• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.3
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• pp.82-98
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• 2019

The importance of spatial information is rapidly rising. In particular, 3D spatial information construction and modeling for Real World Objects, such as smart cities and digital twins, has become an important core technology. The constructed 3D spatial information is used in various fields such as land management, landscape analysis, environment and welfare service. Three-dimensional modeling with image has the hig visibility and reality of objects by generating texturing. However, some texturing might have occlusion area inevitably generated due to physical deposits such as roadside trees, adjacent objects, vehicles, banners, etc. at the time of acquiring image Such occlusion area is a major cause of the deterioration of reality and accuracy of the constructed 3D modeling. Various studies have been conducted to solve the occlusion area. Recently the researches of deep learning algorithm have been conducted for detecting and resolving the occlusion area. For deep learning algorithm, sufficient training data is required, and the collected training data quality directly affects the performance and the result of the deep learning. Therefore, this study analyzed the ability of detecting the occlusion area of the image using various image quality to verify the performance and the result of deep learning according to the quality of the learning data. An image containing an object that causes occlusion is generated for each artificial and quantified image quality and applied to the implemented deep learning algorithm. The study found that the image quality for adjusting brightness was lower at 0.56 detection ratio for brighter images and that the image quality for pixel size and artificial noise control decreased rapidly from images adjusted from the main image to the middle level. In the F-measure performance evaluation method, the change in noise-controlled image resolution was the highest at 0.53 points. The ability to detect occlusion zones by image quality will be used as a valuable criterion for actual application of deep learning in the future. In the acquiring image, it is expected to contribute a lot to the practical application of deep learning by providing a certain level of image acquisition.

• Journal of radiological science and technology
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• v.31 no.1
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• pp.17-23
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• 2008

Purpose : Because there is a difference depending on the environment as for an inspection equipment the important part of bone density scan and the precision/accuracy of a tester, the management of quality must be made systematically. The equipment failure caused by overload effect due to the aged equipment and the increase of a patient was made frequently. Thus, the replacement of equipment and additional purchases of new bonedensity equipment caused a compatibility problem in tracking patients. This study wants to know whether the clinical changes of patient's bonedensity can be accurately and precisely reflected when used it compatiblly like the existing equipment after equipment replacement and expansion. Materials and methods : Two equipments of GE Lunar Prodigy Advance(P1 and P2) and the Phantom HOLOGIC Spine Road(HSP) were used to measure equipment precision. Each device scans 20 times so that precision data was acquired from the phantom(Group 1). The precision of a tester was measured by shooting twice the same patient, every 15 members from each of the target equipment in 120 women(average age 48.78, 20-60 years old)(Group 2). In addition, the measurement of the precision of a tester and the cross-calibration data were made by scanning 20 times in each of the equipment using HSP, based on the data obtained from the management of quality using phantom(ASP) every morning (Group 3). The same patient was shot only once in one equipment alternately to make the measurement of the precision of a tester and the cross-calibration data in 120 women(average age 48.78, 20-60 years old)(Group 4). Results : It is steady equipment according to daily Q.C Data with $0.996\;g/cm^2$, change value(%CV) 0.08. The mean${\pm}$SD and a %CV price are ALP in Group 1(P1 : $1.064{\pm}0.002\;g/cm^2$, $%CV=0.190\;g/cm^2$, P2 : $1.061{\pm}0.003\;g/cm^2$, %CV=0.192). The mean${\pm}$SD and a %CV price are P1 : $1.187{\pm}0.002\;g/cm^2$, $%CV=0.164\;g/cm^2$, P2 : $1.198{\pm}0.002\;g/cm^2$, %CV=0.163 in Group 2. The average error${\pm}$2SD and %CV are P1 - (spine: $0.001{\pm}0.03\;g/cm^2$, %CV=0.94, Femur: $0.001{\pm}0.019\;g/cm^2$, %CV=0.96), P2 - (spine: $0.002{\pm}0.018\;g/cm^2$, %CV=0.55, Femur: $0.001{\pm}0.013\;g/cm^2$, %CV=0.48) in Group 3. The average error${\pm}2SD$, %CV, and r value was spine : $0.006{\pm}0.024\;g/cm^2$, %CV=0.86, r=0.995, Femur: $0{\pm}0.014\;g/cm^2$, %CV=0.54, r=0.998 in Group 4. Conclusion: Both LUNAR ASP CV% and HOLOGIC Spine Phantom are included in the normal range of error of ${\pm}2%$ defined in ISCD. BMD measurement keeps a relatively constant value, so showing excellent repeatability. The Phantom has homogeneous characteristics, but it has limitations to reflect the clinical part including variations in patient's body weight or body fat. As a result, it is believed that quality control using Phantom will be useful to check mis-calibration of the equipment used. A value measured a patient two times with one equipment, and that of double-crossed two equipment are all included within 2SD Value in the Bland - Altman Graph compared results of Group 3 with Group 4. The r value of 0.99 or higher in Linear regression analysis(Regression Analysis) indicated high precision and correlation. Therefore, it revealed that two compatible equipment did not affect in tracking the patients. Regular testing equipment and capabilities of a tester, then appropriate calibration will have to be achieved in order to calculate confidential BMD.

