• Proceedings of the Korea Society for Industrial Systems Conference
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• 2000.11a
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• pp.231-231
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• 2000

인터넷기업들은 불과 몇 달 전만 해도 수수께끼로 가득 찬 요지경이었다. 매출액은 늘어났지만 더 많은 손실이 발생했고, 엄청난 적자와는 정반대로 주가는 연일 상승곡선을 그리고 있었다. 오히려 손실을 줄이는 방안을 발표하면 주가가 떨어지는 기현상마저 보여 구경제의 질서에 익숙해 있던 투자자들이나 경영자들을 혼란스럽게 만들고 있다. 그런데 이처럼 높게 평가되던 인터넷 기업들의 주가가 최근에 들어 폭락하고 있다. eToys의 경우 주가가 최고치 였던 ＄86에서 94% 폭락한 ＄4.75에 거래되었고, CDNow는 83%, Buy.com은 81% 등 주요 온라인 업체들의 주가가 80% 이상 하락하였으며 그 외의 적지 않은 인터넷 기업들의 주가 역시 전성기에 비해 90-95%까지 폭락하였다. 이러한 이유로 최근 인터넷기업들의 정확한 가치평가를 하기 위한 연구들이 시도되고 있으며, 이러한 시도 중 비교적 객관적인 정보인 재무정보들을 이용하기 위한 연구들도 있다. 하지만 아직까지는 우리나라의 재무제표들이 제공하는 정보들이 부족하고 IMF이후 비정상적인 주가 등으로 인하여 실증하는데 어려움이 따르고 있다. 또한 인터넷 기업들은 전술한 바와 같이 기존 오프라인상의 제조업형태의 기업들처럼 일반적인 재무제표분석을 통한 가치평가에 어려움을 겪고 있다. 하지만 인터넷을 기반으로 한 디지털 경제에서도 오프라인기업에서와 똑같은 현상이 발생한다는 사실을 간과해서는 안 된다. 현금지출이 도달 가능한 현금유입의 수준을 넘어선다면 결국 도산하는 것은 인터넷기업들도 마찬가지이다. 현재 어떤 기업에 투자하는 것은 그 기업의 미래 현금흐름을 구매하고자 하는 것이다. 따라서 미래의 현금흐름이 커질수록 그 기업의 가치는 상승하게 된다. 현금흐름 분석이 특히 중요한 이유는 기업의 미래 현금흐름을 기업의 타인자본비용과 자기자본비용의 조합인 기회자본비용으로 할인함으로써 현재의 기업가치를 구할 수 있기 때문이다. 이처럼 기업이 영업활동이나 투자활동을 통해 현금을 창출하고 소비하는 경향은 해당 비즈니스 모델의 성격을 규정하는 자료도로 이용될 수 있다. 또한 최근 인터넷기업들의 부도가 발생하고 있는데, 기업의 부실원인이 어떤 것이든 사회전체의 생산력의 감소, 실업의 증가, 채권자 및 주주의 부의 감소, 심리적 불안으로 인한 경제활동의 위축, 기업 노하우의 소멸, 대외적 신용도의 하락 등과 같은 사회적·경제적 파급효과는 대단히 크다. 이상과 같은 기업부실의 효과를 고려할 때 부실기업을 미리 예측하는 일종의 조기경보장치를 갖는다는 것은 중요한 일이다. 현금흐름정보를 이용하여 기업의 부실을 예측하면 기업의 부실징후를 파악하는데 그치지 않고 부실의 원인을 파악하고 이에 대한 대응 전략을 수립하며 그 결과를 측정하는데 활용될 수도 있다. 따라서 본 연구에서는 기업의 부도예측 정보 중 현금흐름정보를 통하여 '인터넷기업의 미래 현금흐름측정, 부도예측신호효과, 부실원인파악, 비즈니스 모델의 성격규정 등을 할 수 있는가'를 검증하려고 한다.

