• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.4
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• pp.347-357
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• 2003

This paper describes on the suppression of sea clutter on marine radar display using a cell-averaging CFAR(constant false alarm rate) technique, and on the analysis of radar echo signal data in relation to the estimation of ARPA functions and the detection of the shadow effect in clutter returns. The echo signal was measured using a X -band radar, that is located on the Pukyong National University, with a horizontal beamwidth of $$3.9^{\circ}$$, a vertical beamwidth of $20^{\circ}$, pulsewidth of $0.8 {\mu}s$ and a transmitted peak power of 4 ㎾ The suppression performance of sea clutter was investigated for the probability of false alarm between $l0-^0.25;and; 10^-1.0$. Also the performance of cell averaging CFAR was compared with that of ideal fixed threshold. The motion vectors and trajectory of ships was extracted and the shadow effect in clutter returns was analyzed. The results obtained are summarized as follows；1. The ARPA plotting results and motion vectors for acquired targets extracted by analyzing the echo signal data were displayed on the PC based radar system and the continuous trajectory of ships was tracked in real time. 2. To suppress the sea clutter under noisy environment, a cell averaging CFAR processor having total CFAR window of 47 samples(20+20 reference cells, 3+3 guard cells and the cell under test) was designed. On a particular data set acquired at Suyong Man, Busan, Korea, when the probability of false alarm applied to the designed cell averaging CFAR processor was 10$^{-0}$.75/ the suppression performance of radar clutter was significantly improved. The results obtained suggest that the designed cell averaging CFAR processor was very effective in uniform clutter environments. 3. It is concluded that the cell averaging CF AR may be able to give a considerable improvement in suppression performance of uniform sea clutter compared to the ideal fixed threshold. 4. The effective height of target, that was estimated by analyzing the shadow effect in clutter returns for a number of range bins behind the target as seen from the radar antenna, was approximately 1.2 m and the information for this height can be used to extract the shape parameter of tracked target..

• Clinical and Experimental Reproductive Medicine
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• v.15 no.2
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• pp.103-117
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• 1988

Ovulation induction was done with 3 different regimens as clomid combined with HMG, HMG only, and FSH combined with HMG in 28 menstrual cycles for IVF-ET and GIFT program. The appearance of endogenous LH surge, estradiol plateau, atypical LH surge, and time from initiation to peak of LH surge in serum and urine were observed and compared in 3 groups. 1. The estradiol concentration of serum LH surge day was similar in three groups but 1st group (Clomiphene Citrate+Sequential HMG) was slightly higher at $1924.0{\pm}865.1\;pg/ml$. In regards to the existence of serum estradiol plateau, 3rd group (FSH+Sequential HMG) was highest at 60%, and 1st group and 2nd group (HMG only) were similar at 33% and 44% respectively. 2. The number of ovarian of ovarian follicle which was more than 18mm in diameter was $4.1{\pm}2.0$, $4.2{\pm}2.1$ respectibely for 2nd group and 3rd group. Although the numbers were slightly higher thean 1st group for each ovarian follicle, serum estradiol value per follicle was higher for 1st group at $583.0{\pm}261.2pg/ml$. 3. When measuring the urine LH surge according to Hi-Gonavi and according to the standard set by three different types of surge, simultameous satisfaction for 1st group, 2nd group, 3rd group was two cases, five cases, four cases respectively at 40%, and the remained cases were composed of numorous type combination which satisfied the two definition, simultaneously in this study, the LH surge starting time was determined only in the cases tow combination were satisfied simultaneously at first, but there are something to study more. In one case of the 3rd group. 4. The concentration of LH surge start in urine and serum of 2nd group was highest at306. $0{\pm}287.2IU/l$ and $34.0{\pm}9.9mIU/ml$ and 1st group was low at $116.6{\pm}66.1IU/l$ and 7.4mIU/ml. The urine and serum value of LH was highest at $1644.4{\pm}988.8IU/l$, $65.9{\pm}15.0mIU/ml$ for 2nd group, 1st group was low at urine, and 3rd group was low of serum. With pregnancy established, the LH concentration of urine was relatively high but on the contrary the LH concentration of serum was low compared to urine concentration. 5. Time from LH surge start to the maximun of urine and serum value was highest at 15. $7{\pm}9.1$ hrs and $10.8{\pm}4.9$ hrs for 1st group and 3rd group. With pregnancy established, time was shortened for urine but on the contrary serum showed an increase in time. 6. The concentration of LH which increases with time on urine was highest at 2nd group ($194.6{\pm}76.8\;IU/hour$). The lowest increase for serum was at 3rd group (2.1mIU/hour). With pregnancy established, urine showed more increase than control group ($266.5{\pm}47.4\;IU/hour$) and for serum there was similar increase ($3.4{\pm}0.8\;mIU/hour$). 7. There were two examples of non-typical surge from 1st group and 3rd group each. Among these three cases showed a reestablishment of LH surge after 10-24 hours. 8. Endogenous spontaneous Lh surge occurs once for each 2nd group and 3rd group.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2000.11a
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• pp.3-4
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• 2000

