• KDI Journal of Economic Policy
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• v.12 no.2
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• pp.95-120
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• 1990

The underpricing of new shares of a firm that are offered to the public for the first time (initial offerings) is well known and has puzzled financial economists for a long time since it seems at odds with the optimal behavior of the owners of issuing firms. Past attempts by financial economists to explain this phenomenon have not been successful in the sense that the explanations given by them are either inconsistent with the equilibrium theory or implausible. Approaches by such authors as Welch or Allen and Faulhaber are no exceptions. In this paper, we develop a signalling model of capital investment to explain the underpricing phenomenon and also analyze the efficiency of investment. The model focuses on the information asymmetry between the owners of issuing firms and general investors. We consider a firm that has been owned and operated by a single owner and that has a profitable project but has no capital to develop it. The profit from the project depends on the capital invested in the project as well as a profitability parameter. The model also assumes that the financial market is represented by a single investor who maximizes the expected wealth. The owner has superior information as to the value of the firm to investors in the sense that it knows the true value of the parameter while investors have only a probability distribution about the parameter. The owner offers the representative investor a fraction of the ownership of the firm in return for a certain amount of investment in the firm. This offer condition is equivalent to the usual offer condition consisting of the number of issues to sell and the unit price of a share. Thus, the model is a signalling game. Using Kreps' criterion as the solution concept, we obtained an essentially unique separating equilibrium offer condition. Analysis of this separating equilibrium shows that the owner of the firm with high profitability chooses an offer condition that raises an amount of capital that is short of the amount that maximizes the potential profit from the project. It also reveals that the fraction of the ownership of the firm that the representative investor receives from the owner of the highly profitable firm in return for its investment has a value that exceeds the investment. In other words, the initial offering in the model is underpriced when the profitability of the firm is high. The source of underpricing and underinvestment is the signalling activity by the owner of the highly profitable firm who attempts to convince investors that his firm has a highly profitable project by choosing an offer condition that cannot be imitated by the owner of a firm with low profitability. Thus, we obtained two main results. First, underpricing is a result of a signalling activity by the owner of a firm with high profitability when there exists information asymmetry between the owner of the issuing firm and investors. Second, such information asymmetry also leads to underinvestment in a highly profitable project. Those results clearly show the underpricing entails underinvestment and that information asymmetry leads to a social cost as well as a private cost. The above results are quite general in the sense that they are based upon a neoclassical profit function and full rationality of economic agents. We believe that the results of this paper can be used as a basis for further research on the capital investment process. For instance, one can view the results of this paper as a subgame equilibrium in a larger game in which a firm chooses among diverse ways to raise capital. In addition, the method used in this paper can be used in analyzing a wide range of problems arising from information asymmetry that the Korean financial market faces.

• Journal of Chest Surgery
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• v.32 no.9
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• pp.806-812
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• 1999

Background: Selection of reconstruction route in esophageal cancer surgery is based on the patient's status, characteristics of tumor, surgeon's preference and experience. Of the various routes, it has been documented that subcutaneous or substernal route may prolong operation time and may be vulnerable to postoperative respiratory complications. This study was designed to evaluate whether the selection of reconstruction route affects the surgical outcomes. Material and Method: Of 131 patients who have undergone resection and reconstruction for esophageal cancer, posterior mediastinal route(Group I, n=34), substernal route (Group II, n=31), and subcutaneous route(Group III, n=21) were retrospectively reviewed in 86 patients. Results of early operations and morbidities were compared between the groups. Result: There was a male prevalence(79 of males vs. 7 of females). There were 81 squamous cell cancers and 5 adenocarcinomas. There were no differences between groups in weight, height, age, cancer staging and location, and in the preoperative anesthetic risk evaluation and pulmonary function test(p=NS). Postoperative mechanical ventilation time was longer in Group I(20.6 hours) than in Group II(7.8 hours) or III(3.4 hours)(p=0.005). Duration of stay in the intensive care unit was prolonged in Group III(6.4 days) compared to Group I (3.9 days) or II(3.1 days)(p=0.043). No differences were noted in the duration of hospital stay between the groups(p=NS). Blood transfusion was needed in 30 out of 34 patients in Group I compared to 14/31 in Group II or 15/21 in Group III(p=0.001). The mean amount of transfusion for each patient was also higher in Group I(3,833 mL) than in Group II(1535 mL) or Group III(1419 mL)(p=0.04), but there was no difference in the inreoperation due to bleeding. Ea ly mortality rate was substantially higher in Group I(17.6%) but the differences between the groups were insignificant(p=NS). Although sepsis was a more prevalent cause of death in Group I, it was not related to anastomotic leak. Other morbidities did not differ between the groups(p=NS). Conclusion: In above results show that the reconstruction route does not affect the outcome of esophageal cancer surgery. We believe that the selection of reconstruction route can be based on the surgeon's preference and experience.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.88-89
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• 2013