• The Korean Journal of Nuclear Medicine
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• v.39 no.6
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• pp.421-429
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• 2005

Purpose: It has been postulated that dopamine release in the striatum underlies the reinforcing properties of nicotine. Substantial evidence in the animal studies demonstrates that nicotine interacts with dopaminergic neuron and regulates the activation of the dopaminergic system. The aim of this study was to visualize the dopamine release by smoking in human brain using PET scan with $[^{11}C]raclopride$. Materials and Methods: Five male non-smokers or ex-smokers with an abstinence period longer than 1 year (mean age of $24.4{\pm}1.7$ years) were enrolled in this study $[^{11}C]raclopride$, a dopamine D2 receptor radioligand, was administrated with bolus-plus-constant infusion. Dynamic PET was performed during 120 minutes ($3{\times}20s,\;2{\times}60s,\;2{\times}120s,\;1{\times}180s\;and\;22{\times}300s$). following the 50 minute-scanning, subjects smoked a cigarette containing 1 mg of nicotine while in the scanner. Blood samples for the measurement of plasma nicotine level were collected at 0, 5, 10, 15, 20, 25, 30, 45, 60, and 90 minute after smoking. Regions for striatal structures were drawn on the coronal summed PET images guided with co-registered MRI. Binding potential, calculated as (striatal-cerebellar)/cerebellar activity, was measured under equilibrium condition at baseline and smoking session. Results: The mean decrease in binding potential of $[^{11}C]raclopride$ between the baseline and smoking in caudate head, anterior putamen and ventral striatum was 4.7%, 4.0% and 7.8%, respectively. This indicated the striatal dopamine release by smoking. Of these, the reduction in binding potential in the ventral striatum was significantly correlated with the cumulated plasma level of the nicotine (Spearman's rho=0.9, p=0.04). Conclusion: These data demonstrate that in vivo imaging with $[^{11}C]raclopride$ PET could measure nicotine-induced dopamine release in the human brain, which has a significant positive correlation with the amount or nicotine administered bt smoking.

• Korean Journal of Animal Reproduction
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• v.21 no.2
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• pp.167-176
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• 1997