Many researchers are interested in the synthesis and characterization of carbon nitride and diamond-like carbon (DLq because they show excellent mechanical properties such as low friction and high wear resistance and excellent electrical properties such as controllable electical resistivity and good field electron emission. We have deposited amorphous carbon nitride (a-C:N) thin films and DLC thin films by shielded arc ion plating (SAIP) and evaluated the structural and tribological properties. The application of appropriate negative bias on substrates is effective to increase the film hardness and wear resistance. This paper reports on the deposition and tribological OLC films in relation to the substrate bias voltage (Vs). films are compared with those of the OLC films. A high purity sintered graphite target was mounted on a cathode as a carbon source. Nitrogen or argon was introduced into a deposition chamber through each mass flow controller. After the initiation of an arc plasma at 60 A and 1 Pa, the target surface was heated and evaporated by the plasma. Carbon atoms and clusters evaporated from the target were ionized partially and reacted with activated nitrogen species, and a carbon nitride film was deposited onto a Si (100) substrate when we used nitrogen as a reactant gas. The surface of the growing film also reacted with activated nitrogen species. Carbon macropartic1es (0.1 -100 maicro-m) evaporated from the target at the same time were not ionized and did not react fully with nitrogen species. These macroparticles interfered with the formation of the carbon nitride film. Therefore we set a shielding plate made of stainless steel between the target and the substrate to trap the macropartic1es. This shielding method is very effective to prepare smooth a-CN films. We, therefore, call this method "shielded arc ion plating (SAIP)". For the deposition of DLC films we used argon instead of nitrogen. Films of about 150 nm in thickness were deposited onto Si substrates. Their structures, chemical compositions and chemical bonding states were analyzed by using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and infrared spectroscopy. Hardness of the films was measured with a nanointender interfaced with an atomic force microscope (AFM). A Berkovich-type diamond tip whose radius was less than 100 nm was used for the measurement. A force-displacement curve of each film was measured at a peak load force of 250 maicro-N. Load, hold and unload times for each indentation were 2.5, 0 and 2.5 s, respectively. Hardness of each film was determined from five force-displacement curves. Wear resistance of the films was analyzed as follows. First, each film surface was scanned with the diamond tip at a constant load force of 20 maicro-N. The tip scanning was repeated 30 times in a 1 urn-square region with 512 lines at a scanning rate of 2 um/ s. After this tip-scanning, the film surface was observed in the AFM mode at a constant force of 5 maicro-N with the same Berkovich-type tip. The hardness of a-CN films was less dependent on Vs. The hardness of the film deposited at Vs=O V in a nitrogen plasma was about 10 GPa and almost similar to that of Si. It slightly increased to 12 - 15 GPa when a bias voltage of -100 - -500 V was applied to the substrate with showing its maximum at Vs=-300 V. The film deposited at Vs=O V was least wear resistant which was consistent with its lowest hardness. The biased films became more wear resistant. Particularly the film deposited at Vs=-300 V showed remarkable wear resistance. Its wear depth was too shallow to be measured with AFM. On the other hand, the DLC film, deposited at Vs=-l00 V in an argon plasma, whose hardness was 35 GPa was obviously worn under the same wear test conditions. The a-C:N films show higher wear resistance than DLC films and are useful for wear resistant coatings on various mechanical and electronic parts.nic parts.

