• Journal of Korean Society of Forest Science
• /
• v.24 no.1
• /
• pp.25-44
• /
• 1974

In the present paper I described the results of the observations made on the visual characteristics such as the annual ring width and summerwood percentage of Pinus koraiensis Sieb. et Zucc. grown at out university forest. The results of the study are as follows: Characteristics of annual ring width and summerwood percentage 1. The range of dispersion of annual ring width and summerwood percentage are respectively 0.5-6.5mm and 5-50% on the normal wood and its arithmetic mean values are each 3.0mm and 24% on all sample trees. 2. The values of annual ring width of heart wood are larger than that of sapwood but on the contrary the values of summerwood percentage of heartwood are smaller than that of sapwood. On the other hand variations of these values are distingushed on the heartwood. 3. The values of annual ring width due to the parts of stem with crown. with clear length and at bottom showed that the largest values are given at the parts of stem with crown. But on the contrary the summerwood percentage values are largest at the parts of stem at bottom on all sample trees. 4. The values of annual ring width and summerwood percentage depending on the stand sides are not obvious. Horizontal and vertical variations of annual ring width and summerwood percentage 5. It was recognized that horizontal (radial direction) variations of annual ring width and summerwood percentage indicated two different patterns (the region of large fluctuation and that of small fluctuation) in a tree stem. These boundaries are seemed to appear at the parts of 12-15 annual rings from pith. 6. According to the increase of height in tree the values of annual ring width increase but the values of summerwood percentage gradually decrease. 7. But vertical variations of annual ring width and summerwood percentage on the sapwood are divided into two different parts (region of increased or decreased upwards and that of remained constant in successive height) in a tree stem and these limits are seemed to appear at the 7m of height in trees. Relations between annual ring width and summerwood percentage 8. The modes of summerwood percentage related with annual ring width are seemed to appear almost in the definite range (10-25%). 9. The relations between annual ring width and summerwood percentage show a highly negatine correlation on all sample trees.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.27 no.5
• /
• pp.482-494
• /
• 1994

Most of carotenoprotein complexes have been extracted by using buffered solutions. However, in this study carotenoprotein from the muscle of Blue mussel(Mytilus edulis) was extracted by a detergent such as Triton X-100. It was purified and characterized by $20\%$ (w/v) $(NH_4)_2SO_4$, DEAE-cellulose ion exchange and Sephacryl S-300 gel filtration. The carotenoprotein(${\lambda}_{max}=462nm$) had an approximate M. W. of 372KDa(gel filtration). SDS-PAGE analysis of the carotenoprotein indicated the presence of four polypeptides of 60KDa($23.70\%$), 46.9KDa($9.14\%$), 26KDa($49.14\%$) and 13KDa($18.02\%$). Carotenoprotein denaturated by treatment with SDS to a final concentration of $0.2\%$ (w/v) caused a hypsochromic shift of ${\lambda}_{max}$ from 462nm to 456nm. The carotenoprotein contained lipids as structure units. The amino acid composition of the carotenoprotein contained large essential amino acid amounts of $62.8\%$, and the content of threonine($35.9\%$) was higher than other amino acids, but histidine, methionine and proline were not present. In the carotenoprotein, the major fatty acids were $C_{16:4},\;C_{16:0},\;C_{20:5}\;and\;C_{22:6}$. The percentages of polyunsaturated fatty acids($62.4\%$) were higher compared to other fatty acids(saturated fatty acids $19.6\%$, monounsaturated fatty acids $18.0\%$). Carotenoid was extracted from the carotenoprotein by acetone and it was separated into five different components by preparative TLC(benzene:petroleum ether:acetone=69:17:14). The major components of carotenoid were mytiloxanthin($74.79\%$) and 3,4,3'- trihydroxy-7',8'-didehydro-${\beta}$-carotene($18.26\%$), and they were at least presented as prosthetic groups of carotenoprotein.

• Journal of Korea Port Economic Association
• /
• v.26 no.4
• /
• pp.188-206
• /
• 2010

Data Envelopment Analysis(DEA) is an operations research-based method for measuring the performance efficiency of decision units that are characterized by multiple inputs and outputs. DEA has been applied successfully as a performance evaluation tool in many fields. However, it has not been extensively applied in the shipbuilding industry. This paper applied the input-oriented DEA model, and Malmquist indices to the 7 shipbuilding firms to measure the efficiency and productivity changes during the period of 2004 to 2009. The Malmquist indices will be decomposed into three components such as pure efficiency change, scale efficiency change, and technical change. The empirical results show the following findings. First, the DEA findings indicate that main source of inefficiency is scale rather than pure technical. Second, the Malmquist indices show that an overall decrease in productivity.

