• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.4
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• pp.265-273
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• 2001

The sea urchin has been used as sea food in many countries. This species has also been an important organism of embryological studies for more than a century. In recent years, sea urchin embryos are being used as testing materials for toxicity of pollutants and toxins. Usefulness of sea urchin embryos as experimental models comes from the easiness in obtaining sea urchin samples and a lot of gametes, in rearing embryos in the laboratory, in observing the cellular movement and organ formation during the embryogenesis and in manipulating blastomeres and genetic maferials. The sea urchin in itself is a key organism for the understanding of deuterostome evolution from the protostomes and of indirect development of marine invertebrates which undergo the planktotrophic larval stage. A fertilized sea urchin egg goes through rapid cleavage and becomes a 60 cell embryo 7hr after fertilization. It then develops into a morula, a blastula, a gastrula and finally a pluteus larva approximately 70 hr after fertilization. At the 60 cell stage, the embryo comprises of five territories that express territory-speciflc genes and later form different organs. Micromeres at the vegetal pole ingress into the blastoceol and become the primary mesenchyme cells(PMCs). PMCs express genes involved in skeletogenesis such as SM30, SM37, SM50, PM27, msp130. Among the genes, SM37 and SM50 are considered to be members of a gene family which is characterized by early blastula expression, Glycine-Proline-Glutamine rich repeat structures and spicule matrix forming basic proteins. Genetic studies on the sea urchin embryos help understand the molecular basis of indirect development of marine invertebrates and also of the biomineralization common to the animal kingdom.

• Journal of the Korean Geotechnical Society
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• v.28 no.7
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• pp.41-53
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• 2012

During rainfall period, to identify the characteristics of the infiltration of moisture, electrical resistivity monitering survey was carried out to weathered zone. Four regions of geophysical exploration areas with different rock types, four regions were selected. An area consists of mafic granite and three areas are composed of sedimentary rocks (Sandstone, Shale, Unconsolidated Mudstone). Survey was conducted from June (rainy season) to November (dry season), and during the period the change in resistivity was observed. According to the result of monitoring exploration on Geumjeong and Jinju areas, for the estimation of the standard rainfall, it is necessary to estimate the effects of the antecedent rainfall during the rainy season based on the overall rainfall from June till October and also necessary to consider this for the estimation of the half period. Also, the vertical distribution of the low resistivity anomaly zone does not show that the infiltration of moisture does not occur uniformly from the surface of the ground to the lower ground but shows that it occurs along the relaxed gap of the crack or soil stratum of the weathering zone. In Pohang area, the type of moisture infiltration is different from that of the granite or sedimentary rock. Since, after the rainfall, the rate of infiltration to the lower ground is high and the period of cultivation to the lower bedrock aquifer is short, it has similar effect to that of the antecedent rainfall applied for the estimation of the standard rainfall being presently used. In Danyang, due to the degree of water content of the ground, the duration period of the low resistivity anomaly zone observed in the lower ground of the place where clastic sedimentary rock is distributed is similar to that in Pohang area. The degree of lateral water diffusion at the time of localized heavy rain is the same as that of the sedimentary rock in Jinju. According to the above analysis results, in Danyang area, the period when the antecedent rainfall has its influence is estimated as three weeks or so.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.2
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• pp.289-295
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• 2014

Purpose : Cone Beam Computed Tomography(CBCT) in Image Guided Radiation Therapy(IGRT), Set-up error can be reduced but exposure dose of the patient due to CBCT will increase. Through this study, we are to evaluate by making a scenario with the implementation period of CBCT as every other day. Materials and Methods : Of prostate cancer patients, 9 patients who got a Intensity Modulated Radiation Therapy(IMRT) with CBCT in IGRT were analyzed. Based on values corrected by analyzing set-up error by using CBCT every day during actual treatment, we created a scenario that conducts CBCT every other day. After applying set-up error values of the day not performing CBCT in the scenario to the treatment planning system(Pinnacle 9.2, Philips, USA) by moving them from the treatment iso-center during actual treatment, we established re-treatment plan under the same conditions as actual treatment. Based on this, the dose distribution of normal organs and Planning Target Volume(PTV) was compared and analyzed. Results : In the scenario that performs CBCT every other day based on set-up error values when conducting CBCT every day, average X-axis : $0.2{\pm}0.73mm$, Y-axis : $0.1{\pm}0.58mm$, Z-axis : $-1.3{\pm}1.17mm$ difference was shown. This was applied to the treatment planning to establish re-treatment plan and dose distribution was evaluated and as a result, Dmean : -0.17 Gy, D99% : -0.71 Gy of PTV difference was shown in comparison with the result obtained when carrying out CBCT every day. As for normal organs, V66 : 1.55% of rectal wall, V66 : -0.76% of bladder difference was shown. Conclusion : In case of a CBCT perform every other day could reduce exposure dose and additional treatment time. And it is thought to be able to consider the application depending on the condition of the patient because the difference in the dose distribution of normal organs, PTV is not large.