This study was carried out to evaluate the potential for preselection of transgenic embryos prior to transfer into recipient animals. In these experiments, I used a 3.2 kb transgene which contained the neomycin resistance gene (neo) and lac Z gene driven by the $\beta$ actin promoter (iacZ Ineo). Oocytes were aspirated from abattoir ovaries, matured in TCM-199 supplemented with 10% fetal bovine serum (FBS), 5 ${\mu}\textrm{g}$/ml LH, 0.5 ${\mu}\textrm{g}$/ml FSH, 100 unit/ml penicillin, and 100 ${\mu}\textrm{g}$/ml streptomycin for 22 to 24 hrs then inseminated with a sperm suspension of 1 X 10$^6$ sperm/ml containing 5 ${\mu}\textrm{g}$/ml of heparin. At 18-20 hrs after insemination, cumulus cells were removed by vortexing and pronuclei of centrifuged zygotes microinjected with the lacZ/neo construct (3 ng/$\mu$l). All cultures were carried out in CR1aa with transfected BRL monolayers containing 3 mg/ml BSA, 20 $\mu$/ml NEM amino acids and 40 $\mu$I/ml BME amino acids. To identify the appropriate concentration of G418 for selection, non-microinjected zygotes were cultured in the presence of 0, 50, 100 and 200 $\mu$g/ml of G418. After 8 days of culture in these treatments, 44/145 (30.3%), 13/150 (8. 7%), 1/151 (0.7%) and 0/134 (0.0%) devel-oped to the blastocyst stage in 0, 50, 100 and 200 $\mu$g/ml of G418, respectively. A total of 1,127 zygotes were microinjected and placed into culture (without G418) and subsequently 710 (63.0%) cleaved. At 48 hrs post-injection, embryos ($\geq$2-cell) were randomly assigned to control (medium alone) or G418 (100 ${\mu}\textrm{g}$/ml) treatments. A control culture of 740 non-microinjected embryos from the same replicates of embryos were also placed into control medium. After 8 days in culture, 54/343 (15.7%) and 22/367 (6.0 %) of the microinjected embryos developed to the blastocyst stage in control and G418 media, respectively. A total of 151/740 (27.2%) of the non-microinjected embryos placed in the control medium developed to the blastocyst stage. The blastocysts in the control treatment had a mean of 70.7 ${\pm}$ 4.7 cells of which 23.1 ${\pm}$ 2.6 (32.7%) stained for $\beta$-Gal activity. B1astocysts in the G418 treatment had a mean of 48.8${\pm}$7.5 cells of which 40.3 ${\pm}$ 4.1 (82.6%) stained for $\beta$-Gal ac tivity (P<0.05). In the control treatment 26 of 30 (87.0%) blastocysts had some cells with $\beta$-Gal activity while all of the blastocysts in the G418 treatment had some cell with $\beta$-Gal ac tivity (P<0.05). However, ICM colonies in either control or G418 treatments were not expressed any epiblast cell except of trophetoderm celIs. The $\beta$-actin promoter/lacZ gene may not be e expression or silence expression in epiblast cells These results clearly show an enrichment of blastocysts expressing the transgene in the majority of their cells after culture in the presence of G418. The exogeneous gene was not express a and silence in ICM colonies especiallly epiblast cells except of trophectederm cells. Even though the higher rate cell number expressed of exogeneous gene in the G418 treatments, a total cell number was decrease significantly (P<0.05) of which might be also drop of the establishment of ES like-cell colonies and production of transgenic animals. However, futher studies need to determine the viability of these selected embryos and the avability of production of transgenic offspring.

• The Korean Journal of Air & Space Law and Policy
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• v.25 no.2
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• pp.139-162
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• 2010

In terms of the international air transport, the open skies policy implies freedom in the sky or opening the sky. In the normative respect, the open skies policy is a kind of open-door policy which gives various forms of traffic right to other countries, but on the other hand it is a policy of free competition in the international air transport. Since the Airline Deregulation Act of 1978, the United States has signed an open skies agreement with many countries, starting with the Netherlands, so that competitive large airlines can compete in the international air transport market where there exist a lot of business opportunities. South Korea now has an open skies agreement with more than 20 countries. The frequent flyer program (FFP) is part of a broad-based marketing alliance which has been used as an airfare strategy since the U.S. government's airline deregulation. The membership-based program is an incentive plan that provides mileage points to customers for using airline services and rewards customer loyalty in tangible forms based on their accumulated points. In its early stages, the frequent flyer program was focused on marketing efforts to attract customers, but now in the environment of intense competition among airlines, the program is used as an important strategic marketing tool for enhancing business performance. Therefore, airline companies agree that they need to identify customer needs in order to secure loyal customers more effectively. The outcomes from an airline's frequent flyer program can have a variety of effects on international competition. First, the airline can obtain a more dominant position in the air flight market by expanding its air route networks. Second, the availability of flight products for customers can be improved with an increase in flight frequency. Third, the airline can preferentially expand into new markets and thus gain advantages over its competitors. However, there are few empirical studies on the airline frequent flyer program. Accordingly, this study aims to explore the effects of the program on international competition, after reviewing the types of strategic alliance between airlines. Making strategic airline alliances is a worldwide trend resulting from the open skies policy. South Korea also needs to be making open skies agreements more realistic to promote the growth and competition of domestic airlines. The present study is about the performance of the airline frequent flyer program and international competition under the open skies policy. With a sample of five global alliance groups (Star, Oneworld, Wings, Qualiflyer and Skyteam), the study was attempted as an empirical study of the effects that the resource structures and levels of information technology held by airlines in each group have on the type of alliance, and one-way analysis of variance and regression analysis were used to test hypotheses. The findings of this study suggest that both large airline companies and small/medium-size airlines in an alliance group with global networks and organizations are able to achieve high performance and secure international competitiveness. Airline passengers earn mileage points by using non-flight services through an alliance network with hotels, car-rental services, duty-free shops, travel agents and more and show high interests in and preferences for related service benefits. Therefore, Korean airline companies should develop more aggressive marketing programs based on multilateral alliances with other services including hotels, as well as with other airlines.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.1
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• pp.61-71
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• 2015

