distribution and storage of kimchi products. 相似文献
87.
B. Jayaraj S. Vishweswariah V. H. Desai Y. H. Sohn 《JOM Journal of the Minerals, Metals and Materials Society》2006,58(1):60-63
Thermal barrier coatings (TBCs) are improving the performance and efficiency of advanced gas turbine engines by allowing higher
inlet temperature and insulation of critical hot-section components. Monitoring the integrity of TBCs prior to failure is
critical to the overall performance of gas turbine en gines and requires a robust nondestructive evaluation (NDE) technique.
In this paper, changes in electrochemical impedance with microstructural degradation of critical constituents in TBCs are
summarized for the development of electrochemical impedance spectroscopy as an NDE technique for TBCs. 相似文献
88.
Kim Y Lee H Lee CR Park DU Yang JS Park IJ Lee KY Lee M Kim TK Sohn NS Cho YS Lee N Chung HK 《The Science of the total environment》2002,286(1-3):181-189
To evaluate lead exposure among secondary lead-smelting workers with a focus on erythrocyte pyrimidine 5'-nucleotidase (P5N) activity, blood lead concentration (PbB), activity of P5N and other biological variables were examined in 88 exposed workers in five secondary lead smelters and in 24 non-exposed workers in Korea. All of the mean values of air lead concentration (PbA) in the three processes, scrap pretreatment, blast furnace smelting, and refining and casting of the secondary lead smelters, markedly exceeded 0.05 mg/m3. In this survey, 29 (97%) of 30 air samples for lead exceeded 0.05 mg/m3. The highest mean PbA and PbB values were found in the section of blast furnace smelting. All of the mean PbB values in all the sections were higher than 30 microg/dl. PbB of 71 (81%) of the 88 exposed workers exceeded 30 microg/dl. In 31 (35%) of the exposed workers, PbB was above 60 microg/dl. Compared with the non-exposed group, zinc protoporphyrin (ZPP) in the exposed group was significantly increased, whereas erythrocyte P5N activity and activity of erythrocyte delta-aminolevulinic acid dehydratase (ALAD) were significantly inhibited. Erythrocyte P5N activity had valid biological correlation with PbB and with other biological variables, such as ALAD activity or ZPP. Lead exposure affected hemoglobin levels via inhibition of P5N activity, as well as the heme biosynthetic pathway, in the high-exposure state. 相似文献
89.
Simulated annealing is known to be an efficient method for combinatorial optimization problems. Its usage for realistic problem size, however, has been limited by the long execution time due to its sequential nature. This report presents a practical approach to synchronous simulated annealing for massively parallel distributed-memory multiprocessors. We use an n-ary speculative tree to execute n different iterations in parallel on n processors, called generalized speculative computation (GSC). Execution results of the 100- to 500-city traveling salesman problems on the AP1000 massively parallel multiprocessor demonstrate that the GSC approach can be an effective method for parallel simulated annealing as it gave over 20-fold speedup on 100 processors 相似文献
90.
Certain new sulfide-smelting processes and coal-gasification processes generate high-strength sulfur dioxide streams, for
which a new process for converting sulfur dioxide to elemental sulfur needs to be developed because no process exists that
is generally and economically applicable to the treatment of such streams. A thermodynamic and experimental investigation
to develop a new process for converting sulfur dioxide to elemental sulfur by a cyclic process involving calcium sulfide and
calcium sulfate without generating secondary pollutants was carried out. In this process, the starting raw material, calcium
sulfate, is reduced by a suitable reducing agent, such as hydrogen, to produce calcium sulfide, which is used to reduce sulfur
dioxide to elemental sulfur vapor and calcium sulfate. The latter is, in turn, reduced to regenerate calcium sulfide. In this
Part I, detailed experimental results are presented on the kinetics of the reaction between sulfur dioxide and calcium-sulfide
pellets, which produces elemental sulfur and calcium sulfate. The experiments were carried out at temperatures between 1023
and 1088 K and sulfur-dioxide partial pressures between 9 and 60 kPa by the use of a thermogravimetric analysis (TGA) technique.
The rate of this reaction was demonstrated by the conversion of 40 pct calcium-sulfide pellets obtained from the hydrogen
reduction of fresh calcium sulfate in 10 minutes at 1073 K under a sulfur-dioxide partial pressure of 43 kPa. The reactivity
decreased somewhat during the first three cycles but remained largely unchanged thereafter up to the tenth cycle. This characteristic
of the pellets is important because the solids must be reusable for repeated cycles to avoid generating secondary pollutants.
A pore-blocking model was found to fit the reaction rate. The reaction is first order with respect to sulfur-dioxide partial
pressure and has an activation energy of 101 to 134 kJ/mol (24 to 32 kcal/mol) for calcium-sulfide pellets reacted and regenerated
several different times. Sulfur dioxide-containing streams from certain sources, such as the regenerator off-gas from an integrated-gasification,
combined-cycle, desulfurization unit and new sulfide-smelting plants, contain much higher partial pressures of SO2. In these cases, the rate of the first reaction is expected to be proportionally higher than in the test conditions reported
in this article. The reduction kinetics of calcium-sulfate pellets with hydrogen gas is reported in the accompanying Part
II. 相似文献