(A) textual analysis of university promotional brochures in Korea and the US

김정은 Chonnam National University 2018 국내박사

The purpose of the study was to compare the marketization of higher education in Korean universities and the US universities. Twenty-five English-language versions of university brochures in each country were compared using corpus-based analysis, move structure analysis and transitivity analysis. The investigation focused on describing and interpreting linguistic features which show whether university brochures are influenced by the marketization of higher education. Further, analyzing the relationship between the two parties, namely the university and students, reveals how the university positions itself for effective promotion. The results indicate that the university brochure is a mixed-genre of information and promotion. The contents it delivers can be classified as information; however, the delivery of the contents is promotional. The universities in the US university brochures (UUBs) stake out their position as service providers. They try to create conversational atmosphere and equal relationship with students. On the other hand, universities in Korean university brochures (KUBs) take a role of introducers of future careers. They promote students’ career paths or career possibilities. As promotional genres are formed based on the lifestyle and values of society members, messages in the genre represent cultural values. The reasons why universities in the UUBs and KUBs take a different role have been found from the origin of a university in each culture. The results discuss the similarities and differences of the marketization of higher education between Korea and the US. This genre-based research can contribute to Korean EFL learners in recognizing a cultural difference in one genre.

D-homothetic transforms on contact metric manifolds

황강 Chonnam National University 2017 국내석사

D-HOMOTHETIC TRANSFORMS ON CONTACT METRIC MANIFOLDS GANG HWANG Department of Mathematics & Statistics Graduate School, Chonnam National University ( Supervised by Professor Jong Taek Cho) Abstract In this thesis, we study the D-homothetic transforms of contact metric manifolds. Then we obtain the transforms of curvature tensor, Ricci curvature tensor, and their covariant differentiations.