Purpose : 3D Printers are used to create three-dimensional models based on blueprints. Based on this characteristic, it is feasible to develop a bolus that can minimize the air gap between skin and bolus in radiotherapy. This study aims to compare and analyze air gap and target dose at the branded 1 cm bolus with the developed customized bolus using 3D printers. Materials and Methods : RANDO phantom with a protruded tumor was used to procure images using CT simulator. CT DICOM file was transferred into the STL file, equivalent to 3D printers. Using this, customized bolus molding box (maintaining the 1 cm width) was created by processing 3D printers, and paraffin was melted to develop the customized bolus. The air gap of customized bolus and the branded 1 cm bolus was checked, and the differences in air gap was used to compare $D_{max}$, $D_{min}$, $D_{mean}$, $D_{95%}$ and $V_{95%}$ in treatment plan through Eclipse. Results : Customized bolus production period took about 3 days. The total volume of air gap was average $3.9cm^3$ at the customized bolus. And it was average $29.6cm^3$ at the branded 1 cm bolus. The customized bolus developed by the 3D printer was more useful in minimizing the air gap than the branded 1 cm bolus. In the 6 MV photon, at the customized bolus, $D_{max}$, $D_{min}$, $D_{mean}$, $D_{95%}$, $V_{95%}$ of GTV were 102.8%, 88.1%, 99.1%, 95.0%, 94.4% and the $D_{max}$, $D_{min}$, $D_{mean}$, $D_{95%}$, $V_{95%}$ of branded 1cm bolus were 101.4%, 92.0%, 98.2%, 95.2%, 95.7%, respectively. In the proton, at the customized bolus, $D_{max}$, $D_{min}$, $D_{mean}$, $D_{95%}$, $V_{95%}$ of GTV were 104.1%, 84.0%, 101.2%, 95.1%, 99.8% and the $D_{max}$, $D_{min}$, $D_{mean}$, $D_{95%}$, $V_{95%}$ of branded 1cm bolus were 104.8%, 87.9%, 101.5%, 94.9%, 99.9%, respectively. Thus, in treatment plan, there was no significant difference between the customized bolus and 1 cm bolus. However, the normal tissue nearby the GTV showed relatively lower radiation dose. Conclusion : The customized bolus developed by 3D printers was effective in minimizing the air gap, especially when it is used against the treatment area with irregular surface. However, the air gap between branded bolus and skin was not enough to cause a change in target dose. On the other hand, in the chest wall could confirm that dose decrease for small the air gap. Customized bolus production period took about 3 days and the development cost was quite expensive. Therefore, the commercialization of customized bolus developed by 3D printers requires low-cost 3D printer materials, adequate for the use of bolus.

• Journal of the Korean Society of Radiology
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• v.11 no.1
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• pp.27-35
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• 2017

The purpose of this study was to investigate the features of CsI:Tl and $Gd_2O_2S$ detectors with an indirect conversion method using phantom in the DR (digital radiography) system by obtaining images of thick chest phantom, medium thickness thigh phantom, and thin hand phantom and by analyzing the SNR and CNR. As a result of measuring the SNR and CNR according to the thickness change of the subject, the SNR and CNR were higher in CsI:Tl detector than in $Gd_2O_2S$ detector when the medium thickness thigh phantom and thin hand phantom were scanned. However, when the thick chest phantom was used, for the SNR at 80~125 kVp and the CNR at 80~110 kVp in the $Gd_2O_2S$ detector, the values were higher than those of CsI:Tl detector. The SNR and CNR both increased as the tube voltage increased. The SNR and CNR of CsI:Tl detector in the medium thickness thigh phantom increased at 40~50 kVp and decreased as the tube voltage increased. The SNR and CNR of $Gd_2O_2S$ detector increased at 40~60 kVp and decreased as the tube voltage increased. The SNR and CNR of CsI:Tl detctor in the thin hand phantom decreased at the low tube voltage and increased as the tube voltage increased, but they decreased again at 100~110 kVp, while the SNR and CNR of $Gd_2O_2S$ detector were found to decrease as the tube voltage increased. The MTF of CsI:Tl detector was 6.02~90.90% higher than that of $Gd_2O_2S$ detector at 0.5~3 lp/mm. The DQE of CsI:Tl detector was 66.67~233.33% higher than that of $Gd_2O_2S$ detector. In conclusion, although the values of CsI:Tl detector were higher than those of $Gd_2O_2S$ detector in the comparison of MTF and DQE, the cheaper $Gd_2O_2S$ detector had higher SNR and CNR than the expensive CsI:Tl detector at a certain tube voltage range in the thick check phantom. At chest X-ray, if the $Gd_2O_2S$ detector is used rather than the CsI:Tl detector, chest images with excellent quality can be obtained, which will be useful for examination. Moreover, price/performance should be considered when determining the detector type from the viewpoint of the user.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.49-61
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• 2014