• 한국해양학회지
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• v.23 no.2
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• pp.70-75
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• 1988

In order to set up a predictive model for an effective spat collection of ark shells, Anadara broughtonii, the survival rate and the time required for each developmental stage of planktonic larvae were investigated during the period from July 1 to October 30 in 1974, in one of the main ark shell seed collection areas, Chinhae Bay, in the southern part of Korea. The advent of D-shaped larvae ca. $94.3{\times}72.7{\mu}m$ long had three peaks during the surveyed period: August 25, August 31 and September 9, umbo-shaped larvae ca. $141.6{\times}108.4{\mu}m$ and full grown larvae ca. $269.3{\times}221.7{\mu}m$ long also showed three peaks: September 6, September 12 and September 20 for the former, and September 20, September 25 and October 5 for the latter, respectively. About 11 to 12 days was required for D-shaped larvae to develop to umbo-shaped stage. At this intermorphological stage, the daily survival rate was 0.93 with a total survival rate of 45% for the stage. The time required for umbo-shaped larvae to develop to full grown larvae varied from 13 to 15 days with a daily survival rate of 0.93 and with a total survival rate of 36% in the period. Twenty-five to twenty-six days were required for each peak group of the D-shaped larvae to reach a full grown stage, and their total survival rate was 16% during this developmental stage.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.2
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• pp.49-58
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• 2019

There have been studies on the satisfaction, preference, and post occupancy evaluation of urban parks in order to reflect users' preferences and activities, suggesting directions for future park planning and management. Despite using questionnaires that are proven to be affective to get users' opinions directly, there haven been limitations in understanding the latest changes in park use through questionnaires. This study seeks to address the possibility of utilizing the thirdgeneration SNS data, Instagram and Google, to compare behavior patterns and trends in park activities. Instagram keywords and photos representing user's feelings with a specific park name were collected. We also examined reviews, peak time, and popular time zones regarding selected parks through Google. This study tries to analyze users' behaviors, emerging activities, and satisfaction using SNS data. The findings are as follows. People using park near residential areas tend to enjoy programs being operated in indoor facilities and to like to use picnic places. In an adjacent park of commercial areas, eating in the park and extended areas beyond the park boundaries is found to be one of the popular park activities. Programs using open spaces and indoor facilities were active as well. Han River Park as a detached park type offers a popular venue for excercises and scenery appreciation. We also identified companionship characteristics of different park types from texts and photos, and extracted keywords of feelings and reviews about parks posted in $3^{rd}$ generation SNS. SNS data can provide basis to grasp behavioral patterns and satisfaction factors, and changes of park activities in real time. SNS data also can be used to set future directions in park planning and management in accordance with new technologies and policies.

• Journal of the Korean Society of Radiology
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• v.17 no.4
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• pp.541-549
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• 2023

The aim of this study wasto conduct a quantitative analysis of CT image quality according to an algorithm designed to reduce metal artifacts induced by metal components. Ten baseline images were obtained with the standard filtered back-projection algorithm using spectral detector-based CT and CT ACR 464 phantom, and ten images were also obtained on the identical phantom with the standard filtered back-projection algorithm after inducing metal artifacts. After applying the to raw data from images with metal artifacts, ten additional images for each were obtained by applying the virtual monoenergetic algorithm. Regions of interest were set for polyethylene, bone, acrylic, air, and water located in the CT ACR 464 phantom module 1 to conduct compare the Hounsfield units for each algorithm. The algorithms were individually analyzed using root mean square error, mean absolute error, signal-to-noise ratio, peak signal-to-noise ratio, and structural similarity index to assess the overall image quality. When the Hounsfield units of each algorithm were compared, a significant difference was found between the images with different algorithms (p < .05), and large changes were observed in images using the virtual monoenergetic algorithm in all regions of interest except acrylic. Image quality analysis indices revealed that images with the metal artifact reduction algorithm had the highest resolution, but the structural similarity index was highest for images with the metal artifact reduction algorithm followed by an additional virtual monoenergetic algorithm. In terms of CT images, the metal artifact reduction algorithm was shown to be more effective than the monoenergetic algorithm at reducing metal artifacts, but to obtain quality CT images, it will be important to ascertain the advantages and differences in image qualities of the algorithms, and to apply them effectively.

