• Journal of Marine Life Science
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• v.2 no.1
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• pp.20-26
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• 2017

In this study, we evaluated the toxic effects of heavy metals (As, Cr and Pb) on the population growth rate (r) of the marine diatom, Skeletonema costatum. The r of the species was determined after 96 h (4 days) exposure to As (0, 0.31, 0.63, 1.25, 2.50 and 5.00 mg L^-1), Cr (0, 0.16, 0.31, 0.63, 1.25 and 2.50 mg L^-1) and Pb (0, 1.25, 2.50, 5.00, 10.00 and 20.00 mg L^-1). It was observed that r in the control (absence of As, Cr and Pb) were greater than 0.04, however suddenly decreased with increased heavy metal concentrations. As, Cr and Pb reduced r in a dose-dependent manner and a significant reduction were occurred at concentration of greater than 0.31, 0.31 and 5.00 mg L^-1, respectively. Based on the toxicity, the heavy metal were ranked as Cr>As>Pb, with EC₅₀ (50% effective concentration) values of 0.80, 2.57 and 13.88 mg L^-1, respectively. The lowest-observed-effective-concentration (LOEC) of r in exposed to As, Cr and Pb were 0.63, 0.63 and 10.00 mg L^-1, respectively. Precisely, a concentration of greater than 0.63 mg L^-1 of As, 0.63 mg L^-1 of Cr and 10.00 mg L^-1 of Pb in marine ecosystems induced toxic effect on the r of S. costatum. Based on our results, we suggested that the r of S. costatum might be a useful bio-indicator for the toxicity assessment of heavy metals on the producer in marine ecosystems.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.4
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• pp.268-273
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• 2023

The present study estimated rumen fermentation characteristics and greenhouse gas emissions of different forages. Alfalfa, timothy, tall fescue, Italian ryegrass, and rice straw as the main forage sources for Hanwoo were used in the present study. Crude protein was highest in alfalfa but lowest in rice straw (p<0.05). Ether extract was higher in alfalfa and Italian ryegrass than in the other forages (p<0.05). Crude ash was highest in rice straw but lowest in tall fescue (p<0.05). Neutral detergent fiber was highest in tall fescue but lowest in alfalfa (p<0.05). Acid detergent fiber was highest in Italian ryegrass and rice straw but lowest in alfalfa (p<0.05). In vitro digestibilities of dry matter (DMD) and neutral detergent fiber (NDFD) were highest in timothy but lowest in rice straw (p<0.05). Rumen pH was highest (p<0.05) in alfalfa, while ammonia-N was higher (p<0.05) in alfalfa and Italian ryegrass than in the other forages. Total volatile fatty acid was highest (p<0.05) in timothy, while acetate and propionate were highest (p<0.05) in alfalfa and rice straw, respectively. Acetate to propionate ratio was higher (p<0.05) in alfalfa, timothy, and Italian ryegrass than in rice straw. Rice straw had lowest total gas (mL) (p<0.05) but highest its per DMD and NDFD. Rice straw had higher (p<0.05) CO₂ (per DMD and NDFD) compared to alfalfa (per DMD and NDFD), timothy (per DMD and NDFD), tall fescue (per NDFD), and Italian ryegrass (per DMD). Again, rice straw had higher (p<0.05) CH₄ (per DMD and NDFD) compared to timothy (per DMD and NDFD) and tall fescue (per NDFD). Therefore, this study indicates that timothy has a higher nutrient digestibility and volatile fatty acid in the rumen leading to a reduction of greenhouse gas emission.

• Journal of Venture Innovation
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• v.4 no.2
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• pp.29-42
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• 2021

The stress on finding a job is also increasing in a situation where the difficulty in finding a job is aggravating due to the COVID-19 pandemic. In this study, the major satisfaction of college students was subdivided into subject satisfaction and relationship satisfaction, and the relationship between these and job-seeking stress was investigated. In addition, We tried to find out whether there is a difference in the influence relationship between these majors according to their current major, that is, whether they majored in a science, engineering major or a social science major. The population for the study was the students currently enrolled in the 4th grade, and the research sample was obtained from students of H and N universities in the metropolitan area. A total of 220 people were analyzed, 110 people from science and engineering and 110 from social sciences. For analysis, SPSS 24.0 and Process Macro 5.0 were used. The empirical analysis results are as follows. First, subject satisfaction had a negative (-) effect on job-seeking stress. Second, relationship satisfaction also had a significant negative (-) effect on job-seeking stress. Third, there was a significant difference between science, engineering students and social science students in the effect of subject satisfaction on job-seking stress. Fourth, in the effect of relationship satisfaction on job-seeking stress, there was also a significant difference between science, engineering students and social science students. Therefore, the higher the satisfaction with the major you are majoring in, the lower the job-seeking stress, and the extent of this decrease is social science students were larger than science, engineering students. It is necessary to be cautious in generalizing the results of this study, which was made in the context of the COVID-19 pandemic. Based on the empirical analysis results, the academic and practical implications of this study are presented.