• The korean journal of orthodontics
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• v.40 no.6
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• pp.398-410
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• 2010

Objective: The purpose of this study was to investigate the changes in dentofacial morphology of non-orthodontically treated female patients with TMJ disk displacement. Methods: The sample consisted of 25 Korean female patients with bilateral TMJ disk displacement who visited the Department of Orthodontics, Seoul National University Dental Hospital from 1996 to 2006. Disk displacements were diagnosed using the magnetic resonance imaging (MRI) of both TMJs. Baseline (T1) and follow-up (T2) lateral cephalograms were analyzed. The mean age of samples at T1 was $18.1{\pm}3.5$ years (range 14.2 - 25.8 years) and at T2, $21.1{\pm}3.5$ years (range 16.2 - 28.0 years). The mean observation period was $3.0{\pm}1.9$ years. Descriptive statistics for each variable were calculated at baseline (T1) and follow-up (T2) stages, and during the observation period (T2-T1). Results: Skeletal changes were found in 64% of the non-orthodontically treated female patients with TMJ disk displacement during the observation period. The L1 to Mandibular plane distance (mm) increased significantly by 0.8 mm (p < 0.01). But there were no significant differences in the other dental relationship variables (overjet, overbite, U1 to palatal plane) during the observation period. Most patients with skeletal changes showed a backward rotation of the mandible. The ratio of the rotation was a decrease of SNB by $0.43^{\circ}$ for every $1^{\circ}$ increase of FMA (Spearman rho = -0.660, P < 0.01). A few patients showed a distal shift of the mandible without rotation or significant changes in the vertical dimension. Conclusions: During observation periods without orthodontic treatment, non-growing patients with TMJ disk displacement showed dentoskeletal changes, mainly backward rotation of the mandible.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.316-326
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• 2014

Determination of the late marginal heading date (LMHD), which would allow estimation of the late marginal seeding date and the late marginal transplanting date, would help identification of potential double cropping areas and, as a result, establishment of cropping systems. The objective of this study was to determine the LMHD at 51 sites in Korea. For these sites, weather data were obtained from 1971 to 2000 and from 1981 to 2010, which represent past and current normal climate conditions, respectively. To examine crop productivity on the LMHD, climatic yield potential (CYP) was determined to represent the potential yield under a given climate condition. The LMHD was calculated using accumulated temperature for 40 days with threshold values of $760^{\circ}C$, $800^{\circ}C$, $840^{\circ}C$ and $880^{\circ}C$. The value of CYP on a given LMHD was determined using mean temperature and sunshine duration for 40 days from the LMHD. The value of CYP on the LMHD was divided by the maximum value of CYP (CYPmax) in a season to represent the relative yield on the LMHD compared with the potential yield in the season. Our results indicated that the LMHD was delayed at most sites under current normal conditions compared with past conditions. Spatial variation of the LMHD differed by the threshold temperature. Overall, the minimum value of CYP/CYPmax was 81.8% under all of given conditions. In most cases, the value of CYP/CYPmax was >90%, which suggested that yield could be comparable to the potential yield even though heading would have occurred on the LMHD. When the LMHD could be scheduled later without considerable reduction in yield, the late marginal transplanting date could also be delayed accordingly, which would facilitate doublecropping in many areas in Korea. Yield could be affected by sudden change of temperature during a grain filling period. Yet, CYP was calculated using mean temperature and sunshine duration for 40 days after heading. Thus, the value of CYP/CYPmax may not represent actual yield potential due to change of the LMHD, which suggested that further study would be merited to take into account the effect of weather events during grain filling periods on yield using crop growth model and field experiments.