• Fire Science and Engineering
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• v.13 no.1
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• pp.37-47
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• 1999

The spreading fire of very small floating particles after they are ignited is fast and t therefore dangerous. The research on this area has been limited to experiments and global simulations which treat them as dusts or gaseous fuel with certain concentration well m mixed with air. This research attempted micro-scale analysis of ignition of those particles modeling them as liquid droplets. For the beginning, the in-line array of fuel droplets is modeled by two-dimensional, unsteady conservation equations for mass, momentum, energy and species transport in the gas phase and an unsteady energy equation in the liquid phase. They are solved numerically in a generalized non-orthogonal coordinate. The single step chemical reaction with reaction rate controlled by Arrhenius’ law is assumed to a assess chemical reaction numerically. The calculated results show the variation of temperature and the concentration profile with time during evaporation and ignition process. Surrounding oxygen starts to mix with evaporating fuel vapor from the droplet. When the ignition condition is met, the exothermic reactions of the premixed gas initiate a and burn intensely. The maximum temperature position gradually approaches the droplet surface and maximum temperature increases rapidly following the ignition. The fuel and oxygen concentration distributions have minimum points near the peak temperature position. Therefore the moment of ignition seems to have a premixed-flame aspect. After this very short transient period minimum points are observed in the oxygen and fuel d distributions and the diffusion flame is established. The distance between droplets is an important parameter. Starting from far-away apart, when the distance between droplets decreases, the ignition-delay time decreases meaning faster ignition. When they are close and after the ignition, the maximum temperature moves away from the center line of the in-line array. It means that the oxygen at the center line is consumed rapidly and further supply is blocked by the flame. The study helped the understanding of the ignition of d droplet array and opened the possibility of further research.

• Applied Biological Chemistry
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• v.28 no.4
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• pp.261-270
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• 1985

This study was carried out he effects of water activity on the nonenzymatic browning reactions of dry milk powders. Samples (Dry Whole Milk DWM, Nonfat Dry Milk NFDM) stored at $55^{\circ}C$ were analyzed for $O_2,\;CO_2$ and $H_2O$ by Gas chromatographic method. The brown color which developed from the Maillard reaction was also measured by a reflective spectrophotometer. And linear regression equations and the correlation coeffcients were determined for $O_2,\;CO_2$ and brown color vs. storage, and the results are as follows. The amount of brown and off-flavor development increase as the water activities increase about 0.44 Aw during storage. Both DWM and NFDM milk products show a plateau in water absorption between the 0.33 and 0.44 water activities. DWM produced more browning than NFDM which may be partially due to the carbonyl amine reaction. The $CaCl_2$ solution may exude a water activity lower than 0.44 and varies greatly with temperatures. Oxygen is depleted as brown color development.

• The Journal of the Korea Contents Association
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• v.22 no.8
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• pp.527-541
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• 2022

The purpose of this study is to explore the economic hardship experiences of low-income single-parent families by COVID-19 to find ways to improve after COVID-19. To this end, 10 single parents with children under the secondary school age were recruited through snowball sampling method and in-depth interviews with economic activities, income, expenditure, and economic life. As a result of the study, participants suffered from unemployment and the disappearance of extra income activities in the early stages of COVID-19, additional expenses incurred by children's food and increased utility bills. In addition, it was recognized that COVID-19 has come to be more difficult and unequal to single-parent families of low-income women. It was found that the temporary living difficulties were resolved with disaster support funds, and it was helpful in the short term by spending according to priorities such as overdue monthly rent, food expenses, children's academy expenses, and purchasing home appliances. However, it was recognized that disaster support funds were inappropriate for customized disaster support and long-term and selective support was necessary. In the conclusion, to improve economic problems after COVID-19, it proposed measures to improve social welfare policies and practices

• Journal of Chest Surgery
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• v.34 no.6
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• pp.485-489
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• 2001

Background: The most important factor in preventing sternal complications is stable sternal approximation. We have tried to find the most effective sternal closure method by examining the incidence of sternal dehiscence with or without infection in patients with cardiac surgery through median sternotomy. Material and Method: This study was performed in 489 patients over 45 years of age with median sternotomy for open cardiac surgery. Simple closure with interrupted 6 wires was performed in 159 patients, figure-of-8 closure technique in 119, overlapping interrupted closure using 10 wires in 150, and combined closure technique of interrupted simple closure and figure-of-8 suture closure in 61. Two hundred thirty-four patients underwent valve and aortic operations and 213 patients coronary artery bypass surgery. Result: Sternal dehiscence with or without infection occurred in 12 (2.5 %) patients. The complication developed in 5 of 159 patients (3.1%) with six interrupted simple closure, in 4 of 119 patients (3.4%) with figure-of-8 closure, and in 3 of 150 patients (2.0%) with overlapping interrupted closure using 10 wires, but there was no complication in 61 patients with combined closure technique (relative risk for other closure techniques, p<0.05). There was no significant difference in the incidence of the sternal complication between valve and aortic operation group and coronary artery bypass group (3.0% vs 2.3%, not significant), but diabetes mellitus was a significant independent risk factor (odds ratio and multivariate analysis, p<0.05). Conclusion: The sternal closure technique that combines simple interrupted suture closure and figure-of-8 suture closure may be a more useful technique to enhance sternal stabilization compared to other closure techniques, such as simple interrupted closure, 8-figure closure, and overlapping interrupted closure.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.5
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• pp.457-464
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• 2001