• Journal of Intelligence and Information Systems
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• v.24 no.1
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• pp.183-203
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• 2018

News articles are the most suitable medium for examining the events occurring at home and abroad. Especially, as the development of information and communication technology has brought various kinds of online news media, the news about the events occurring in society has increased greatly. So automatically summarizing key events from massive amounts of news data will help users to look at many of the events at a glance. In addition, if we build and provide an event network based on the relevance of events, it will be able to greatly help the reader in understanding the current events. In this study, we propose a method for extracting event networks from large news text data. To this end, we first collected Korean political and social articles from March 2016 to March 2017, and integrated the synonyms by leaving only meaningful words through preprocessing using NPMI and Word2Vec. Latent Dirichlet allocation (LDA) topic modeling was used to calculate the subject distribution by date and to find the peak of the subject distribution and to detect the event. A total of 32 topics were extracted from the topic modeling, and the point of occurrence of the event was deduced by looking at the point at which each subject distribution surged. As a result, a total of 85 events were detected, but the final 16 events were filtered and presented using the Gaussian smoothing technique. We also calculated the relevance score between events detected to construct the event network. Using the cosine coefficient between the co-occurred events, we calculated the relevance between the events and connected the events to construct the event network. Finally, we set up the event network by setting each event to each vertex and the relevance score between events to the vertices connecting the vertices. The event network constructed in our methods helped us to sort out major events in the political and social fields in Korea that occurred in the last one year in chronological order and at the same time identify which events are related to certain events. Our approach differs from existing event detection methods in that LDA topic modeling makes it possible to easily analyze large amounts of data and to identify the relevance of events that were difficult to detect in existing event detection. We applied various text mining techniques and Word2vec technique in the text preprocessing to improve the accuracy of the extraction of proper nouns and synthetic nouns, which have been difficult in analyzing existing Korean texts, can be found. In this study, the detection and network configuration techniques of the event have the following advantages in practical application. First, LDA topic modeling, which is unsupervised learning, can easily analyze subject and topic words and distribution from huge amount of data. Also, by using the date information of the collected news articles, it is possible to express the distribution by topic in a time series. Second, we can find out the connection of events in the form of present and summarized form by calculating relevance score and constructing event network by using simultaneous occurrence of topics that are difficult to grasp in existing event detection. It can be seen from the fact that the inter-event relevance-based event network proposed in this study was actually constructed in order of occurrence time. It is also possible to identify what happened as a starting point for a series of events through the event network. The limitation of this study is that the characteristics of LDA topic modeling have different results according to the initial parameters and the number of subjects, and the subject and event name of the analysis result should be given by the subjective judgment of the researcher. Also, since each topic is assumed to be exclusive and independent, it does not take into account the relevance between themes. Subsequent studies need to calculate the relevance between events that are not covered in this study or those that belong to the same subject.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.3
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• pp.208-213
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• 2008