• Asia Marketing Journal
• /
• v.12 no.4
• /
• pp.79-111
• /
• 2011

Digital economy has grown rapidly so that the new business area called 'Internet business' has been dramatically extended as time goes on. However, in the case of Internet business, market shares of individual companies seem to fluctuate very extremely. Thus marketing managers who operate the Internet sites have seriously observed the competition structure of the Internet business market and carefully analyzed the competitors' behavior in order to achieve their own business goals in the market. The newly created Internet business might differ from the offline ones in management styles, because it has totally different business circumstances when compared with the existing offline businesses. Thus, there should be a lot of researches for finding the solutions about what the features of Internet business are and how the management style of those Internet business companies should be changed. Most marketing literatures related to the Internet business have focused on individual business markets. Specifically, many researchers have studied the Internet portal sites and the Internet shopping mall sites, which are the most general forms of Internet business. On the other hand, this study focuses on the entire Internet business industry to understand the competitive circumstance of online market. This approach makes it possible not only to have a broader view to comprehend overall e-business industry, but also to understand the differences in competition structures among Internet business markets. We used time-series data of Internet connection rates by consumers as the basic data to figure out the competition patterns in the Internet business markets. Specifically, the data for this research was obtained from one of Internet ranking sites, 'Fian'. The Internet business ranking data is obtained based on web surfing record of some pre-selected sample group where the possibility of double-count for page-views is controlled by method of same IP check. The ranking site offers several data which are very useful for comparison and analysis of competitive sites. The Fian site divides the Internet business areas into 34 area and offers market shares of big 5 sites which are on high rank in each category daily. We collected the daily market share data about Internet sites on each area from April 22, 2008 to August 5, 2008, where some errors of data was found and 30 business area data were finally used for our research after the data purification. This study performed several empirical analyses in focusing on market shares of each site to understand the competition among sites in Internet business of Korea. We tried to perform more statistically precise analysis for looking into business fields with similar competitive structures by applying the cluster analysis to the data. The research results are as follows. First, the leading sites in each area were classified into three groups based on averages and standard deviations of daily market shares. The first group includes the sites with the lowest market shares, which give more increased convenience to consumers by offering the Internet sites as complimentary services for existing offline services. The second group includes sites with medium level of market shares, where the site users are limited to specific small group. The third group includes sites with the highest market shares, which usually require online registration in advance and have difficulty in switching to another site. Second, we analyzed the second place sites in each business area because it may help us understand the competitive power of the strongest competitor against the leading site. The second place sites in each business area were classified into four groups based on averages and standard deviations of daily market shares. The four groups are the sites showing consistent inferiority compared to the leading sites, the sites with relatively high volatility and medium level of shares, the sites with relatively low volatility and medium level of shares, the sites with relatively low volatility and high level of shares whose gaps are not big compared to the leading sites. Except 'web agency' area, these second place sites show relatively stable shares below 0.1 point of standard deviation. Third, we also classified the types of relative strength between leading sites and the second place sites by applying the cluster analysis to the gap values of market shares between two sites. They were also classified into four groups, the sites with the relatively lowest gaps even though the values of standard deviation are various, the sites with under the average level of gaps, the sites with over the average level of gaps, the sites with the relatively higher gaps and lower volatility. Then we also found that while the areas with relatively bigger gap values usually have smaller standard deviation values, the areas with very small differences between the first and the second sites have a wider range of standard deviation values. The practical and theoretical implications of this study are as follows. First, the result of this study might provide the current market participants with the useful information to understand the competitive circumstance of the market and build the effective new business strategy for the market success. Also it might be useful to help new potential companies find a new business area and set up successful competitive strategies. Second, it might help Internet marketing researchers take a macro view of the overall Internet market so that make possible to begin the new studies on overall Internet market beyond individual Internet market studies.

• Journal of Environmental Science International
• /
• v.3 no.3
• /
• pp.273-284
• /
• 1994