A variety of influenza A viruses from animal hosts are continuously prevalent throughout the world which cause human epidemics resulting millions of human infections and enormous industrial and economic damages. Thus, early diagnosis of such pathogen is of paramount importance for biomedical examination and public healthcare screening. To approach this issue, here we propose a fully integrated Rotary genetic analysis system, called Rotary Genetic Analyzer, for on-site detection of influenza A viruses with high speed. The Rotary Genetic Analyzer is made up of four parts including a disposable microchip, a servo motor for precise and high rate spinning of the chip, thermal blocks for temperature control, and a miniaturized optical fluorescence detector as shown Fig. 1. A thermal block made from duralumin is integrated with a film heater at the bottom and a resistance temperature detector (RTD) in the middle. For the efficient performance of RT-PCR, three thermal blocks are placed on the Rotary stage and the temperature of each block is corresponded to the thermal cycling, namely $95^{\circ}C$ (denature), $58^{\circ}C$ (annealing), and $72^{\circ}C$ (extension). Rotary RT-PCR was performed to amplify the target gene which was monitored by an optical fluorescent detector above the extension block. A disposable microdevice (10 cm diameter) consists of a solid-phase extraction based sample pretreatment unit, bead chamber, and 4 ${\mu}L$ of the PCR chamber as shown Fig. 2. The microchip is fabricated using a patterned polycarbonate (PC) sheet with 1 mm thickness and a PC film with 130 ${\mu}m$ thickness, which layers are thermally bonded at $138^{\circ}C$ using acetone vapour. Silicatreated microglass beads with 150~212 ${\mu}L$ diameter are introduced into the sample pretreatment chambers and held in place by weir structure for construction of solid-phase extraction system. Fig. 3 shows strobed images of sequential loading of three samples. Three samples were loaded into the reservoir simultaneously (Fig. 3A), then the influenza A H3N2 viral RNA sample was loaded at 5000 RPM for 10 sec (Fig. 3B). Washing buffer was followed at 5000 RPM for 5 min (Fig. 3C), and angular frequency was decreased to 100 RPM for siphon priming of PCR cocktail to the channel as shown in Figure 3D. Finally the PCR cocktail was loaded to the bead chamber at 2000 RPM for 10 sec, and then RPM was increased up to 5000 RPM for 1 min to obtain the as much as PCR cocktail containing the RNA template (Fig. 3E). In this system, the wastes from RNA samples and washing buffer were transported to the waste chamber, which is fully filled to the chamber with precise optimization. Then, the PCR cocktail was able to transport to the PCR chamber. Fig. 3F shows the final image of the sample pretreatment. PCR cocktail containing RNA template is successfully isolated from waste. To detect the influenza A H3N2 virus, the purified RNA with PCR cocktail in the PCR chamber was amplified by using performed the RNA capture on the proposed microdevice. The fluorescence images were described in Figure 4A at the 0, 40 cycles. The fluorescence signal (40 cycle) was drastically increased confirming the influenza A H3N2 virus. The real-time profiles were successfully obtained using the optical fluorescence detector as shown in Figure 4B. The Rotary PCR and off-chip PCR were compared with same amount of influenza A H3N2 virus. The Ct value of Rotary PCR was smaller than the off-chip PCR without contamination. The whole process of the sample pretreatment and RT-PCR could be accomplished in 30 min on the fully integrated Rotary Genetic Analyzer system. We have demonstrated a fully integrated and portable Rotary Genetic Analyzer for detection of the gene expression of influenza A virus, which has 'Sample-in-answer-out' capability including sample pretreatment, rotary amplification, and optical detection. Target gene amplification was real-time monitored using the integrated Rotary Genetic Analyzer system.