• Korean Journal of Radiology
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• v.25 no.1
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• pp.11-23
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• 2024

Objective: To investigate whether reader training improves the performance and agreement of radiologists in interpreting unenhanced breast magnetic resonance imaging (MRI) scans using diffusion-weighted imaging (DWI). Materials and Methods: A study of 96 breasts (35 cancers, 24 benign, and 37 negative) in 48 asymptomatic women was performed between June 2019 and October 2020. High-resolution DWI with b-values of 0, 800, and 1200 sec/mm² was performed using a 3.0-T system. Sixteen breast radiologists independently reviewed the DWI, apparent diffusion coefficient maps, and T1-weighted MRI scans and recorded the Breast Imaging Reporting and Data System (BI-RADS) category for each breast. After a 2-h training session and a 5-month washout period, they re-evaluated the BI-RADS categories. A BI-RADS category of 4 (lesions with at least two suspicious criteria) or 5 (more than two suspicious criteria) was considered positive. The per-breast diagnostic performance of each reader was compared between the first and second reviews. Inter-reader agreement was evaluated using a multi-rater κ analysis and intraclass correlation coefficient (ICC). Results: Before training, the mean sensitivity, specificity, and accuracy of the 16 readers were 70.7% (95% confidence interval [CI]: 59.4-79.9), 90.8% (95% CI: 85.6-94.2), and 83.5% (95% CI: 78.6-87.4), respectively. After training, significant improvements in specificity (95.2%; 95% CI: 90.8-97.5; P = 0.001) and accuracy (85.9%; 95% CI: 80.9-89.8; P = 0.01) were observed, but no difference in sensitivity (69.8%; 95% CI: 58.1-79.4; P = 0.58) was observed. Regarding inter-reader agreement, the κ values were 0.57 (95% CI: 0.52-0.63) before training and 0.68 (95% CI: 0.62-0.74) after training, with a difference of 0.11 (95% CI: 0.02-0.18; P = 0.01). The ICC was 0.73 (95% CI: 0.69-0.74) before training and 0.79 (95% CI: 0.76-0.80) after training (P = 0.002). Conclusion: Brief reader training improved the performance and agreement of interpretations by breast radiologists using unenhanced MRI with DWI.

• Phonetics and Speech Sciences
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• v.16 no.2
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• pp.49-58
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• 2024

This study aimed to compare the acoustic measurements of speech samples recorded from individuals with normal voices using various devices: the Computerized Speech Lab (CSL), a unidirectional wired pin-microphone (WIRED) suitable for smartphones, the built-in omnidirectional microphone (SMART) of smartphones, and Bluetooth-connected wireless earphones, specifically the Galaxy Buds2 Pro (WIRELESS). This study included 40 normal adults (12 males and 28 females) who had not visited an otolaryngologist for respiratory diseases within the past three months. Participants performed sustained vowel /a/ phonation for four seconds and reading tasks with sentences ("Walk") and paragraphs ("Autumn") in a sound-treated booth. Recordings were simultaneously conducted using the four different devices and synchronized based on the CSL-recorded samples for analysis using the MDVP, ADSV, and VOXplot programs. Compared with CSL, the Cepstral Spectral Index of Dysphonia (CSID_V, CSID_S) and Acoustic Voice Quality Index (AVQI) values were lower in the WIRED and higher in the SMART. The opposite trend was observed for the L/H spectral ratios (SR_V and SR_S), and the WIRELESS demonstrated task-specific discrepancies. Furthermore, both the fundamental frequency (F0) and the cepstral peak prominence of the vowel samples (CPP_V) had intraclass correlation coefficient (ICC) values above 0.9, indicating high reliability. These variables, F0 and CPP_V were considered highly reliable for voice recordings across different microphone types. However, caution should be exercised when analyzing and interpreting variables such as the SR, CSID, and AVQI, which may be influenced by the type of microphone used.

