• Journal of Korean Society of Transportation
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• v.29 no.2
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• pp.25-35
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• 2011

In order to reduce Green House Gas(GHG) reduction in the road freight sector and thus establish green logistics, running efficiency of goods vehicles is of paramount importance. Providing effective transportation infrastructure can contribute to achieve the green logistics by reducing empty running of heavy goods vehicles and van, increasing the average payload on the vehicle, and shifting the transportation mode. In order to reduce the environmental impact from the road freight sector, it is essential to quantify the amount of environmental loading from the sector. However, any systematic survey on the environmental loading from the logistics companies has not been carried out in Korea. In this study, the environmental index for the road freight sector is defined as the amount of $CO_2$ emission per ton km generated from goods vehicles. The computational analysis shows that the average $CO_2$ emission per ton km generated by the logistics companies in Korea is $363g-CO_2/ton{\cdot}km$. Compared to UK (=$130g-CO_2/ton{\cdot}km$) and France (=$97g-CO_2/ton{\cdot}km$), the efficiency of logistics in Korea is 2.8 and 3.7 times as low as in the advanced countries. It also indicates that the main reasons for the low efficiency are mainly due to the high rate of empty operation of goods vehicles and the low payload.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.6
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• pp.601-609
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• 2017

Hydrogen is a clean, endlessly produced energy and it is easy to store and transfer. So, hydrogen is regarded as next generation energy. Among various ways for hydrogen production, the way to produce hydrogen by water electrolysis can effectively respond to fossil fuel's depletion or climate change. As interest in hydrogen has increased, related research has been actively conducted in many countries. In this study, we analyzed the performance characteristics and safety of water electrolysis system. In this study, we analyzed the performance characteristics and safety of water electrolysis system. The items for safety performance evaluation of the water electrolysis system were derived through analysis of international regulations, codes, and standards on hydrogen. Also, a prototype of the overall safety performance evaluation station was designed and developed. The demonstration test was performed with a prototype $10Nm^3/h$ class water electrolysis system that operated stably under various pressure conditions while measuring the stack and system efficiency. At 0.7MPa, the efficiency of the alkaline water electrolysis stack and the system that used in this study was 76.3% and 49.8% respectively. Through the GC analysis in produced $H_2$, the $N_2$ (5,157ppm) and $O_2$ (1,646 ppm) among Ar, $O_2$, $N_2$, CO and $CO_2$ confirmed as main impurities. It can be possible that the result of this study can apply to establish the safety standards for the hydrogen production system by water electrolysis.

• KSBB Journal
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• v.11 no.1
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• pp.77-85
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• 1996

The optimal initial pH for the ethanol production by Saccharomyces K35 was found to be 5.0, and about 80% of yield was obtained when 200g/$\ell$ of glucose was used as a substrate, which showed sugar tolerant. As the additives and cross-linking agent, the addition of 1.67%(w/v) Celite R-634 together with 0.33%(v/v) of glutaraldehyde(ACG bead) resulted in better stability, ethanol productivity and cell viability than Ca-alginate bead. Also, ACG bead seemed to be more resistant to phosphate ion than Ca-alginate bead, considering outgrowing cell concentration in the media. Scanning electron microscopic observation depicted that the surface of ACG bead was almost similar to the original state but not for Ca-alginate bead. When repealpd-batch culture was performed with Ca-alginate bead for 60 days in a 500m1 Erlenmeyer flask, ethanol and cell concentration were maintained about 138g/$\ell$-gel and 29~30g/$\ell$-gel, respectively, up to 40 days(7th run number), and then both were rapidly decreased. In the case of ACG bead, ethanol and cell concentration were maintained about 130~150g/$\ell$-gel and 32~35g/$\ell$-gel, respectively, up to 60days(10th run number). Cell viability was maintained about 70%, and outgrowing cell concentration was below 5.8% of total cell concentration.

• Journal of Korean Society of Forest Science
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• v.96 no.1
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• pp.48-53
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• 2007

This study was carried out to investigate the effect of $NO_3{^-}$ and $NH_4{^+}$ on the adventitious root growth and eleuthroside synthesis of Eleutherococcus senticosus during 3 L-bioreactor culture. The change of medium component ratio was also measured during culture. The fresh weignt of adventitious root reached to the greatest level of 24.4g FW/L in the presence of 50 mM $NO_3{^-}$ and 10 mM $NH_4{^+}$, representing 3.4-fold increase compared to the 60 mM $NH_4{^+}$. However, as the increase of the portion of $NH_4{^+}$, the root growth was decreased. Maximum eleutheroside B and E1 production were $249{\mu}g/g$ and $43{\mu}g/g$, respectively, with 30 mM total nitrogen source. The maximum production of eleutheroside E were $788{\mu}g/g$ with 120 mM total nitrogen source. The greatest weight of adventitious root increased up to 6.2 fold of inoculum size within 9 weeks. The change of pH was influenced from 4.81 to 6.35 and the amounts of $NH_4{^+}$ and $K^+$ were decreased during culture periods. From these results we suggest, need further study of various treatment to increase the growth of biomass and the accumulation of useful secondary metabilites.