• Analytical Science and Technology
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• v.16 no.4
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• pp.292-298
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• 2003

In this study, the photooxidation and ozonation of humic acid (HA) in aqueous solution were conducted and the treated HA samples at different reaction time were analyzed using ultrafiltration techniques to evaluate the change of their molecular size distributions with its DOC removal. Molecular size distribution of untreated HA showed 41.5% in higher molecular size fractions (>30,000 daltons) and 15.2% in much smaller molecular size fraction (<500 daltons). As UV irradiation time was increased, it was observed that the degradation of the large molecules of the fraction of >30,000 daltons into much smaller molecules was increased. In UV system, the HA molecules of the fraction of <500 daltons became significantly more and its percentage was increased from 35.3% (UV only irradiation) to 58.9% ($UV/TiO_2$) and 87.8% ($UV/H_2O_2$) in the presence of the photocatalysis. Otherwise, ozonation of HA produced mainly the fraction of medium molecular size ranging from 3,000 to 30,000 daltons with much lower portion (<~7%) in the fraction of <500 daltons. In ozone only system, the fraction of 30,000~10,000 daltons occupied in 41.5% at 60 min of ozonation time. In $O_3/H_2O_2$ system, the fraction of 30,000~10,000 daltons and 10,000~3,000 daltons occupied in 38.9% and 36.2% respectively. Based on these results, we suggested applicable treatment process which could be combined with $UV/H_2O_2$, $UV/TiO_2$ and $O_3$, $O_3/H_2O_2$ system for more effective removal of humic acid in water treatment.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.1
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• pp.47-56
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• 2018

Providing high-quality meteorological observation data at sites that represent actual farming environments is essential for useful agrometeorological services. The Automated Agricultural Observing System (AAOS) of the Korean Meteorological Administration, however, has been deployed on lawns rather than actual farm land. In this study, we show the inaccuracies that arise in AAOS data by analyzing temporal and vertical variation and by comparing them with data recorded by the National Center for AgroMeteorology (NCAM) tower that is located at an actual farming site near the AAOS tower. The analyzed data were gathered in August and October (before and after harvest time, respectively). Observed air temperature and water vapor pressure were lower at AAOS than at NCAM tower before and after harvest time. Observed reflected shortwave radiation tended to be higher at AAOS than at NCAM tower. Soil variables showed bigger differences than meteorological observation variables. In August, observed soil temperature was lower at NCAM tower than at AAOS with smaller diurnal changes due to irrigation. The soil moisture observed at NCAM tower continuously maintained its saturation state, while the one at AAOS showed a decreasing trend, following an increase after rainfall. The trend changed in October. Observed soil temperature at NCAM showed similar daily means with higher diurnal changes than at AAOS. The soil moisture observed at NCAM was continuously higher, but both AAOS and NCAM showed similar trends. The above results indicate that the data gathered at the AAOS are inaccurate, and that ground surface cover and farming activities evoke considerable differences within the respective meteorological and soil environments. We propose to shift the equipment from lawn areas to actual farming sites such as rice paddies, farms and orchards, so that the gathered data are representative of the actual agrometeorological observations.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.56-62
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• 2015

Various pretreatment methods were evaluated to prevent tissue softening of heated onion. Changes in onion tissue firmness during heating were explained by 3-mechanism model consisting of texture hardening at low temperature ($60-80^{\circ}C$) and substrate softening at high temperature. Preheating of onion in a $Ca^{2+}$-containing solution significantly improved its texture after high-temperature heating. The improvement of firmness by preheating at low temperature was related to the formation of strong cross-linking between carboxyl groups and $Ca^{2+}$ by the action of pectin methylesterase in onion. The highest firmness was obtained by pre-heating at $70^{\circ}C$ for 120 min in 0.5% calcium solution. This result was supported by chemical analysis showing that the amount of bound calcium was the highest at $70^{\circ}C$. Further investigation should be carried out to establish the optimal conditions to prevent the softening of various vegetables.