• Journal of Mushroom
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• v.17 no.3
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• pp.119-125
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• 2019

This study aims to report the results for the analysis of the growth environment by applying smart farm technology to "Chunchu No 2" farmers in order to develop an optimal growth model for precision cultivation of bottle-grown oyster mushrooms. The temperature, humidity, carbon dioxide concentration, and illumination data were collected and analyzed using an environmental sensor installed to obtain growth environment data from the oyster mushroom cultivator. Analysis of the collected temperature data revealed that the temperature at the time of granulation was $19.5^{\circ}C$ after scraping, and the mushroom was generated and maintained at about $21^{\circ}C$ until the bottle was flipped. When the fruiting body grew and approached harvest time, mushrooms were harvested while maintaining the temperature between $14^{\circ}C$ and $18^{\circ}C$. The humidity was maintained at almost 100% during the complete growth stage. Carbon dioxide concentration gradually increased until 3 days after the beginning of cultivation, and then increased rapidly to almost 5,500 ppm. From the 6th day, carbon dioxide concentration was gradually decreased through ventilation and was maintained at 1,600 ppm during harvest. Light intensity of 8 lux was irradiated up to day 6 after seeding, and growth was then continued while periodically irradiating 4 lux light. The fruiting body characteristics of "Chunchu No 2" cultivated in the farmhouse were as follows: pileus diameter of 26.5 mm and thickness of 4.9 mm, stipe thickness of 8.9 mm, and length of 68.7 mm. The fruiting body yield was 166.8 g/850 ml, and the individual weight was 12.8 g/10 units.

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.2
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• pp.29-37
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• 2019

Purpose DMIDR(Discovery Molecular Imaging Digital Ready, General Electric Healthcare, USA) is a PET/CT scanner designed to allow application of PSF(Point Spread Function), TOF(Time of Flight) and Q.Clear algorithm. Especially, Q.Clear is a reconstruction algorithm which can overcome the limitation of OSEM(Ordered Subset Expectation Maximization) and reduce the image noise based on voxel unit. The aim of this paper is to evaluate the performance of reconstruction algorithms and optimize the algorithm combination to improve the accurate SUV(Standardized Uptake Value) measurement and lesion detectability. Materials and Methods PET phantom was filled with $^{18}F-FDG$ radioactivity concentration ratio of hot to background was in a ratio of 2:1, 4:1 and 8:1. Scan was performed using the NEMA protocols. Scan data was reconstructed using combination of (1)VPFX(VUE point FX(TOF)), (2)VPHD-S(VUE Point HD+PSF), (3)VPFX-S (TOF+PSF), (4)QCHD-S-400((VUE Point HD+Q.Clear(${\beta}-strength$ 400)+PSF), (5)QCFX-S-400(TOF +Q.Clear(${\beta}-strength$ 400)+PSF), (6)QCHD-S-50(VUE Point HD+Q.Clear(${\beta}-strength$ 50)+PSF) and (7)QCFX-S-50(TOF+Q.Clear(${\beta}-strength$ 50)+PSF). CR(Contrast Recovery) and BV(Background Variability) were compared. Also, SNR(Signal to Noise Ratio) and RC(Recovery Coefficient) of counts and SUV were compared respectively. Results VPFX-S showed the highest CR value in sphere size of 10 and 13 mm, and QCFX-S-50 showed the highest value in spheres greater than 17 mm. In comparison of BV and SNR, QCFX-S-400 and QCHD-S-400 showed good results. The results of SUV measurement were proportional to the H/B ratio. RC for SUV is in inverse proportion to the H/B ratio and QCFX-S-50 showed highest value. In addition, reconstruction algorithm of Q.Clear using 400 of ${\beta}-strength$ showed lower value. Conclusion When higher ${\beta}-strength$ was applied Q.Clear showed better image quality by reducing the noise. On the contrary, lower ${\beta}-strength$ was applied Q.Clear showed that sharpness increase and PVE(Partial Volume Effect) decrease, so it is possible to measure SUV based on high RC comparing to conventional reconstruction conditions. An appropriate choice of these reconstruction algorithm can improve the accuracy and lesion detectability. In this reason, it is necessary to optimize the algorithm parameter according to the purpose.