Purpose: With the aging of the population, the attack rate of osteoporotic vertebral compression fracture is in the increasing trend, and percutaneous vertebroplasty (PVP) is the most commonly performed standardized treatment. Although there is a research report of the excellence of usefulness of the SPECT/CT examination in terns of the exact diagnosis before and after the procedure, the bone cement material used in the procedure influences the image quality by forming an artifact in the CT image. Therefore, the objective of the research lies on evaluating the effect the bone cement gives to a SPECT/CT image. Materials and Methods: The images were acquired by inserting a model cement to each cylinder, after setting the background (3.6 kBq/mL), hot cylinder (29.6 kBq/mL) and cold cylinder (water) to the NEMA-1994 phantom. It was reconstructed with Astonish (Iterative: 4 Subset: 16), and non attenuation correction (NAC), attenuation correction (AC+SC-) and attenuation and scatter correction (AC+SC+) were used for the CT correction method. The mean count by each correction method and the count change ratio by the existence of the cement material were compared and the contrast recovery coefficient (CRC) was obtained. Additionally, the bone/soft tissue ratio (B/S ratio) was obtained after measuring the mean count of the 4 places including the soft tissue(spine erector muscle) after dividing the vertebral body into fracture region, normal region and cement by selecting the 20 patients those have performed PVP from the 107 patients diagnosed of compression fracture. Results: The mean count by the existence of a cement material showed the rate of increase of 12.4%, 6.5%, 1.5% at the hot cylinder of the phantom by NAC, AC+SC- and AC+SC+ when cement existed, 75.2%, 85.4%, 102.9% at the cold cylinder, 13.6%, 18.2%, 9.1% at the background, 33.1%, 41.4%, 63.5% at the fracture region of the clinical image, 53.1%, 61.6%, 67.7% at the normal region and 10.0%, 4.7%, 3.6% at the soft tissue. Meanwhile, a relative count reduction could be verified at the cement adjacent part at the inside of the cylinder, and the phantom image on the lesion and the count increase ratio of the clinical image showed a contrary phase. CRC implying the contrast ratio and B/S ratio was improved in the order of NAC, AC+SC-, AC+SC+, and was constant without a big change in the cold cylinder of the phantom. AC+SC- for the quantitative count, and AC+SC+ for the contrast ratio was analyzed to be the highest. Conclusion: It is considered to be useful in a clinical diagnosis if the application of AC+SC+ that improves the contrast ratio is combined, as it increases the noise count of the soft tissue and the scatter region as well along with the effect of the bone cement in contrast to the fact that the use of AC+SC- in the spine SPECT/CT examination of a PVP performed patient drastically increases the image count and enables a high density of image of the lesion(fracture).

• The Korean Society of Law and Medicine
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• v.21 no.2
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• pp.105-162
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• 2020

In the pandemic of infectious disease, restrictions of individual liberty have been justified in the name of public health and public interest. In March 2020, the National Assembly of the Republic of Korea passed the revised bill of the 「Infectious Disease Control and Prevention Act.」 The revised bill newly established the legal basis for forced testing and disclosure of the information of confirmed cases, and also raised the penalties for violation of self-isolation and treatment refusal. This paper examines whether and how these individual liberty limiting clauses be justified, and if so on what ethical and philosophical grounds. The authors propose the theories of the philosophy of law related to the justifiability of liberty-limiting measures by the state and conceptualized the dual-aspect of applying the liberty-limiting principle to the infected patient. In COVID-19 pandemic crisis, the infected person became the 'Patient as Victim and Vector (PVV)' that posits itself on the overlapping area of 'harm to self' and 'harm to others.' In order to apply the liberty-limiting principle proposed by Joel Feinberg to a pandemic with uncertainties, it is necessary to extend the harm principle from 'harm' to 'risk'. Under the crisis with many uncertainties like COVID-19 pandemic, this shift from 'harm' to 'risk' justifies the state's preemptive limitation on individual liberty based on the precautionary principle. This, at the same time, raises concerns of overcriminalization, i.e., too much limitation of individual liberty without sufficient grounds. In this article, we aim to propose principles regarding how to balance between the precautionary principle for preemptive restrictions of liberty and the concerns of overcriminalization. Public health crisis such as the COVID-19 pandemic requires a population approach where the 'population' rather than an 'individual' works as a unit of analysis. We propose the second expansion of the harm principle to be applied to 'population' in order to deal with the public interest and public health. The new concept 'risk to population,' derived from the two arguments stated above, should be introduced to explain the public health crisis like COVID-19 pandemic. We theorize 'the extended harm principle' to include the 'risk to population' as a third liberty-limiting principle following 'harm to others' and 'harm to self.' Lastly, we examine whether the restriction of liberty of the revised 「Infectious Disease Control and Prevention Act」 can be justified under the extended harm principle. First, we conclude that forced isolation of the infected patient could be justified in a pandemic situation by satisfying the 'risk to the population.' Secondly, the forced examination of COVID-19 does not violate the extended harm principle either, based on the high infectivity of asymptomatic infected people to others. Thirdly, however, the provision of forced treatment can not be justified, not only under the traditional harm principle but also under the extended harm principle. Therefore it is necessary to include additional clauses in the provision in order to justify the punishment of treatment refusal even in a pandemic.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 1995.11a
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• pp.1-48
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• 1995