• Journal of Intelligence and Information Systems
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• v.23 no.1
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• pp.127-141
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• 2017

Advances in Internet technologies and the proliferation of mobile devices enabled consumers to approach a wide range of goods and services, while causing an adverse effect that they have hard time reaching their congenial items even if they devote much time to searching for them. Accordingly, businesses are using the recommender systems to provide tools for consumers to find the desired items more easily. Association Rule Mining (ARM) technology is advantageous to recommender systems in that ARM provides intuitive form of a rule with interestingness measures (support, confidence, and lift) describing the relationship between items. Given an item, its relevant items can be distinguished with the help of the measures that show the strength of relationship between items. Based on the strength, the most pertinent items can be chosen among other items and exposed to a given item's web page. However, the diversity of the measures may confuse which items are more recommendable. Given two rules, for example, one rule's support and confidence may not be concurrently superior to the other rule's. Such discrepancy of the measures in distinguishing one rule's superiority from other rules may cause difficulty in selecting proper items for recommendation. In addition, in an online environment where a web page or mobile screen can provide a limited number of recommendations that attract consumer interest, the prudent selection of items to be included in the list of recommendations is very important. The exposure of items of little interest may lead consumers to ignore the recommendations. Then, such consumers will possibly not pay attention to other forms of marketing activities. Therefore, the measures should be aligned with the probability of consumer's acceptance of recommendations. For this reason, this study proposes a model-based approach to combine those measures into one unified measure that can consistently determine the ranking of recommended items. A regression model was designed to describe how well the measures (independent variables; i.e., support, confidence, and lift) explain consumer's acceptance of recommendations (dependent variables, hit rate of recommended items). The model is intuitive to understand and easy to use in that the equation consists of the commonly used measures for ARM and can be used in the estimation of hit rates. The experiment using transaction data from one of the Korea's largest online shopping malls was conducted to show that the proposed model can improve the hit rates of recommendations. From the top of the list to 13th place, recommended items in the higher rakings from the proposed model show the higher hit rates than those from the competitive model's. The result shows that the proposed model's performance is superior to the competitive model's in online recommendation environment. In a web page, consumers are provided around ten recommendations with which the proposed model outperforms. Moreover, a mobile device cannot expose many items simultaneously due to its limited screen size. Therefore, the result shows that the newly devised recommendation technique is suitable for the mobile recommender systems. While this study has been conducted to cover the cross-selling in online shopping malls that handle merchandise, the proposed method can be expected to be applied in various situations under which association rules apply. For example, this model can be applied to medical diagnostic systems that predict candidate diseases from a patient's symptoms. To increase the efficiency of the model, additional variables will need to be considered for the elaboration of the model in future studies. For example, price can be a good candidate for an explanatory variable because it has a major impact on consumer purchase decisions. If the prices of recommended items are much higher than the items in which a consumer is interested, the consumer may hesitate to accept the recommendations.

• Strategy21
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• s.31
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• pp.251-293
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• 2013