Factors at play in extraposing English relative clauses

이승한 Chonnam National University 2017 국내박사

English relative clause extraposition (hereafter RCE) shows a discontinuous dependency, violating the typical X-bar phrase structure. This dissertation provides three different perspectives on why the English relative clause is extraposed. One is to investigate discourse and grammatical properties of RCE construction and then draw a meaningful conclusion that RCE construction cannot avoid the influence of grammatical heaviness. Another approach is to suggest that RCE construction is triggered to maximize focus effect (i.e., degree of pitch increase). The other is to introduce constraint-based grammar in order to analyze RCE construction. In doing so, we embark on analyzing the corpus data of 597 RCE examples extracted from BYU-BNC (Brigham Young University-British National Corpus) and COCA (Corpus of Contemporary American English). One of prominent corpus findings of RCE construction is indefiniteness of a subject NP as well as passive voice, thereby being characterized with [AGENT -] feature. Heavy grammatical weight of an extraposed relative clause provides a plausible reason why RCE construction is preferred over canonical construction (i.e., non-RCE). Which-relative pronoun is the most widely used, and any relative pronouns are prohibited from being deleted in the postposed relative clause. Infinitival RCE construction has similar grammatical behavior with finite RCE construction, but interestingly it does not have a that-extraposed relative clause. We assume the information structure of RCE construction and then propose the role of an extraposed relative pronoun as a cohesive device, thus providing the discourse-based classification of RCE construction: Discourse-Old-Old-RCE, Discourse-Old-New-RCE, Discourse-New-Old-RCE, and Discourse-New-New-RCE. Discourse-New-Old-RCE stays on the top in frequency rate, implying that RCE construction is more suitable when a writer or speaker wants to convey discourse-new information in a subject NP, and puts more given information in an extraposed relative clause. In addition, we introduce multinominal logistic regression to determine whether each type of RCE construction is primarily predicted by the indefiniteness/ definiteness of a subject NP, types of predicate (i.e., passive, presentative intransitive, and predicative complement of copula be), and/or grammatical weight (i.e., subject NP-to-extraposed RC length ratio). The definiteness of a subject NP and high length ratio are crucial factors to bring about Discourse-Old-Old-RCE and Discourse-Old-New-RCE whereas the indefiniteness of a subject NP is a main predictor of Discourse-New-Old-RCE and Discourse-New-New-RCE. Interestingly, only Discourse-New-Old-RCE has a negative correlation with the subject NP-to-extraposed RC length ratio. This finding supports that the grammatical weight is a main factor to result in the extraposition of a restrictive relative clause. On the other hand, we challenge a totally different perspective on RCE construction, called focus effect. We measure the duration of silent pause between the ending point of a predicate and the starting point of an extraposed relative pronoun. Unexpectedly, the duration of unfilled pause in RCE construction decreases as the constituents within an extraposed relative clause increase more and more. This idiosyncratic finding again leads us to find the answer by measuring the degree of pitch increase (i.e., focus effect) on focused parts of several constructions: it-cleft, pseudo-cleft, RCE and non-RCE constructions. Thus, it is assumed that RCE construction would be triggered because it produces stronger focus effect than non-RCE construction. In particular, Focus Cohesion Principle that we propose gives us a plausible explanation about the decreasing duration of silent pause. It says that a focused element followed by its adjacent constituents tends to merge and haul as many as possible within a specific phrase boundary, thereby resulting in the reduction of pause, collapse of grammatical function, and difficulty in understanding an utterance. In order to support Focus Cohesion Principle, we conduct questionnaire survey where one English native and one advanced Korean learner of English disregard a grammatical function (i.e., extraposed relative pronoun as a cohesive device), and consequently they misinterpret RCE sentences as sequential ordering (i.e., non-restrictive relative perspective). We provide the analysis of RCE construction in terms of Sign-Based Construction Grammar which enables RCE construction to inherits constraints through multiple inheritance hierarchy and then specifies syntactic, semantic, pragmatic, and phonological properties of RCE construction. We propose Rel-Extra-Cl Construction licensed by stative-verb-lexeme, declarative, and Head-Noun-Rel-Extra Constructions in order to explain RCE structure. In addition, we assume Head-Extra Principle to ensure that the extraposition feature is percolated at the top node of RCE sentence. Last, we claim that teaching corpus-based RCE construction should deductively proceed with explicit form-focused instruction in L2 classroom. This is closely related to the assumption that the corpus-based grammar teaching enables L2 teachers to provide L2 learners with appropriate conditions for a specific use of language. Thus, we propose a pedagogical strategy with various variables to define the acquisition of corpus-based RCE construction: age, proficiency level, register, markedness, transferability, structuralization, strategy, generalization process, motivation. Considering all these facts, a conclusive statement is drawn that L2 learners should learn RCE construction deductively with the help of explicit grammar teaching.

Overpassivization in the use of unaccusatives by Korean EFL learners

유문영 Chonnam National University 2017 국내박사

This study aims to investigate why Korean EFL learners overpassivize English unaccusatives. To identify learners' overpassivization patterns, a corpus analysis of their writing samples was conducted first. The first study attempts to find out whether two types (Alternating and Non-alternating) of unaccusatives and the subject animacy of the verbs influences the overpassivization error pattern. Non-native students (NNS) corpus data were analyzed by WordSmith Tools to see the frequency of the overpassivization error. It shows that the error rates of non-alternating unaccusatives are higher than those of alternating unaccusatives but that it has no significant difference in error rates between the two types of unaccusatives. It was also found that the overpassivization error rate can differ according to the animacy of subject only in the case of alternating unaccusatives. The results of the first study demonstrate that the animacy can partially play a significant role in the overpassivization error pattern. The second study also attempts to find out whether the external and internal causation, alternation of verb, and English proficiency affect the overpassivization error pattern. Grammaticality Judgement test with 30 items was conducted on 183 Korean EFL learners not majoring in English from G University. The participants are divided into three groups (High, Middle, and Low) by their English grades on the Korean Scholastic Aptitude Test (SAT). The experiment shows that there is no significant difference found in the overpassivization errors between the external and internal causation and between alternating and non-alternating unaccusatives. However, it demonstrates that there is significant difference found in the errors among the three groups. The middle group made the most errors among three groups, thereby demonstrates the U-shaped learning development. It is likely that their errors were most affected by natural features of the verb, agentivity, and L1 transfer. Taking into account above-mentioned study and survey results, it can be concluded that non-linguistic factors, as well as linguistic factors, may affect Korean EFL learners to make overpassivization errors. In future studies, more non-linguistic factors will be considered for analysis to investigate how they pose difficulties to the learners when deciding which voice form to use.