식생활은 인간 생활의 주체이고 먹는다는 것은 그 수단이다. 그중 중요한 하나의 명제는 인간이 놓여진 여러 환경에서 어떻게 건강을 유지하고 그 개체가 소유하고 있는 능력을 최대치까지 생리적으로 성장 발전시킴과 동시에 최대한 수명을 연장시키기 위한 식물 섭취방법을 마이크로 레벨까지 해명하는데 있다. 인간은 일생동안 엄청난 양의 음식물을 먹는다(70세 수명일 경우 200만 파운드 즉 체중의 1,400배). 그러나 먹기는 먹되 자신의 건강과 장수를 위하여 어떤 음식을 어떻게 선택하여 어떻게 먹어야 하는 문제가 매우 중요하다. 최근 우리나라도 국민 소득이 늘면서 식생활은 서구화 경향으로 기우는 듯하다. 공해를 비롯한 수입식품 등 여러 가지 문제점이 제기됨에 따라 자연식과 건강식을 주장하는 소리가 높이 일고 있다. 그중에는 축산 식품이 콜레스테롤 함량이 다른 식품에 비하여 높게 함유하고 있다는 것으로 심혈관질환의 주범인양 무차별 강조하는 나머지 육식공포 내지는 계란 등의 혐오감 마저 불러 일으키는 경향까지 있는 듯하다. 따라서 본논고에서는 축산식품중의 콜레스테롤 함량수준이 과연 성인병의 주범인지 아니면 다른 지방산과 관련해서 올바르게 평가하고 그 문제점과 대책을 개관해 보고 요약하면 다음과 같다. 1. 사람은 유사이래 본능적으로 주변의 식물이나 동물의 고기를 먹고 성장하여 자손을 증식시키고 어느 사이에 늙으면 죽음을 맞이 하는 싸이클을 반복하면서 기나긴 세월동안 진화를 하여 오늘날의 인간으로서의 자태를 이루었다. 유인원과 같은 인류의 선조들은 수렵을 통해 육식을 많이 하였을 것이므로 인간은 원래 육식동물이 아닐까? 구석기시대의 유물을 보면 많은 뼈가 출토되고 “얄타미라”나 “라스코” 동굴벽화가 선명하게 묘사되고 있다. 2. 우리나라 선조 승구족의 일파가 백두산을 비롯한 만주 송화강 유역에 유입되면서 수렵과 목축을 주요 식품획득의 수단으로 식품문화권을 형성하면서 남하하여 한반도 민족의 조상인 맥족(貊族)으로 맥적(貊炙)이라고 하는 요리(오늘날의 불고기)를 먹었다는 기록이 있다. 3. 인간의 수명을 1900년대로 거슬러 올라가서 뉴질랜드가 세계최장수국(호주는 2위)로서 평균수명은 남자 58세, 여자 69세인 반면 일본과 한국은 당시 남자 36세, 여자 37세이던 것이 일본은 1989년에 이르러 세계 최장수국으로 등장했으나 1990년 당시 뉴질랜드${\cdot}$호주 등은 목축 및 밀(小麥) 생산국가였기 때문이라는 것과 일본은 오늘날 합리적인 식생활 국가라는 것을 간과해서는 안된다. 4. 우리나라 10대 사망원인중 (1994년도) 뇌혈관질환이 1위, 교통사고 2위, 암이 3위 순위로서 연령별로는 10~30대의 불의의 사고(교통사고), 40~60대는 암, 70대 이상은 뇌혈관질환이 가장 많다. 구미${\cdot}$일 7개국 정상국가들은 심질환 사망이 가장 높다. 5. 식생활의 변화에 있어서 우리나라는 주식으로 섭취해 왔던 곡류는 70년 대비 94년에는 0.7배 감소된 반면 육류 5배, 계란 2.4배, 우유는 무려 29.3배 증가되었다. 식생활 패턴이 서구화 경향으로 바뀌는 것 같다. 6. 71년도 우리나라의 지질섭취량은 국민 1인당 1일 평균 13.1g에 섭취에너지의 5.7%수준이었으나 92년도에는 34.5g으로서 총에너지 섭취량의 16.6%에 달하고 총섭취 지방질중 동물성 섭취 비율은 47%를 차지 한다. 