Algal growth potential (AGP) assay using Cochlodinium polykrikoides was conducted in Saryang Island coast where C. polykrikoides red tide occurred annually from July to October 1998. The effects of macro- and micro-nutrients on the growth of C. polykrikoides were specifically evaluated by the algal assay method. Two different types of growth response of C. polykikoides for the addition of nutrients were clearly obseued. For both before and after C. polykrikoides occurrence, the growth of C. polykikoides was significantly stimulated by the addition of either nitrate or ammonium of $50{\mu]M$ with phosphate of $5{\mu}M$. The addition of a single nutrient had no clear effect on the growth of C. polyhikoides and the addition of trace metals, vitamins, and EDTA etc. did not stimulate the algal growth, also. This result indicates that both N and P potentially limited the growth of C. polyhikoides in this period. However, during a bloom of C. polyhikoides, the growth was unlikely to be stimulated by the addition of both macro- and micro-nutrients. At that time the nutrient concentration of Saryang Island coast was $24.33{\mu}M$ for ammonium, $1.61{\mu}M$ for phosphate, and $0.58{\mu}M$ for nitrate, respectively. The concentrations of nutrients increased, on average, 8.2-fold for ammonium and 4.8-fold for phosphate, decreased 3.3-fold for nitrate compared to both before and after the red tide. This result shows that the growth of C. polykikoides was not limited by the nutrients during the bloom in September. Therefore, our results suggest that the C. polykrikoides red tide may outbreak especially when the water is fertilized due to the increased N and P.

• Korean Journal of Ecology and Environment
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• v.47 no.2
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• pp.116-126
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• 2014

To evaluate the relationship between dynamics of Cyanobacterial bloom and rainfalls, a monthly monitoring of water quality and phytoplankton from the three serial lakes (Lake Ui-am, Lake Chung-pyeong and Lake Pal-dang) in the North Han River System were examined 12 times from May 2012 to March 2013. A dense bloom of cyanobacterium Anabaena spp., was occurred over three lakes in the summer season of 2012. In Lake Ui-am, the Anabaena population appeared in June, showed a peak in July (43,850 cells $mL^{-1}$) and disappeared in November 2012. In Lake Chung-pyeong and Lake Pal-dang, Anabaena population commonly appeared in July, showed the peaks (31,648 cells $mL^{-1}$ and 7,136 cells $mL^{-1}$, respectively) in August, and entirely disappeared in September 2012. Over the three lakes, the phytoplankton community was commonly dominated by diatoms before Monsoon, cyanobacteria during Monsoon, and diatoms after Monsoon, respectively, indicating a Monsoon-dependent succession. A correlation analysis revealed that dynamics of Anabaena population was strongly related with rainfall (r=0.72, r=0.83, r=0.88, P<0.01 for three lakes), and partly with nutrients, inflow and outflow of lakes. Therefore, this study indicates that the outbreak and destruction of Anabaena bloom in North Han River System between 2012 and 2013 was impacted by rainfalls. However, a high density of cyanobacteria in Lake Ui-am remained after Monsoon, and thus, may paroduce bad-order and toxins from phytoplankton.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.4
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• pp.389-396
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• 1994