Classification of radiopaque foreign bodies encountered in dental practice

황슬애 Chonnam National University 2019 국내박사

Objective: The purpose of the present study was to collect and classify radiopaque foreign bodies discovered on oral and maxillofacial radiographs. Materials and methods: We searched the Picture Archiving and Communication System of Chonnam National University Dental Hospital for images of radiopaque foreign bodies. Thirty key words were used to search the Study Comment to identify images with radiopaque foreign bodies, acquired between November 2008 and March 2017. A total of 503 cases of radiopaque foreign bodies were selected from among the recovered images. These radiopaque foreign bodies were sorted into 19 types. These were divided into two categories according to whether the foreign bodies were inserted intentionally or unintentionally. These categories were then subdivided into five groups based on the reasons for or causes of their insertion: 1. Treatment, 2. Esthetics, 3. Cultural, 4. Iatrogenesis, and 5.Accident. Results: In this study, approximately the same number of foreign bodies were inserted intentionally (48%) and unintentionally (52%).The reasons for foreign body insertion were as follows: 1.Treatment (41%), 2. Esthetics (7%), 3. Cultural(<1%), 4. Iatrogenesis (51%), and 5.Accident (1%). Conclusion: For adequate case management and to avoid unnecessary embarrassment and misinterpretation of unexpected radiopacities, dental clinicians should be familiar with the various types of foreign bodies and should ensure that detailed patient medical/dental history is obtained. 방사선 영상을 촬영하기 전에 모든 가철성 장치와 액세서리를 벗고 촬영함에도 불구하고, 치과방사선 영상에서 치과 의료진들이 예상하지 못하는 방사선 불투과성 이물질들이 종종 나타나곤 한다. 이러한 익숙하지 않은 방사선 불투과성 이물질들은 치과의료진에 의해 잘못 해석될 수 있다. 이 연구의 목적은 치과방사선 영상에서 종종 나타날 수 있는 다양한 방사선 불투과성 이물질 영상들을 분류하고 보여주어 의료진이 이에 익숙해지도록 하고, 해석과 진단에 도움이 되도록 하는 것이다. 본 연구는 전남대학교 치과 병원 PACS를 이용하여 2008년 11월에서 2017년 3월 사이에 촬영 된 방사선 영상을 수집하였다. 30개의 검색어를 사용하여 방사선 불투과성 이물질들을 검색하였으며, 총 503건을 수집하였다. 조사된 방사선 불투과성 이물질들은 19 가지 유형으로 분류하였다. 이물질이 삽입된 목적에 따라, 의도적으로 삽입한 경우 또는 비의도적으로 삽입된 경우, 두 가지 범주로 나누었다. 이 범주들은 이물질이 삽입된 원인에 따라 다음과 같이5개의 그룹으로 세분 되었다 : 1. 치료, 2. 미용, 3. 문화, 4. 의원성, 5. 사고. 본 연구에서 조사된 바로는 의도적으로 삽입된 이물질이 대략 48 % 이었고 비의도적으로 삽입된 이물질은 52 %이었다. 이물질이 삽입된 원인에 따른 분류는 다음과 같았다 : 1. 치료 (41 %), 2. 미용 (7 %) 3. 문화 (1 % 미만), 4. 의원성 (51 %), 사고 (1 %). 치과 임상가들이 방사선 불투과성 이물질들에 대해 잘 알고 있으며, 환자의 병력에 대해 잘 알고 있을 때에, 진료실에서 예기치 않은 방사선 불투과성 이물질을 만나더라도 당황하지 않고 진료를 할 수 있을 것이다.