• Korean Journal of Heritage: History & Science
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• v.34
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• pp.20-58
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• 2001

In order to unravel the characteristics of arms used in the 'Three Kingdoms,' Kokuryo, Silla and Paikje. the classification and the developing procedures of the arms should be first discussed. At first, the basic arms of the soldiers of Three Kingdoms were iron swords, iron spearheads, and bows. During that period, swords attached a ring pommel were commonly used. But after 5A. D. a sword with a decoration pommel appeared. Infantry generally used iron spearheads. From the late 4A. D. the long spearheads were broadly used in cavalry battles. In the late 6A. D. infantry mainly used long spearheads, and this resulted in the foundation of long spearheads units. There were two kinds of bows: Short Bow whose arch is small and Long Bow whose arch is long. It is known that the Short Bow was widely used in Kokuryo and Paikje up to 5A. D. In the early era, infantry used Long Bow, yet it was vastly used after 6A. D. when a castle's strategical value was great and defending a castle was. significant. Above mentioned, as basic combat weapons, iron spearhead and bow were fundamental. In particular, the spearhead was the essential weapon to a soldier. Yet, arrow gun and hook-shape cutters were important weapons. Especially, after 6A.D., when a castle became strategically pivotal in military, the arrow gun became the important weapon. This resulted in the foundation of arrow gun units. Hook-shape cutters were used to snatch horsemen or to climb up to fall the castle. Yet, the cutter was not the Three Kingodoms' basic weapon. In addition, the three stages of arms development in the Three Kingdoms are formation stage, development stage, and settlement stage. The formation stage was the period when premitive military unit appeared in the Three Kingdoms. It ranged from 1B. C. to the mid 3A. D. At that time according to regions. there were two weapon systems operating: North area including Kokuryo and the northern part of Paikje and South area including Silla, Kaya and the southern part of Paikje. ln North area a sword with a ring attached at the end of the holder, iron spear with neck and mid-size flat holder and iron arrowhead with an extension to fix, were used. In this period, during a war calvary units were mostly used and their weapon systems seemed possibly to succeed in that of Kochosun. In the development stage, when LoLang's influence on surroundings became weak, Koguryo, Paikjae and Silla had directly contacted each other. In the late 3A.D. to the early 6A.D., Silla achieved a drastic improvement in weapon system. This was the period when Kokuryo played a leading role in arms race. Kokuryo's arms manufacturing techniques passed onto Silla, Kaya and Paikje. In combat strategy a joint operation between infantry and calvary prevailed even if their military tactics were different. In a calvary battle heavily armed horsemen played import roles at this period. The horsemen and even horses were heavily guarded with iron armors. After all, the appearance of fully armed horsemen implies the very need of powerful destructive forces in weapon system. At that time, basic weapons were a big sword with a ring attached at the end of the holder, swallow's tail-shape spear with neck, and iron spearhead with neck and an extension. The settlement stage began at the mid 6A.D., when it was the revolutionary period in the arms development history. Of course, actual proofs and picture documents were not sufficient enough to penetrate full scale of the weapon system. But, according to historical circumstances and historic records, it is very certain that this period was the peak in arms development. In this period special military units, such as infantry-calvary companies, Archery units and Long spear units, that executed particular duties with special weapons, were founded. This became the characteristics of the settlement stage.