• Journal of Animal Science and Technology
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• v.45 no.6
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• pp.923-932
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• 2003

This study was carried out to estimate the effects of breed and environment such as sex, test station, test year, test season, parity, initial and final weight on average daily gain, age at 90kg, backfat thickness, feed efficiency, lean percent and selection index on the basis of the performance data collected from 25,790 pigs of Duroc, Yorkshire and Landrace breeds which were performance-tested at the Korea Swine Testing Station from 1991 to 2002. The results obtained in the study are summarized as follows; 1. The means of the major economic traits were estimated as 959.95${\pm}$0.699g for average daily gain, 138.36${\pm}$0.072days for age at 90kg, 1.41${\pm}$0.001cm for backfat thickness, 2.33${\pm}$0.001 for feed efficiency, 56.71${\pm}$0.018% for lean percent and 221.65${\pm}$0.113 for selection index. 2. The effect of breed was statistically significant for all studied traits. Briefly, Duroc showed the best performance for the average daily gain and age at 90kg. Landrace had the best performances for the backfat thickness and lean meat percent. In feed efficiency and selection index, Yorkshire had a better score than other breeds. 3. The least-squares means of female and male for the traits studied were 923.05${\pm}$1.289g and 974.53${\pm}$0.856g for average daily gain, 139.74${\pm}$0.145days and 137.21${\pm}$0.097days for age at 90kg, 1.49${\pm}$0.002cm and 1.39${\pm}$0.002cm for backfat thickness, 2.43${\pm}$0.002 and 2.28${\pm}$0.002 for feed efficiency, 56.43${\pm}$0.034% and 56.81${\pm}$0.023% for lean percent and 211.37${\pm}$0.194 and 224.61${\pm}$0.129 for selection index. Therefore, males were superior to females for all traits examined. 4. The effect of test station was statistically significant for all traits except for selection index. Performances for age at 90kg, backfat thickness, feed efficiency and lean meat percent collected from Test station 2 were higher than those from Test station 1. However, Test station 1 showed better average daily gain. 5. The initial weight and final weight included as a covariate in this study had a significant influence on average daily gain, age at 90kg, backfat thickness, feed efficiency and selection index. From the absolute values of the estimated regression coefficients, it was inferred that the final weight had greater effect for the investigated traits than the initial weight.

• Journal of Intelligence and Information Systems
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• v.22 no.1
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• pp.107-118
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• 2016

The advent of 5G mobile communications, which is expected in 2020, will provide many services such as Internet of Things (IoT) and vehicle-to-infra/vehicle/nomadic (V2X) communication. There are many requirements to realizing these services: reduced latency, high data rate and reliability, and real-time service. In particular, a high level of reliability and delay sensitivity with an increased data rate are very important for M2M, IoT, and Factory 4.0. Around the world, 5G standardization organizations have considered these services and grouped them to finally derive the technical requirements and service scenarios. The first scenario is broadcast services that use a high data rate for multiple cases of sporting events or emergencies. The second scenario is as support for e-Health, car reliability, etc.; the third scenario is related to VR games with delay sensitivity and real-time techniques. Recently, these groups have been forming agreements on the requirements for such scenarios and the target level. Various techniques are being studied to satisfy such requirements and are being discussed in the context of software-defined networking (SDN) as the next-generation network architecture. SDN is being used to standardize ONF and basically refers to a structure that separates signals for the control plane from the packets for the data plane. One of the best examples for low latency and high reliability is an intelligent traffic system (ITS) using V2X. Because a car passes a small cell of the 5G network very rapidly, the messages to be delivered in the event of an emergency have to be transported in a very short time. This is a typical example requiring high delay sensitivity. 5G has to support a high reliability and delay sensitivity requirements for V2X in the field of traffic control. For these reasons, V2X is a major application of critical delay. V2X (vehicle-to-infra/vehicle/nomadic) represents all types of communication methods applicable to road and vehicles. It refers to a connected or networked vehicle. V2X can be divided into three kinds of communications. First is the communication between a vehicle and infrastructure (vehicle-to-infrastructure; V2I). Second is the communication between a vehicle and another vehicle (vehicle-to-vehicle; V2V). Third is the communication between a vehicle and mobile equipment (vehicle-to-nomadic devices; V2N). This will be added in the future in various fields. Because the SDN structure is under consideration as the next-generation network architecture, the SDN architecture is significant. However, the centralized architecture of SDN can be considered as an unfavorable structure for delay-sensitive services because a centralized architecture is needed to communicate with many nodes and provide processing power. Therefore, in the case of emergency V2X communications, delay-related control functions require a tree supporting structure. For such a scenario, the architecture of the network processing the vehicle information is a major variable affecting delay. Because it is difficult to meet the desired level of delay sensitivity with a typical fully centralized SDN structure, research on the optimal size of an SDN for processing information is needed. This study examined the SDN architecture considering the V2X emergency delay requirements of a 5G network in the worst-case scenario and performed a system-level simulation on the speed of the car, radius, and cell tier to derive a range of cells for information transfer in SDN network. In the simulation, because 5G provides a sufficiently high data rate, the information for neighboring vehicle support to the car was assumed to be without errors. Furthermore, the 5G small cell was assumed to have a cell radius of 50-100 m, and the maximum speed of the vehicle was considered to be 30-200 km/h in order to examine the network architecture to minimize the delay.