Effects of explicit instruction on Korean EFL learners' development of phrasal and compound stress

정윤희 Chonnam National University 2016 국내박사

This dissertation investigates the phonetic implementation of phrasal and compound stress produced by Korean learners of English and native speakers of English and the effectiveness of pronunciation instruction on L2 pronunciation improvement. The purpose of the study is twofold: (a) to examine the acoustical correlates of phonetic stress in phrasal and compound words respectively produced by Korean learners of English and native speakers, and (b) to assess student progress in the phonetic implementation of English phrasal and compound stress during a seven-week English speaking class with the explicit and implicit pronunciation instruction respectively. This study is experimental in nature, both classroom-based and laboratory, investigating the effects of different instructional approaches on pronunciation learning. Previous studies on the acoustical correlates used by native speakers in the phonetic implementation of stress have shown that they rely on F0, duration, and intensity in stress production. This study focuses on the use of these three cues by Korean learners of English in stress assignment. The experimental design involves two homogeneous groups of EFL students enrolled in the language program of Chonnam National University, Korea. Pre- and post- tests on two sets of stimuli were administered to participants in all two groups, and native speakers. One set of stimuli contains the sentences that carry the phrasal and compound words for each pair whereas the other set of stimuli contains the sentences with phrasal words only in the simplest syntactic structure. This study found that explicit instruction affected learners' pronunciation development on phrasal and compound stress. The results showed that the native speakers of English implement pitch and intensity as reliable cues to distinguish compounds from their phrasal counterpart whereas Korean learners do not exhibit any acoustical differentiation in compounds and phrases in the pretest. In the posttest, on the other hand, the participants in the explicit group performed acoustic cues of stress in distinguishing compound words from phrasal counterparts as native speakers do whereas the participants in the implicit group did not show improvement on implementing the acoustic cues of stress in distinguishing the target forms. These results suggest that explicit instruction affects learners' pronunciation development on compound and phrasal stress. Pedagogical implications of the findings of this study and suggestions for future research are also presented.

Clinical factors associated with 60-day mortality in patients requiring prolonged mechanical ventilation in the medical intensive care unit

김기현 Chonnam National University 2017 국내석사

Background: In patients requiring prolonged mechanical ventilation (PMV), weaning is difficult and mortality is very high. PMV has been defined recently, by consensus, as the need for ≥ 21 consecutive days of mechanical ventilation (MV) for ≥ 6 hours per day. Purpose: This study was to evaluate the clinical factors associated with 60-day mortality in patients undergoing PMV in medical intensive care units (ICUs). Methods: We retrospectively reviewed 127 patients who were received mechanical ventilation for more than 21 days in the medical ICU at Chonnam National University Hospital in South Korea between January 2005 and December 2014. Patients who underwent surgery or experienced trauma were excluded from this study. Results: Respiratory diseases (66.1%) were the most common reason for ICU admission, followed by cardiovascular diseases (16.5%). Forty-one patients (32.3%) were successfully weaned from mechanical ventilation. In-ICU mortality was 55.1%. The requirement of vasopressor on day 21 of MV and thrombocytopenia on day 21 of MV were the predictors of 60-day mortality in patients with PMV. Conclusion: In the present study, patients requiring PMV have a high mortality rate. The requirement of vasopressor and thrombocytopenia measured on day 21 of MV are prognostic factors associated short term mortality in patients requiring PMV.