• The Korean Journal of Archival Studies
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• no.28
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• pp.3-33
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• 2011

The Office of Crown Properties was established to manage the property of royal properties as an institution belonging to the Department of the Royal Household in April, 1895. However, as the Great Han Empire established and various policies enforcing the power of the emperor became introduced, the Office of Crown Properties came to be expanded to a large financial agency that would be in charge of various financial sources such as Public Land and Maritime Tax. As the Office of Crown Properties came to manage various income sources, it classified the documents dealing with various government agencies in the Capital and other countryside regions by the unit of Section. The Office of Crown Properties classified the documents by Section and filed them according to Sending/Receiving subject. Sometimes, it filed one kind of document only but sometimes many different kinds of documents were filed together. The types of the document can show the characteristics of the document and the hierarchy of the related agencies through the document name. The fact that they filed the documents with different grades in one file shows that the hierarchy of the agency they dealt with was not the primary standard of the filing and that they did not file the documents by its type. The Office of Crown Properties did not file the related documents in the same file, either. We can say the documents are related if they were corresponded with other agencies while they dealt with a specific item. However, they did not file the related documents in the same file but distinguished sending documents from receiving documents. The reason why they filed different kind documents in the same file and separated the related documents in different file was they took 'whether they were sent or received' as the primary filing standard. They separated the sending documents from the receiving documents first and then filed them according to time regardless of the region or institution. The Office of Crown Properties primarily classified the documents by Section, classified the documents with the standard of whether they were receiving documents or sending documents and then filed them in a file according to the time. It means that the Office of Crown Properties came to create the Official Document Classification and filing system.

• Korean Journal of Heritage: History & Science
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• v.54 no.1
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• pp.238-259
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• 2021

Gameunsa Temple is a Buddhist temple from the mid-Silla period. Construction began during the reign of King Munmu and was completed during the second year of King Sinmun's reign (682). This study is based on the results of excavations at the Gameunsa Temple site, exploring the findings presented in the literature in the field of history. This study also investigates the characteristics of the construction plan of Gameunsa Temple and its correlation with the political, social, and religious environment of the time. The results of the study are as follows: (1) First, it is confirmed that all of the buildings in the central block of Gameunsa Temple, such as the pagoda and corridor, the central gate, and the auditorium, fit within 216 cheoks by 216 cheoks (Goguryeo unit of measurement, estimated dimensions 353.30 mm), in terms of the base structure. This fact is highly significant considering the intent of the King in the mid-Silla period to advocate Confucian political ideals at the Donghaegu sites (Daewangam, Igyeondae Pavilion, and Gameunsa Temple), as confirmed by the relationship between the 'Manpasikjeok legend' and the Confucianism of the etiquette and the music; the relationship between the name of the 'Igyeondae Pavilion' and the 'I Ching'; and the relationship between the 'Taegeuk stones excavated from the Gameunsa Temple site' and the 'I Ching.' Additionally, it may be presumed that the number in the "Qian 216" on the Xici shang of 'I Ching' was used as a basis for determining the size of the central block in the early stages of the design of Gameunsa Temple. The layout of the halls and pagodas of Gameunsa Temple was planned to be within a 216-cheok-by-216-cheok area, from the edge to the center, i.e., on the central axis of the temple, in the following order: the central gate and auditorium, the north-south position of Geumdang Hall, the south corridor, the east-west buildings of the auditorium and the winged corridor, the east-west corridor, and the central position of the east-west stone pagoda. (2) Second, the coexistence of Confucianism and Buddhism in the architecture of Gameunsa Temple is based on the understanding of the Golden Light Sutra, originating from the aspirations of King Munmu to obtain the immeasurable merits (陰陽調和時不越序 日月星宿不失常度 風雨隨時無諸災横) and the light of the Buddha, which is metaphorically represented by the sun and the moon illuminating the whole world of Silla, a new nation with a Confucian political ideology, for a long time by "circumambulating the Buddha (旋繞)". It is also presumed that Gyeongheung, who was appointed by King Munmu to be the Guksa in his will and appointed as the Gukro after the enthronement of King Sinmun, was deeply involved in the conception and realization of the syncretism of Confucianism and Buddhism.