Purpose: Generally a whole body bone scan has been known as one of the most frequently executed exams in the nuclear medicine fields. Asan medical center, usually use various gamma camera systems - manufactured by PHILIPS (PRECEDENCE, BRIGHTVIEW), SIEMENS (ECAM, ECAM signature, ECAM plus, SYMBIA T2), GE (INFINIA) - to execute whole body scan. But, as we know, each camera's sensitivity is not same so it is hard to consistent diagnosis of patients. So our purpose is when we execute whole body bone scans, we exclude uncontrollable factors and try to correct controllable factors such as inherent sensitivity of gamma camera. In this study, we're going to measure each gamma camera's sensitivity and study about reasonable correction factors of whole body bone scan to follow up patient's condition using different gamma cameras. Materials and Methods: We used the $^{99m}Tc$ flood phantom, it recommend by IAEA recommendation based on general counts rate of a whole body scan and measured counts rates by the use of various gamma cameras - PRECEDENCE, BRIGHTVIEW, ECAM, ECAM signature, ECAM plus, IFINIA - in Asan medical center nuclear medicine department. For measuring sensitivity, all gamma camera equipped LEHR collimator (Low Energy High Resolution multi parallel Collimator) and the $^{99m}Tc$ gamma spectrum was adjusted around 15% window level, the photo peak was set to 140-kev and acquirded for 60 sec and 120 sec in all gamma cameras. In order to verify whether can apply calculated correction factors to whole body bone scan or not, we actually conducted the whole body bone scan to 27 patients and we compared it analyzed that results. Results: After experimenting using $^{99m}Tc$ flood phantom, sensitivity of ECAM plus was highest and other sensitivity order of all gamma camera is ECAM signature, SYMBIA T2, ECAM, BRIGHTVIEW, IFINIA, PRECEDENCE. And yield sensitivity correction factor show each gamma camera's relative sensitivity ratio by yielded based on ECAM's sensitivity. (ECAM plus 1.07, ECAM signature 1.05, SYMBIA T2 1.03, ECAM 1.00, BRIGHTVIEW 0.90, INFINIA 0.83, PRECEDENCE 0.72) When analyzing the correction factor yielded by $^{99m}Tc$ experiment and another correction factor yielded by whole body bone scan, it shows statistically insignificant value (p<0.05) in whole body bone scan diagnosis. Conclusion: In diagnosing the bone metastasis of patients undergoing cancer, whole body bone scan has been conducted as follow up tests due to its good points (high sensitivity, non invasive, easily conducted). But as a follow up study, it's hard to perform whole body bone scan continuously using same gamma camera. If we use same gamma camera to patients, we have to consider effectiveness of equipment's change by time elapsed. So we expect that applying sensitivity correction factor to patients who tested whole body bone scan regularly will add consistence in diagnosis of patients.

• MISULJARYO - National Museum of Korea Art Journal
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• v.101
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• pp.12-46
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• 2022

Completed in 1467, the Thirteen-story Stone Pagoda of Wongaksa Temple is the last Buddhist pagoda erected at the center of the capital (present-day Seoul) of the Joseon Dynasty. It was commissioned by King Sejo, the final Korean king to favor Buddhism. In this paper, I aim to examine King Sejo's intentions behind celebrating the tenth anniversary of his enthronement with the construction of the thirteen-story stone pagoda in the central area of the capital and the enshrinement of sarira from Shakyamuni Buddha and the Newly Translated Sutra of Perfect Enlightenment (圓覺經). This paper provides a summary of this examination and suggests future research directions. The second chapter of the paper discusses the scriptural background for thirteen-story stone pagodas from multiple perspectives. I was the first to specify the Latter Part of the Nirvana Sutra (大般涅槃經後分) as the most direct and fundamental scripture for the erection of a thirteen-story stone pagoda. I also found that this sutra was translated in Central Java in the latter half of the seventh century and was then circulated in East Asia. Moreover, I focused on the so-called Kanishka-style stupa as the origin of thirteen-story stone pagodas and provided an overview of thirteen-story stone pagodas built around East Asia, including in Korea. In addition, by consulting Buddhist references, I prove that the thirteen stories symbolize the stages of the practice of asceticism towards enlightenment. In this regard, the number thirteen can be viewed as a special and sacred number to Buddhist devotees. The third chapter explores the Buddhist background of King Sejo's establishment of the Thirteen-story Stone Pagoda of Wongaksa Temple. I studied both the Dictionary of Sanskrit-Chinese Translation of Buddhist Terms (翻譯名義集) (which King Sejo personally purchased in China and published for the first time in Korea) and the Sutra of Perfect Enlightenment. King Sejo involved himself in the first translation of the Sutra of Perfect Enlightenment into Korean. The Dictionary of Sanskrit-Chinese Translation of Buddhist Terms was published in the fourteenth century as a type of Buddhist glossary. King Sejo is presumed to have been introduced to the Latter Part of the Nirvana Sutra, the fundamental scripture regarding thirteen-story pagodas, through the Dictionary of Sanskrit-Chinese Translation of Buddhist Terms, when he was set to erect a pagoda at Wongaksa Temple. King Sejo also enshrined the Newly Translated Sutra of Perfect Enlightenment inside the Wongaksa pagoda as a scripture representing the entire Tripitaka. This enshrined sutra appears to be the vernacular version for which King Sejo participated in the first Korean translation. Furthermore, I assert that the original text of the vernacular version is the Abridged Commentary on the Sutra of Perfect Enlightenment (圓覺經略疏) by Zongmi (宗密, 780-841), different from what has been previously believed. The final chapter of the paper elucidates the political semantics of the establishment of the Wongaksa pagoda by comparing and examining stone pagodas erected at neungsa (陵寺) or jinjeonsawon (眞殿寺院), which were types of temples built to protect the tombs of royal family members near their tombs during the early Joseon period. These stone pagodas include the Thirteen-story Pagoda of Gyeongcheonsa Temple, the Stone Pagoda of Gaegyeongsa Temple, the Stone Pagoda of Yeongyeongsa Temple, and the Multi-story Stone Pagoda of Silleuksa Temple. The comparative analysis of these stone pagodas reveals that King Sejo established the Thirteen-story Stone Pagoda at Wongaksa Temple as a political emblem to legitimize his succession to the throne. In this paper, I attempt to better understand the scriptural and political semantics of the Wongaksa pagoda as a thirteen-story pagoda. By providing a Korean case study, this attempt will contribute to the understanding of Buddhist pagoda culture that reached its peak during the late Goryeo and early Joseon periods. It also contributes to the research on thirteen-story pagodas in East Asia that originated with Kanishka stupa and were based on the Latter Part of the Nirvana Sutra.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.1
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• pp.15-26
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• 1994