Projection of paddy rice productivity using remote sensing data and a grid-based crop model

정승택 Chonnam National University 2018 국내박사

The principal issue for food security continues to be of interest because the global population is steadily increasing and crop productivity is expected to decrease. Accordingly, it is necessary to understand the current circumstances for stable food production and to take countermeasures to satisfy the food demand in the near future through accurate and continuous monitoring of crop productivity. Crop productivity has been traditionally monitored based on statistical data of a crop obtained from a ground survey method. However, limitations of this technique are that it is time-consuming and labor-intensive as well as it cannot consider a spatial variation of fields of interest or an inaccessible area. An image-based remote sensing technique based on aerial or satellite data has been proven to be an excellent approach to complement the limitations of the ground survey method as it enables timely, efficient, and convenient monitoring of crop productivity. Among the various approaches to monitoring crop productivity using image-based remote sensing data, a combination with a crop model is a better promising approach due to being able to reflect crop physiological characteristics using biophysical parameters. This study aims to examine whether (1) remotely sensed images from an unmanned aerial system (UAS) can accurately monitor rice growth conditions based on spectral data, (2) a crop model combined with the UAS-based images can accurately simulate rice growth conditions and yield in a field scale, and (3) the model combined with satellite data can reproduce rice yield and production from regional to national scales. For monitoring of rice growth conditions based on spectral data, a UAS was constructed, which includes an unmanned aerial vehicle (UAV), a multispectral camera, a real-time monitor, and handcrafted portable calibration boards for post radiometric correction using an image processing technique. UAS-based monitoring and field experiments were performed in paddy fields at Chonnam National University (CNU), Gwangju, South Korea in 2013. Spectral reflectance images from the UAS were in statistically acceptable agreement with measured paddy data with a Nash-Sutcliffe efficiency (NSE) range from -37.75 to 0.99 and a root mean square error (RMSE) range from 0.01 to 0.11, respectively. Also, UAS-based normalized difference vegetation indices (NDVI) well represented canopy growth conditions of paddy in fields treated with three different nitrogen regimes. The GRAMI-rice crop model combined with the UAS-based images was used to simulate rice productivity. The GRAMI-rice model was designed to spatiotemporally simulate above ground dry mass (AGDM), leaf area index (LAI), net primary production (NPP), and yield of paddy rice. The model was calibrated using data obtained at the CNU paddy fields in 2013 and applied to simulate paddy productivity grown with conventional farm management practices at the Gimje plain in South Korea in 2014. In model evaluation results, NSE values for all the variables of interest for rice growth and productivity ranged from 0.113 to 0.955. RMSE values between simulated and observed grain yields ranged from -247 to 456 kg ha-1. Also, a study to simulate rice yield and production on a national scale was performed using the GRMAI-rice model combined with satellite images. Data used as input parameters for the model are as follows: (1) vegetation indices (VIs) and solar insolation data estimated from the geostationary ocean color imager (GOCI) and the meteorological imager (MI) of the communication ocean and meteorological satellite (COMS), (2) air temperatures from the Korea local analysis and prediction system (KLAPS), and (3) distribution maps for paddy fields and transplanting dates estimated from the moderate resolution imaging spectroradiometer (MODIS). Estimated paddy fields were in good agreement with the Korea land cover map. The model was calibrated to simulate rice yields using data obtained from 11 counties and applied to 62 counties with an area of more than 5,000 ha in South Korea for four years from 2011 to 2014. Simulated rice yields were in statistically acceptable agreement with the observed data with an NSE range from -0.208 to 0.553 and an RMSE range from 0.326 to 0.441 ton ha-1, respectively. Also, rice productions in 73 counties including the calibration sites were reproduced with an NSE range from 0.668 to 0.698 and an RMSE range from 25.22 to 33.00 kt ha-1, respectively. In conclusion, the present research demonstrated that reliable projection of rice productivity could be achieved from fields to national scales using a crop model combined with image-based remote sensing data.