• Journal of Bio-Environment Control
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• v.31 no.1
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• pp.22-27
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• 2022

The attraction effects of light emitting diode (LED) trap to Spodoptera exigua and Spodoptera litura adults were evaluated in greenhouse and compared with those of no light trap, which is typical used in commercial trap. At this time, in order to attract these two species of moths, sex pheromone traps were installed at the top side according to the degree of tomato growth inside the tomato cultivation greenhouse around the LED trap. In addition, two types of light-emitting traps (420 nm, 470 nm) were installed in the greenhouse at 1/40 m², respectively. Also two sex pheromone were installed inside of the greenhouse according to the height of the tomato plants. 10 days later, Blue-light trap(BLB, 470 nm wavelength) was 3.1-3.5 times more attractive than Violet-light trap(VLB, 420 nm wavelength) in S. exigua (105.6 ± 7.3) and S. litura (42.0 ± 3.1) respectively, whereas the no-light trap was little attractive to S. exigua (33.7 ± 2.8) and S. litura (12.0 ± 1.5). On the other hand, after the installation of the sex pheromone trap and the LED trap, there was no damage to S. litura (Fabricius) and S. exigua in the pesticide-free area, indicating a high possibility of control. At this time, the operating cost of the two types of LED traps was 80 won/m² per unit area, and it was confirmed that both types of moths could be controlled. In addition, as a result of confirming the number of two types of moths caught in the sexual pheromone trap and two types of LED traps after 4 months, it was judged that eco-friendly control was possible as more than 373 moths/trap were attracted to the two types of moths.

• The Journal of Engineering Geology
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• v.33 no.3
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• pp.371-388
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• 2023

A stratum with a complex composition and a distributed low-permeability soil layer is difficult to remediate quickly because the soil remediation does not proceed easily. For efficient purification, the permeability should be improved and the soil remediation agent (H₂O₂) should be injected into the contaminated section to make sufficient contact with the TPH (Total petroleum hydrocarbons). This study analyzed a method for crack formation and effective delivery of the soil remediation agent based on pneumatic fracturing, plasma blasting, and vacuum suction (the PPV method) and compared its improvement effect relative to chemical oxidation. A demonstration test confirmed the effective delivery of the soil remediation agent to a site contaminated with TPH. The injection amount and injection time were monitored to calculate the delivery characteristics and the range of influence, and electrical resistivity surveying qualitatively confirmed changes in the underground environment. Permeability tests also evaluated and compared the permeability changes for each method. The amount of soil remediation agent injected was increased by about 4.74 to 7.48 times in the experimental group (PPV method) compared with the control group (chemical oxidation); the PPV method allowed injection rates per unit time (L/min) about 5.00 to 7.54 times quicker than the control method. Electrical resistivity measurements assessed that in the PPV method, the diffusion of H₂O₂2 and other fluids to the surface soil layer reduced the low resistivity change ratio: the horizontal change ratio between the injection well and the extraction well decreased the resistivity by about 1.12 to 2.38 times. Quantitative evaluation of hydraulic conductivity at the end of the test found that the control group had 21.1% of the original hydraulic conductivity and the experimental group retained 81.3% of the initial value, close to the initial permeability coefficient. Calculated radii of influence based on the survey results showed that the results of the PPV method were improved by 220% on average compared with those of the control group.