• Korean Journal of Psychosomatic Medicine
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• v.4 no.2
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• pp.269-276
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• 1996

A theroretical study was made on the psychodynamism of somatoform disorder. Somatoform disorder is caused by a defense mechanism of somatization. Somatization is the tendency to react to stimuli(drives, defenses, and conflict between them) physically rather than psychically(Moore, 1990). Ford(1983) said it is a way of life, and Dunbar(1954) said it is the shift of psychic energy toward expression in somatic symptoms. As used by Max Shur(1955), somatization links symptom formation to the regression that may occur in response to acute and chronic conflict. In the neurotic individual psychic conflict often provokes regressive phenomena that may include somatic manifestations characteristic of an earlier developmental phase. Schur calls this resomatization. Pain is the most common example of a somatization reaction to conflict. The pain has an unconscious significance derived from childhood experiences. It is used to win love, to punish misdeeds, as well as a means to amend. Among all pains, chest pain has a special meaning. Generally speaking, 'I have pain in my chest' is about the same as 'I have pain in my mind'. The chest represent the mind, and the mind reminds us about the heart. So we have a high tendency to recognize mental pain as cardiac pain. Kellner(1990) said rage and hostility, especially repressed hostility, are important factors in somatization. In 'Psychoanalytic Observation on Cardiac Pain', psychoanalyst Bacon(1953) presented clinical cases of patients who complained of cardiac pain in a psychoanalytic session that spread from the left side of their chests down their left arms. The pain was from rage and fear which came after their desire to be loved was frustrated by the analyet. She said desires related to cardiac pain were dependency needs and aggressions. Empatic relationship and therapeutic alliances are indispensable to psychotherapy in somatoform disorder. The beginning of therapy is to discover a precipitating event from the time their symptoms have started and to help the patient understand a relation between the symptom and precipitating event. Its remedial process is to find and interpret a intrapsychic conflict shown through the symptoms of the patient. Three cases of somatoform disorder patients treated based on this therapeutic method were introduced. The firt patient, Mr. H, had been suffering from hysterical aphasia with repressed rage as ie psychodynamic cause. An interpretation related to the precipitating event was given by written communication, and he recovered from his aphasia after 3 days of the session. The second patient was a dentist in a cardiac neurosis with agitation and hypochondriasis, whose psychodynamism was caused by a fear that he might lose his father's love. His symptom was also interpreted in relation to the precipitating event. It showed the patient a child-within afraid of losing his father's love. His condition improved after getting a didactic interpretation which told him, to be master of himself, The third patient was a lady transferred from the deparment of internal medicine. She had a frequent and violent fit of chest pains, whose psychodynamic cause was separation anxiety and a rage due to the frustration of dependency needs. Her symptom vanished dramatically when she wore a holler EKG monitor and did not occur during monitoring. By this experience she found her symptom was a psychogenic one, and a therapeutic alliance was formed. later in reguar psychotherapy sessions, she was told the relaton between symptoms and precipitating events. Through this she understood that her separation anxiety was connected to the symptom and she became less terrifide when it occurred. Now she can travel abroad and take well part in social activities.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.371-384
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• 1982