The primary objective of this study was to examine the toxic effects of PCP on activated sludge and to analyze its metabolic responses while treating wastewater containing pentachlorophenol (PCP) in a sequencing batch reactor (SBR) system operating under different control strategies. This study was conducted in two phases 1 and 2 (8-hr and 12-hr cycles). Each phase was operated with two control strategies I and II. Strategy I (reactor 1) involved rapid addition (5 minutes to complete) of substrate to the reactor with continuous mixing but no aeration for 2 hours. Strategy ll (reactor 2) involved adding the feed continuously during the first 2 hours of the cycle when the system was mixed but not aerated. During both phases each reactor was operated at a sludge age of 15 days. The synthetic wastewater was used as a feed. The COD of the feed solution was about 380 mg/l. After the reference response for both reactors was established, the steady state response of each system was established for PCP feed concentrations of 0.1 mg/l, 1.0 mg/l, and 5.0 mg/l in SBR systems operating on both 8-hr and 12-hr cycles. Soluble COD removal was not inhibited at any feed PCP concentrations used. At 5.0 mg/l fined PCP concentration and in SBR systems operating on phase 2, the concentrations of MLVSS were decreased; selective pressure on the mixed biomass might be increased, narrowing the range of possible ecological responses; the settleability of activated sludge was poor; the SOURS were increased, showing that the systems were shocked. Nitrification was made to some extent at all concentrations of feed PCP in SBR systems operating on phase 2 whereas in SBR systems operating on phase 1 little nitrification was observed. Then, nitrification will be delayed as much as soluble COD removal is retarded due to PCP inhibition effects. Enhanced biological phosphorus removal occurring in the system operating with control strategy I during phase 1 of this work and in the presence of low concentrations of PCP was unreliable and might cease at anytime, whereas enhanced biological phosphorus removal occurring in the system operating with either control strategy I or II during phase 2 of this work and in the Presence of feed PCP concentrations up to 1.0 mg/l was reliable. When, however, such processes were exposed to 5.0 mg/l PCP dose, enhanced phosphorus removal ceased and never returned.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.9
• /
• pp.717-722
• /
• 2001

This paper presents a methodology on the backward path tracking control of a trailer type robot which consists of two parts: a tractor and a trailer. It is difficult to control the motion of a trailer vehicle since its dynamics is non-holonomic. Therefore, in this paper, the modeling and parameter estimation of the system using a real-coded genetic algorithm(RCGA) is proposed and a backward path tracking control algorithm is then obtained based on the linearized model. Experimental results verify the effectiveness of the proposed method.

• Journal of Sericultural and Entomological Science
• /
• v.16 no.2
• /
• pp.35-53
• /
• 1974

A series of experiment was conducted to investigate the effects of the level of dietary Protein (soybean meal) and carbohydrate (sucrose) on the growth rate, feed efficiency, nutrients digestibility and amylase activity of larvae at 5th instar. The results obtained from the experimentation are summarized as follow： (1) It was found that the body weight gain, cocoon quality and feed efficiency of the 5th instar larvae were significantly affected by the level of protein and carbohydrate in the artificial diet. Present data revealed that the proper level of dietary protein and carbohydrate would be the most important factor for the optimum growth of larvae. (2) In the amount of diet consumption, the group of larvae gained more body weight consumed more diet than the group gained less amount of body weight. (3) Digestibility of nutrients was improved as the level of protein in the diet increased, although the level of dietary carbohydrate did not exert any positive results. (4) It was observed that the amylase activity in digestive juice was stimulated by the increasement of dietary carbohydrate. However, no correlation between the level of dietary protein and carbohydrate was detected in the amylase activity. (5) Analytical data indicated that the amount of protein or carbohydrate excreted through feces and urine was proportional to the content of protein or carbohydrate in artificial diet. The group o( larvae consumed the diet contained high protein excreted more protein and less nitrogen free extract than did the group received low protein diet. Likewise, the group of larvae fed high dietary carbohydrate excreted more nitrogen free extract and less protein through excreta than the group consumed low carbohydrate diet group. (6) Although the amylase activity of the larvae received the artificial diet was higher than the larvae received natural diet (mulberry leaf), the rate of body weight gam and the quality of cocoon produced from the natural diet group was better than the artificial diet group. It is, thus, concluded that feeding the larvae by the artificial diet may net be recommendable. (7) It was determined that the best level of protein (soybean meal) and carbohydrate (sucrose) in artificial diet was found to be 40g and 0g, respectively when it was fed to the 5th instar larvae. (8) It may be concluded from the results obtained that the artificial diet that could stimulate the activity of amylase nay not be recommendable for the practical larvae feeding Purpose due simply to the Poor economic return from this diet than natural diet.