해적은 공해상 해상안전을 위협 한다는 점에서 '인류공동의 적'으로 규정되어 모든 국가가 이를 규제할 수 있는 보편적 관할권이 행사되는 범죄이다. 한국을 포함한 아시아 지역 국가들은 말라카해협 통항에 관해 깊은 이해관계를 갖고 있어 해적 소탕에 대한 의지가 강한 편이다. 이러한 의지는 2006년 '아시아해적퇴치정보공유센터(ReCAAP ISO)'의 창설에 밑거름이 되었으며, 아시아 지역에서 해적이 출현하면 동 센터를 통해 17개국 회원국으로 즉시 통보되고, 주변국의 해경과 해군이 유기적인 작전을 통해 해적을 효율적으로 퇴치하고 있는 모범사례다. 그러나 2009년 소말리아 내란에 따른 무정부 상태가 지속되면서 소말리아 및 아덴만에서의 해적활동이 극성을 부리기 시작했으며, 선박납치 행위가 급증하자 세계 각국에서 함정과 항공기를 파견하여 해적퇴치 활동을 전개하고 있으나 근절되지 않을 뿐만 아니라 해적의 활동해역이 확대되고 있다. 이러한 배경 하에 시작된 본 연구는 연구결과를 중심으로 다음과 같은 대응 방안을 제시한다. 첫째, 소말리아 해적의 근본원인은 국가의 붕괴에서 비롯된 치안부재와 열악한 경제사정 등 내부적인 요인이 크기 때문에 다국적 해군 활동으로 인한 근본적인 해적퇴치에는 한계가 있다. 따라서 국제적인 차원에서 '지역협력협정'체결은 물론, 소말리아 국가재건을 위한 노력이 함께 이루어지는 종합적인 대책이 필요하다. 그러나 보다 더 근본적인 해결책은 유엔차원에서 빠른 시간 내에 소말리아가 정치적 안정을 유지할 수 있도록 정치적 차원에서의 지원이 필요하며, 해적과 테러리스트가 연계됨으로써 국제문제로 확대되지 않도록 하는 노력도 병행되어야 한다. 둘째, 해적문제는 특정국가에만 해당되는 것이 아니라 초국가적인 문제임을 감안하여 유엔안전보장이사회 결의 제1851호에서 '지역 센터' 설립을 권고하고 있는 것처럼 2006년 아시아 국가들이 설치한 ReCAAP ISO와 같은 형태의 지역국가 간 협력기구 또는 유엔 차원의 해적 전담기구를 설치하여 국제사회 공조 하에 해적에 대처하는 방안을 추진하는 것이 필요하다. 셋째, 최근 발생하고 있는 해적행위는 주로 항구 등 내수, 영해 등 연안국의 관할권이 행사되는 지역에서 발생하고 있어 유엔해양법상의 규정은 이러한 '해적' 퇴치에 더 이상 효율적이지 못하다. 국제사회는 이러한 문제점을 인식하여 국제해사기구 (IMO) 등 국제기구를 통해 영해내의 해적 처벌을 위해 최선의 노력을 기울이고 있다. 향후 궁극적으로는 유엔해양법협약의 개정을 통해 법적인 문제점이 개선되어야 한다. 넷째, 전술적인 측면에서도 지상에 기지를 두고 있는 해적들의 지도부가 그 동안 쌓아 놓은 네트워크를 이용하여 다국적 해군에 대한 정보를 수집하고 대응방안을 강구함으로써 나름대로의 생존전략을 구사할 것으로 예상된다. 특히, 선박을 납치한 후 소말리아 연안으로 이동하면서 해군함정과 대치하는 과정에서 해적들이 살상을 당하는 사례가 증가함에 따라 지금까지는 피랍된 선박의 선원을 단순히 해적활동에 참여시키거나, 항해지원을 위한 목적 등으로만 활용했는데, 앞으로는 해적들의 인명피해를 최소화하기 위해서라도 선원들을 방패막이로 활용할 가능성이 더욱 높아질 것으로 예상된다. 따라서 참가하는 해군함정 또는 부대간 해적들의 활동 관련 정보를 공유하는 등 사전에 정보를 획득하기 위한 협력을 강화해야 한다. 다섯째, 한국군함이 삼호주얼리호를 납치했던 소말리아 해적을 한국까지 대리고 와서 처벌하는 것은 불합리하고, 많은 문제점을 야기할 수 있기 때문에 향후 해적처벌을 위한 국제사법기구의 설치가 요구된다. 회원국 분담금으로 운영되는 유엔에 산하기관을 설치하여 소말리아 인접국에서 해결하도록 적극적인 노력을 경주할 필요가 있다. 마지막으로, 선박회사에서도 자국 선박이 위험구역으로 지정된 해역을 항해할 경우를 대비해서 선박자동식별 시스템 구축을 확대하고, 해적이 선박에 승선했을 경우를 대비해서 안전구역(citadel)을 설치하여 선원의 안전을 확보하는 등의 대책이 필요하다. 본 연구를 통해 해양안보는 어느 특정국가에게만 주어진 것이 아니며, 해적행위도 특정 국가의 선박을 대상으로 하는 것이 아니므로 각국 정부간 공동의 협력과 국제사회의 공조가 반드시 실현될 때 해적의 위협으로부터 선박의 안전과 국제사회의 평화가 실현될 수 있다는 것을 강조하고자 한다.