Highly cold tolerant varieties are requested not only at high latitute cool area but also tropical high elevated areas, and the required tolerance is different from location to location. IRRI identified 6 different types of cold tolerance required in the world for breeding purpose; a) Hokkaido type, b) Suweon type, c) Taipei 1st season type, d) Taipei 2nd season type, e) Tropical alpine type and, f) Bangladesh type. The cold tolerance requested in Korea is more eargent in Tongil group cultivars and their required tolerance is the one such as the physiological activities at low temperature are as active as in Japonica group cultivars at least during young seedling stage and reproduction stage. With conventional Japonica cultivars, such cold tolerant characters are requested as short growth duration but stable basic vegetative growth, less sensitive to high temperature and less prolonged growth duration at low temperature. The methods screening for cold tolerance were developed rapidly after the Tongil cultivar was reliesed. The facilities of screening for cold tolerance, such as, low temperature incubator, cold water tank, growth cabinet, phytotron, cold water nursery in Chuncheon, breeding nursery located in Jinbu, Unbong and Youngduk, are well established. Foreign facilities such as, cold water tank with the rapid generation advancement facilities, cold nurseries located in Banaue, Kathmandu and Kashimir may be available for the screening of some limitted breeding materials. For the reference, screening methods applied at different growth stages in Japan are introduced. The component characters of cold tolerance are not well identified, but the varietal differences in a) germinability, b) young seedling growth, c) rooting, d) tillering, e) discolation, f) nutrition uptake, g) photosynthesis rate, h) delay in heading, i) pollen sterility, and j) grain fertility at low temperature are reported to be distinguishable. Relationships among those traits are not consistent. Reported studies on the inheritance of cold tolerance are summarized. Four or more genes are controlling low temperature germinability, one or several genes are controlling seedling tolerance, and four or more genes are responsible for the pollen fertility of the rice treated with cold air or grown in the cold water nursery. But most of those data indicate that the results may come out in different way if those were tested at different temperature. Many cold tolerant parents among Japonicas, Indicas and Javanicas were identified as the results of the improvement of cold tolerance screening techniques and IRTP efforts and they are ready to be utilized. Considering a) diversification of germ plasm, b) integration of resistances to diseases and insects, c) identification of adaptability of recommending cultivars and, d) systematic control of recommending cultivars, breeding strategies for short term and long term are suggested. For short term, efforts will be concentrated mainly to the conventional cultivar group. Domestic cultivars will be used as foundation stock and ecologically different foreign introductions such as from Hokkaido, China or from Taiwan, will be used as cross parents for the adjustment of growth durations and synthsize the prototype of tolerances. While at the other side, extreme early waxy Japonicas will be crossed with the Indica parents which are identified for their resistances to the diseases and insects. Through the back corsses to waxy Japonicas, those Indica resistances will be transfered to the Japonicas and these will be utilized to the crosses for the improvement of resistances of prototype. For the long term, efforts will be payed to synthsize all the available tolerances identified any from Japonicas, Indicas and Javanicas to diversify the germ plasm. The tolerant cultivars newly synthsized, should be stable and affected minimum. to the low temperature at all the growing stages. The resistances to the diseases and insects should be integrated also. The rapid generation advancement, pollen culture and international cooperations were emphasized to maximize the breeding efficiency.

• Korean Journal of Weed Science
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• v.10 no.4
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• pp.294-304
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• 1990

For the survey of weed distribution in the cultivated upland of Korea, weed species were investigated at 2 field by crop of 2 myon per kun in 81 kun selected among the 139 kun of the whole country. 232 species in 46 families were observed, totally. From among the result, 165 species in 39 families the in winter crop field, 189 species in 41 families in the summer crop field were classified. 122 species in 34 families were emerged the from the upland crop field of the whole season. Further more, in the 10 dominant weed species which emerged from upland crop field, Alopecurus aequalis, Chenopodium album, slellaria media, Galium spurieum, Capsella bursa-pastoris and Rorippa islandica were dominated in the winter upland and paddy field, and that Erigeron canadensis, Cyperus amuricus, Equisetum arvense and Arenaria serpyllifolia were dominated in the winter upland field, additionally. Stellaria alsine, Bothriospermum tenellum, Trigonotis peduncularis and Polygonum arviculare were dominated in the winter cropping on drained paddy field, additionally. In the summer crop field, Digitaria sanguinalis, Portulaca oleracea, Acalypha australis, Echinochloa crus-galli, Setaria viridis, Persicaria hydropiper, Amaranthus lividus, commelina communis, Chenopodium album and Cyperecs amuricus were dominated.