국민 평균 혈청콜레스테롤 농도는 80년에 비해 88년에는 11%가 증가되었고 80년에 210mg/dl 이상 되는 콜레스테롤 혈증인 사람의 비율이 5%에서 88년에는 23%로 크게 증가했다. 7. 세계 정상국가들의 단백질 즉 축산식품의 섭취는 우리나라보다 적게는 2배, 많게는 6~7배 더 섭취하고 90년도 우리나라의 지질섭취량은 일본의 1/3수준에 불과하다. 8. 콜레스테롤은 인체를 비롯한 모든 동물체에 필수적으로 분포하고 있는 것으로 체내 존재하고 있는 총량은 90~150g, 이중 혈청콜레스테롤은 4%(6g)를 차지하고 있음에도 불구하고 이 아주 적은 콜레스테롤에 일희일비(一喜一悲) 논쟁은 60~70년 끄러오고 있다. 9. 콜레스테롤의 생체내 기능으로서는 (1) 세포벽의 지지물질 (2) 신경세포 보호막물질 (3) 담즙산의 합성 (4) 비타민 D의 합성 (5) 임신시에 반듯이 필요한 분자 (6) 기타 여러 가지 기능을 수행하는 것으로 필수적인 물질이다. 10. 우리가 식이를 통해서 섭취 콜레스테롤을 550mg정도를 섭취한다고 하더라도 이 정도의 양은 배설 소모되는 양과 거의 맞먹는 양이다. 피부와 땀샘에서 소실되는 양만도 100~300mg에 달하기 때문에 미국농무성에서 섭취량을 300mg로 제한하는 것은 무의미하다. 11. 콜레스테롤 운반체로서의 지단백질은 그 밀도가 낮은 것으로부터 킬로미크론(chylomicron), 초저밀도 지단백질(VLDL), 저밀도 지단백질(LDL) 및 고밀도 지단백질(HDL)으로 나누는데 LDL은 혈청콜레스테롤 중 약 70%, HDL은 약20%를 함유한다. 12. 혈중 콜레스테롤 수준에 영향을 미치는 요인을 열거하여 보면 다음과 같다. 1) 음식을 통해서 섭취되는 콜레스테롤 중 단지 10~40%정도가 흡수되고, 체내에서 합성되는 콜레스테롤이 증가할수록 식이콜레스테롤은 실제 혈청콜레스테롤 수준에 거의 영향을 미치지 않으므로 식이중함량에 대하여 공포를 느끼고 기피할 필요가 없다. 2) 고도불포화지방산, 단가불포화지방산, 포화지방산의 비 즉 P/M/S의 비가 균형되도록 권장한다. 3) 동맥경화를 비롯한 성인병의 원인이 되는 혈전증에는 EPA의 양을 높여줌으로서 성인병을 예방할 수 있다. 4) 오메가6지방산 아라키도닉산과 오메가3지방산인 EPA로 유도되는 에이코사에노이드 또는 프로스타노이드는 오메가6와 3지방산을 전구체로 하여 생합성되는 중요한 생리활성 물질이다. 5) 사람은 일반적으로 20세에서 60세까지 나이를 먹어감에 따라 혈중 콜레스테롤 수준이 증가하고 60세 이후부터는 일정한 수준을 유지하며 심장보호성 HDL-콜레스테롤은 감소하는 반면에 죽상경화성 LDL콜레스테롤은 증가한다. 6) 높은 HDL콜레스테롤 수준이 심장병 발생 위험요인을 감소시키는 기능을 갖고 있기 때문에 좋은 HDL이라 부르고, LDL은 나쁜 콜레스테롤이라 부르기도 하는데, 이것은 유전적 요인보다도 환경적 요인이 보다 큰 영향을 미친다. 7) 이것은 생활 형태와 영양섭취상태를 포함해서 개인적 생활패턴에 영향을 받는다. 8) 많은 실험에서 혈중 콜레스테롤 상승은 노년의 가령(加齡)에 적응하기 위한 자연적 또는 생리적인 세포의 생화학적이고 대사적인 기능을 위해 필수적일 수 있다는 것을 간과해서는 안될 것이다. 