• Journal of Aquaculture
• /
• v.6 no.4
• /
• pp.323-338
• /
• 1993

The primary objective of this study was to examine the toxic effects of PCP on activated sludge and to analyze its metabolic responses while treating wastewater containing pentachlorophenol (PCP) in a sequencing batch reactor (SBR) system operating under different control strategies. This study was conducted in two phases 1 and 2 (8-hr and 12-hr cycles). Each phase was operated with two control strategies I and II. Strategy I (reactor 1) involved rapid addition (5 minutes to complete) of substrate to the reactor with continuous mixing but no aeration for 2 hours. Strategy II (reactor 2) involved adding the feed continuously during the first 2 hours of the cycle when the system was mixed but not aerated. During both phases each reactor was operated at a sludge age of 15 days. The synthetic wastewater was used as a feed. The COD of the feed solution was about 380 mg/L. After the reference response for both reactors was established, the steady state response of each system was established for PCP feed concentrations of 0.1 mg/L, 1.0 mg/L, and 5.0 mg/L in SBR systems operating on both 8-hr and 12-hr cycles. Soluble COD removal was not inhibited at any feed PCP concentrations used. At 5.0 mg/L feed PCP concentration and in SBR systems operating on phase 2, the concentrations or ML VSS were decreased; selective pressure on the mixed biomass might be increased, narrowing the range of possible ecological responses; the settleability of activated sludge was poor; the SOURs were increased, showing that the systems were shocked. Nitrification was made to some extent at all concentrations of feed PCP in SBR systems operating on phase 2 whereas in SBR systems operating on phase 1 little nitrification was observed. Then, nitrification will be delayed as much as soluble COD removal is retarded due to PCP inhibition effects. Enhanced biological phosphorus removal occurring in the system operating with control strategy I during phase 1 of this work and in the presence of low concentrations of PCP was unreliable and might cease at anytime, whereas enhanced biological phosphorus removal occurring in the system operating with either control strategy I or II during phase 2 of this work and in the presence of feed PCP concentrations up to 1.0 mg/L was reliable. When, however, such processes were exposed to 5.0 mg/L PCP dose, enhanced phosphorus removal ceased and never returned.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.23 no.2
• /
• pp.13-19
• /
• 2019

Purpose Tc-99m HMPAO is widely used radiopharmaceutical for brain perfusion SPECT. Tc-99m HMPAO is chemically unstable and is liable to show deterioration of labeling efficiency due to high incidence of secondary Tc-99m HMPAO complex, free pertechnetate and reduced-hydrolyzed Tc-99m. In this study, we investigated whether sialogogues administration could reduce the impurities of Tc-99m HMPAO. Materials and Methods In thirty subjects(20 male and 10 female, age range 19~89 years, mean age $60.7{\pm}14.5years$), brain perfusion SPECT were performed at basal and citric acid stimulation states consecutively after injection of 555 MBq of Tc-99m HMPAO. In the salivary glands, the uptake coefficient was calculated using Siemens processing program. Statistical comparison between before and after the citric acid stimulation performed paired t-test. P value less than 0.05 was regarded as statistically significant. Results Salivary glands uptake was $12900{\pm}3101$ counts in basal and $10677{\pm}2742$ counts in citric acid stimulation states. Unnecessary impurities in the body is much decreased after citric acid administration(t=10.78, P<0.05). The image quality was much improved after administration of citric acid and the regional cerebral perfusion was clearly from demarcated the background. Conclusion The impurity is distributed throughout the body particularly in the salivary glands and nasal mucosa when Tc-99m HMPAO brain perfusion SPECT is performed. If this impurities is not removed, the quality of the image may deteriorate, resulting in errors in visual evaluation. The use of sialogogues could be helpful for decreasing unnecessary impurities in the body.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.17 no.6
• /
• pp.105-114
• /
• 2022

The purpose of this study is to analyze the influence of the nation's institutional environment on start-up intention of employees and the mediating role of risk-taking propensity in the relationship between these variables. This study classified the institutional environment into institutional profile regulation, institutional profile norms, and institutional profile recognition. The research data were collected through questionnaires for office workers belonging to domestic companies, and 322 copies of questionnaire data were used for hypothesis verification, except for questionnaires that were omitted or unfaithful. The results of this study are as follows. First, institutional profile regulations and norms were positively related to start-up intention of office workers, while institutional profile cognition had no significant effect on the start-up intention. Second, institutional profile regulations and norms were positively related to risk taking, while institutional profile cognition had no significant effect on risk taking. Finally, risk taking was found to partially mediate the relationship between institutional profile regulation and start-up intention, and completely mediate the relationship between institutional profile norms and start-up intention. The theoretical implications of this study are as follows. First, this study makes a theoretical contribution in that it revealed that the country institutional profile regulation and norms are important prerequisites for start-up intention and risk taking. Next, unlike previous studies, this study makes a theoretical contribution by presenting a start-up intention model of office workers consisting of perception of the institutional environment and risk taking, which is the individual characteristic of entrepreneurs. The practical implications of this study are as follows. First, the government and local governments should strengthen regulations on institutional profiles so that start-ups can be activated. Second, the government and local governments should strengthen the norms for institutional profiles so that start-ups can be activated. Finally, the government, local governments, and educational institutions should devise measures to strengthen the risk taking of start-ups.