• Journal of Yeungnam Medical Science
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• v.11 no.1
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• pp.127-134
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• 1994

The aim of this study was to identify the usefulness of pelviscopy in treatment besides its diagnostic value. The advantages of pelviscopic surgery are low cost, rapid recovery, good cosmetic effect, low incidence of complication and postoperative adhesion. So most of the pelvic exploration in gynecologic patients are replaced by the pelviscopic surgery these days. Pelviscopic surgery was performed on 136 patients at the Department of Obstetrics and Gynecology, College of Medicine, Yeungnam University from May 1991 to July 1993. The results obtained were as follows : The age distribution of the patients was from 19 to 55 with age of 31.2 years, and the mean parity was 0.96, the most common indication of pelviscopic surgery was tubal pregnancy(66.9%), the second most common indications was ovarian cyst(10.3%) and the other indications were endometriosis, corpus luteum cyst rupture, parovarian cyst, foreign body, tubal ligation, hydrosalpinx, uterine myoma and diagnostic procedure. The main types of surgery were salpingectomy in 58.8% and salpingoophorectomy in 16.3%. The mean duration of hospitalization was 2.1 days without specific complications. According to these results, it was postulated that the pelviscopic surgery was a useful operative tool in gynecologic treatment and its application could be extended to many other areas of gynecology with safety by the development of surgical techniques and instruments.

• Progress in Medical Physics
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• v.16 no.3
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• pp.111-115
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• 2005

We have designed the multi channel detector for the quality assurance of clinical photon beams. The detector was composed of solid phantom inserted by six plane-parallel ionization chambers at different depth. The chamber as a mini plane parallel chamber was made of carbon coated microfilms. In this study the electrical characteristics of the six chambers in the solid phantom were evaluated using 6 MV photon beam. The leakage currents were less than 0.5 pA, reproducibility was less than 0.5$\%$, linearity was less than 0.5$\%$, and dose rate effect was less than 0.7$\%$. In addition the effect of dose variation from other chambers was estimated to maximum 0.8$\%$ approximately. The developed detector can be used for quality determination in output dosimetry or measurement of percentage depth dose approximately for clinical photon beam.

• The Korean Journal of Nuclear Medicine
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• v.19 no.1
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• pp.119-126
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• 1985

To evaluate the performance characteristics of CA 19-9 radioimmunoassay and the clinical significance of serum CA 19-9 assay in patients with malignancy, serum CA 19-9 levels were measured by radioimmunoassay using monoclonal antibody in 135 normal controls, 81 patients with various untreated malignancy, 9 patients of postoperative colon cancer without recurrence and 20 patients with benign gastrointestinal diseases, who visited Seoul National University Hospital from June, 1984 to March, 1985. The results were as follows; 1) The CA 19-9 radioimmunoassay was simple to perform and can be completed in one work day. And the between-assay reproducibility and the assay recovery were both excellent. 2) The mean serum CA 19-9 level in 135 normal controls was $8.4{\pm}4.2U/mL$. Normal upper limit of serum CA 19-9 was defined as 21.0 U/mL. 4 out of 135(3.0%) normal controls showed elevated CA 19-9 levels above the normal upper limit. 3) One out of 20(5.0%) patients with benign gastrointestinal diseases showed elevated serum CA 19-9 level above the normal upper limit. 4) In 81 patients with various' untreated malignancy, 41 patients(50.6%) showed elevated serum CA 19-9 levels. 66.7% of 18 patients with colorectal cancer, 100% of 2 patients with pancreatic cancer, 100% of 3 patients with common bile duct cancer, 47.1% of 17 patients with stomach cancer, 28.6% of 28 patients with hepatoma and 60.0% of 5 other gastrointestinal tract cancers showed elevated serum CA 19-9 levels. 5) The sensitivities of serum CA 19-9 related to resectability in colorectal and stomach cancer were 33.3% in resectable colorectal cancer, 83.3% in unresectable colorectal cancer, 41.7% in resectable stomach cancer, 60.0% in unresectable stomach cancer respectively. 6) The sensitivity of serum CA 19-9 in 9 patients of postoperative colorectal cancer without recurrence were 33.3% and significantly decreased compared with that of untreated colorectal cancer, 66.7% (p<0.05). 7) In patients with colorectal cancer, simultaneous measurement of serum CA 19-9 and serum CEA levels increased sensitivities. From above results, we concluded that serum CA 19-9 radioimmunoassay is simple to perform and reproducible, and is a useful indicator reflecting tumor extent and responses to the treatment in patients with malignancy.