To understand the relative contribution of varietal and environmental variation on various grain quality components in rice, grain appearance, milling recovery, several physicochemical properties of rice grain and texture or palatability of cooked rice for milled rice materials of seven cultivars(five japonica & two Tongil-type), produced at six locations of the middle and southern plain area of Korea in 1989, were evaluated and analyzed the obtained data. Highly significant varietal variations were detected in all grain quality components of the rice materials and marked locational variations with about 14-54% portion of total variation were recognized in grain appearance, milling recovery, alkali digestibility, protein content, K /Mg ratio, gelatinization temperature, breakdown and setback viscosities. Variations of variety x location interaction were especially large in overall palatability score of cooked rice and consistency or set- back viscosities of amylograph. Tongil-type cultivars showed poor marketing quality, lower milling recovery, slightly lower alkali digestibility and amylose content, a little higher protein content and K /Mg ratio, relatively higher peak, breakdown and consistency viscosities, significantly lower setback viscosity, and more undesirable palatability of cooked rice compared with japonica rices. The japonica rice varieties possessing good palatability of cooked rice were slightly low in protein content and a little high in K /Mg ratio and stickiness /hardness ratio of cooked rice. Rice 1000-kernel weight was significantly heavier in rice materials produced in Iri lowland compared with other locations. Milling recovery from rough to brown rice and ripening quality were lowest in Milyang late-planted rice while highest in Iri lowland and Gyehwa reclaimed-land rice. Amylose content of milled rice was about 1% lower in Gyehwa rice compared with other locations. Protein content of polished rice was about 1% lower in rice materials of middle plain area than those of southern plain regions. K/Mg ratio of milled rice was lowest in Iri rice while highest in Milyang rice. Alkali digestibility was highest in Milyang rice while lowest in Honam plain rice, but the temperature of gelatinization initiation of rice flour in amylograph was lowest in Suwon and Iri rices while highest in Milyang rice. Breakdown viscosity was lowest in Milyang rice and next lower in Ichon lowland rice while highest in Gyehwa and Iri rices, and setback viscosity was the contrary tendency. The stickiness/hardness ratio of cooked rice was slightly lower in southern-plain rices than in middle-plain ones, and the palatability of cooked rice was best in Namyang reclaimed-land rice and next better with the order of Suwon$\geq$Iri$\geq$Ichon$\geq$Gyehwa$\geq$Milyang rices. The rice materials can be classified genotypically into two ecotypes of japonica and Tongil-type rice groups, and environmentally into three regions of Milyang, middle and Honam lowland by the distribution on the plane of 1st and 2nd principal components contracted from eleven grain quality properties closely associated with palatability of cooked rice by principal component analysis.