Poor establishment of white dover (Trifolium repens L.) into grass-dominant pastures has been limited its availability. The experiment was done to clarify the effects of timing of initial defoliation, defoliation frequency on the regrowth and nodule formation of the clover cultivars during 28-day regrowing period. Individual plants of cv. Regal, Louisiana S-1 (La. S-1), Grasslands Huia (Huia) and Aberystwyth S184 (S184) were grown in containers until grown to unifoliolate, 1, 2, 4, or 8 trifoliolate stage, and then clipped to 1cm in height every 7 or 28 day for 28 days. To measure the effects, plants were sampled immediately after final harvest, and 1, 3, 7, 14 and 28 days after the harvest. Shoot, root dry weight and biomass were reduced with earlier, more frequent defoliation or shorter regrowing period. In frequent defoliation shoot dry weight and biomass were increased with delayed initial defoliation while in less frequent defoliation steeply done when initial defoliation was delayed to 4 trifoliolate stage. Shoot /Root ratio inclined with more frequent defoliation or lengthened regrowing period, and was greater in initial defoliation of unifoliolate to 2 trifoliolate than the others. Although nodules no. per plant declined with earlier or more frequent defoliation, the effect disappeared to some extent after 14-day regrowth. In comparison with the others, Regal had the highest shoot. dry weight and biomass to 2 trifoliolate stage while S184 did the most nodules regardless of defoliation timing. On 7-day after last defoliation nodule formation of Regal, Huia and S184 but on 28-day after last defoliation that of La. S-1, Huia and S184 was positively correlated to shoot and root dry weights upto 2 trifoliolate stage. On the former day, however, that was negatively correlated to Shoot /Root ratio upto 1 trifoliolate stage although on the latter day it was not, meaning that in addition to more frequent defoliation earlier defoliation was harmful in nodule formation of white clover.

• Korean Journal of Veterinary Research
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• v.34 no.4
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• pp.745-757
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• 1994

Superovulatory treatment with exogenous gonadotropins adversely affects the uterus through the disruption of the delicate balance of ovarian steroids (estrogens, progestins, androgens). To examine the uterine effects of this treatment, 189 rats were given 4IU, 20IU or 40IU pregnant mare',s serum gonadotropin(PMSG) at 28 days of age and sacrificed every 24h until day 10(D10) post injection. Long term uterine effects were examined in 12 rats treated with 4IU or 40IU PMSG and killed on D30. Adult rat uteri were examined to provide a reference for comparisons. Morphological and histological changes of control (4IU) uteri mimicked those of the adult on a comparable time-course form D2 to D5. Administration of superovulatory doses(20IU, 40IU) of PMSG produced stromal hypertrophy by D2 and focal papillary hyperplasia of the luminal epithelia by D3. Levels of $17{\beta}$-estradiol following 20IU and 40IU PMSG treatment were significantly(p<0.05, p<0.005) elevated above those of controls after D1. Androgen levels of both groups(20IU, 40IU) significantly p<0.05, p<005 increased from baseline on D1 and were maximum between D2 and D3. In the 20IU PMSG group, the hyperplasia gradually regressed after D3 and was absent by D10. The hyperplasia in the 40IU PMSG group, however, had become extensive by D6. It is suspected that preceding elevated levels of estrogen may be responsible for this progressive change. On D 4, the levels of $17{\beta}$-estradiol reached a maximum, which was significantly(p<0.001) greater than both the controls and 20IU PMSG-treated rats. Between D6 and D10, the hyperplasia in 40IU PMSG-treated rats partially regressed. Examination of uteri from D30 revealed no evidence of the hyperplasia. It is suggested that previous exposure to high levels of estrogen and androgens, secondary to superovulation, is possible cause for the observed hyperplasia.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.1
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• pp.16-26
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• 2000

Physical characteristics and nutrient distributions in seawater were investigated to understand the mechanism of red tide outbreak in coastal waters off Kohung area. To identify any physical and chemical differences before, during and after the red tide outbreaks, 6 times of field observations have been carried out from May to October, 1997. We found that major environmental properties of the seawater in the study area were determined not by the local meteoric conditions or nearby-land influences, but by the intrusion of seawater from offshore. In particular, extreme environmental variations in seawater were found during the period of red tide outbreak from August to September. Before the red tide outbreak, high concentrations of DIN(Dissolved Inorganic Nitrogen)were found in seawater, but they decreased during the outbreak. Whereas no significant variations of DIP(Dissolved Inorganic Phosphate) were found. For the water mass in the semienclosed northern part of the study area, local nutrient sources originated from nearby-lands were estimated to cover 70% of total DIN input, but the rest part of the water mass in the study area, sporadic intrusion of offshore water mass could account for the major source of DIN supply. An offshore water mass influenced by Yangtze river effluent was suggested as one of the candidates with its high nitrate contents, high seawater temperature and low salinity. A red tide related phytoplankton, Gyrodinium impudicum, was found in seawater on the 21th day of August and, on the same day, a unique water mass with high temperature and extremely low salinity suddenly appeared in the study area. On the 22th day of September, after one and half month duration of red tide we found that red tide had disappeared simultaneously with the intrusion of new water mass with different characteristics.