• Journal of Yeungnam Medical Science
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• v.15 no.1
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• pp.135-142
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• 1998

Maternal weight gain during pregnancy has been consistently associated with infant birth weight and pregnancy outcome. Our purpose was to determine the relationship between maternal weight gain pattern and birth weight. Consequently, maternal weight gain is monitored carefully and is encouraged during prenatal care in order to improve pregnancy outcome. Our study group included both 424 uncomplicated women and infant delivered at the Yeungnam University Hospital between 1993-1996. All recorded prenatal weight gain measurements were used to estimate maternal trimester weight gain, pattern of gain (based on low versus not-low gain at each trimester), and total gain at delivery. Multiple linear regression analysis was used to assess the relationship between these weight gain measurements and fetal birth weight. Each kilogram of maternal gain in the first, second, and third trimesters was associated with statistically related to the increase in fetal birth weight by 31.3, 19.0, and 24.5g, respectively. When compaired with the pattern of gain that was not low in any trimester, patterns with low gain in the first trimesters were associated with significant decreases in birth weight, but no important change in birth weight was seen for the group whose gains were not low in the first trimester. The results suggest that specific patterns of maternal weight gain, particularly weight gain during the first trimester, are related to fetal birth weight.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.2
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• pp.63-69
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• 2013

Change detection technique is essential to various applications of Very High-Resolution(VHR) satellite imagery and land monitoring. However, change detection accuracy of VHR satellite imagery can be decreased due to various geometrical dissimilarity. In this paper, the existing fusion evaluation indexes were revised and applied to improve VHR imagery based change detection accuracy between multi-temporal images. In addition, appropriate change detection methodology of VHR images are proposed through comparison of general change detection algorithm with cross-sharpened image based change detection algorithm. For these purpose, ERGAS, UIQI and SAM, which were representative fusion evaluation index, were applied to unsupervised change detection, and then, these were compared with CVA based change detection result. Methodologies for minimizing the geometrical error of change detection algorithm are analyzed through evaluation of change detection accuracy corresponding to image fusion method, also. The experimental results are shown that change detection accuracy based on ERGAS index by using cross-sharpened images is higher than these based on other estimation index by using general fused image.

• Journal of Distribution Science
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• v.16 no.2
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• pp.89-99
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• 2018

Purpose - In this study, we discuss the current status and barriers of digital transformation focused on small businesses. More specifically, this study consists of two studies. The purpose of study 1 is to investigate the effect of digitization of small businesses on the sales of stores and the number of visiting customers. The purpose of Study 2 is to examine the status and obstacles of online channels use by small businesses. Research design, data, and methodology - In Study 1, we will examine the changes in sales and visitor numbers of stores that are rapidly adapting to digital transformation among small business. For this, we utilize the actual situation of store management survey conducted by the Small Enterprise and Market Service. Specifically, multiple regression equations were used to determine whether blogs and online shopping malls were operating, and the proportion of credit cards to sales as independent variables and sales and number of visiting customers as dependent variables. Next, in Study 2, we surveyed the 15 small business owners in the latest survey on the actual situation of store management survey conducted in 2015, and conducted an in-depth interview to examine the barriers to the use of online channels by small business. Results - As a result of study 1, it is found that the small business who run the blogs have higher sales and visits than the small business who do not. However, there is no difference in the sales and the number of visiting customers between the stores that operate the online shopping malls and those that do not. Second, the higher the proportion of credit cards, the higher the sales and the number of visiting customers. In study 2, we analyzed the barriers to the expansion of online channels by in-depth interviews. Interviews show that barriers to access to online channels are limited by search neutrality, high commission burden, and low bargaining power. These problems are caused by the insufficiency of small business compared to online and mobile portal and O2O platform vendors. Conclusions - This study suggests that small business who have difficulty in establishing direct online channels need digital transformation of small business. In addition, when using such an external platform, we have identified the problems that small business face.