이 점으로 미루어 노년의 여성들을 위한 콜레스테롤 농도를 200mg/dl이 가장 알맞은 양이 아닌 듯하다. 9) 스트레스는 두가지 모양으로 유발되는데 해로은 스트레스(negative), 이로운 스트레스(positive)로서 긴장완화는 혈중 콜레스테롤 농도를 10% 떨어진다. 10) 자주 운동을 하는 사람들은 혈중 HDL콜레스테롤치가 운동을 하지 않는 사람보다 높다. 육체적인 운동의 정도와 혈중 HDL콜레스테롤 농도와는 정비례한다. 11) 흡연은 지방을 흡착시키므로 혈전증의 원이이 되며 혈관속의 HDL농도를 감소시킨다. 12) 에너지의 과잉섭취에 의한 체중 증가느 일반적으로 지단백질대사에 영향을 미치고, 간에서는 콜레스테롤 과잉 생산과 더불어 VLDL콜레스테롤의 LDL콜레스테롤 혈증을 나타냄으로 운동과 더불어 비만이 되지 않도록 하여야 한다. 13. 콜레스테롤 함량에 대한 조절기술 1) 식품의 우열을 평가할 때 단순히 동물성 또는 식물성 식품으로 분류해서 총괄적으로 논한다는 것은 지양되어야 한다. 이것은 그 식품에 함유하고 있는 지방산의 종류에 따라서 다르기 때문이다. 2) 인체의 원할한 기능 유지를 위해서는 P /M /S비율 뿐만 아니라 섭취 지방질의 오메가6 /오메가3계 지방산의 비율이 모두 적절한 범위에 있어야 하며 한두가지 지방산만이 과량일 때는 또 다른 불균형을 일으킬 수 있다는 점을 알아야 한다. 3) 닭고기는 오메가6지방산 함량을 높이기 위하여 사료중에 등푸른 생선이나 어분이나 어유를 첨가하여 닭고기는 첨가수준에 따라 증가됨을 알 수 있다. 4) 오늘날 계란내의 지방산 조성을 변화시켜 난황내의 오메가 3계열 지방산 함량을 증가시킨 계란의 개발이 활발해졌다. 14. 계란 콜레스테롤에 대한 소비자들의 부정적 인식을 불식시키고자 계란의 클레스테롤 함량을 낮추는 과제가 등장하면서 그 기술개발이 여러모로 시도되고 있으나 아직 실용 단계에 이르지 못했다. 15. 계란의 콜레스테롤 문제에 대한 대책으로서 난황의 크기를 감소시키는 방법에 대한 연구도 필요하다. 16. 계란 중 콜레스테롤 함량 분석치는 표현 방식에 따라서 소비자들을 혼란시킬 가능성이 있다. 또한 과거에는 비색법으로 분석했으나 오늘날은 효소법으로 분석하면 분석치에 상당한 차이가 있다. 17. 소비자의 요구를 만족시키고 버터 소비를 촉진시키기 위해 콜레스테롤을 감소시키는 물리적${\cdot}$생물학적 방식이 제안되어 있으나 현장적용이 가능한 것은 아직 없다. 18. 우리나라에서 이미 시판되고 있는 DHA우유가 선보였고 무콜레스테롤 버터의 경우 트란스(trans)형 지방산에 관해서는 논란의 여지가 많을 것이다. 끝으로 국가 목표의 하나는 복지사회 건설에 있고 복지국가 실현에는 국민 기본 욕망의 하나인 식생활 합리화가 선행되어야 한다. 소득이 늘고 국가가 발전해감에 따라 영양식${\cdot}$건강식 및 기호식을 추구하게 됨을 매우 당연한 추세라 하겠다. 우리의 식생활이 날로 향상되어 지난날의 당질 위주에서 점차 축산물쪽으로 질적 개선이 이루어진다는 것은 고무적임에 틀림없다. 이 축산물을 통한 풍요로운 식의 문화를 창출하면서 건강과 장수 그리고 후손에 이르기까지 번영하고 국가 경쟁력 강화에 심혈을 기우려야 할 때이다.