Predictors of outcome after radiosurgery of intracranial arteriovenous malformations

이슬기 Chonnam National University 2018 국내석사

Objective: Intracranial Arteriovenous malformation (AVM) is one of the most challenging and complicated cerebral lesion. Although stereotactic radiosurgery (SRS) is a widely used modality in the treatment of AVM, the benefits and risks of the procedure are still poorly understood. The author performed a study to review the experience and outcome with SRS for the treatment of AVMs with various features. Materials and Methods: Forty-eight patients with AVMs treated with SRS and followed up postoperatively at Chonnam National University Hospital over 11 years span from 2006 to 2016 by one physician. The mean patient age at treatment was 39.9 years old (range: 7 - 81). The patients underwent radiologic follow up for an average of 45.02 months (range, 4 - 98). Patients who perfomed SRS were instructed to undergo clinical and imaging follow-up for after 3 month from SRS to confirm the perilesional edema. And the patients followed annually by brain Computed Tomography angiogram (CTA). When the brain CTA showed complete obliteration, the patient was performed Magnetic Resonnance Digital Substraction Angiogram (MR-DSA). When MR-DSA showed complete obliteration, transfemoral cerebral angiography (TFCA) was requested. The AVMs were confirmed complete obliteration when TFCA showed obvious disappearance of nidi and draining veins. Radiosurgery-based AVM scales (RBAS, 2011 modification) and Virginia radiosurgery AVM scales (VRAS) were also reviewed in addition to the conventional Spetzler-Martin (S-M) grade. The authors analyzed data with univariate chai-square test and multivariate Cox proportional hazards and logistic regression analysis to identify factors associated with complete obliteration ans RICs. Results: The most common presenting symptoms were hemorrhage (50%) and headache (20.8%) and seizure (8.3%). Mean AVM volume was 4.63ml (range, 0.16 - 27.2) and the mean prescription dose was 21Gy. The overall obliteration rate, including MRA and cerebral angiography, after SRS was 56.25% (27/48). Patients with asymptomatic (p=0.015), non-hemorrhagic presentation (p=0.006), higher prescription dose (p=0.017) showed favorable outcome in multivariate analysis. S-M grade and RBAS and VRAS were not statistically significant predictors of complete obliteration. Radiation induced changes (RICs) occurred in 14 patients (29.2%); 2 patients were symptomatic and no one had permanent neurologic deficit. Female sex (p=0.045), hemorrhagic presentation (p=0.042), and higher prescription dose (p=0.046) were independently associated with RICs after SRS. Conclusion: Although this study has several limitations, present study has shown that asymptomatic patient, non-hemorrhagic presentation, higher prescription dose can be used practically to predict complete obliteration. And we also revealed that measuring gender of patient, hemorrhagic presentation, lower prescription dose can be effective in reducing RICs.

Association between TCF7L2 polymorphism and the risk of colorectal cancer in Korean population

이란 Chonnam National University 2016 국내석사

Purpose: The associations between TCF7L2 gene and risk of several malignancies have been reported though, inconsistent findings between different populations were reported. The aim of this study was to investigate association between the newly identified locus and CRC risk in Korean population to make clear the attribution of T2D for CRC carcinogenesis. Method: This Case-control study was conducted among 6,138 CRC patients from the Chonnam National University Hwasun Hospital and 4,367 cancer-free community controls. TCF7L2 rs11196172 genotyping were performed by TaqMan assay in a real-time PCR assay. Multivariate logistic regression was performed and 2 adjusted odds ratios (aORs) and their 95% confidence intervals (CI) were calculated using age, sex, smoking and BMI as covariates. Results: Adjusted OR for age, sex, smoking status, and BMI of A allele, compared to G allele, was 1.083 (95% CI 1.011 - 1.159). The significant higher risk of CRC in A allele was remained after additional adjustment of diabetes status (aOR 1.072, 95% CI 1.003-1.146). As compared to G allele without DM, the risks of CRC were higher in A allele with DM and A allele without DM (aOR 1.099, 95% CI 1.019-1.186 and aOR 1.141, 95% CI 1.034-1.258, respectively). G allele with DM also showed higher risk of CRC than G allele without DM (aOR 1.169, 95% CI 1.017). Significant higher CRC risk were showed in G allele with overweight, A allele with normal weight, and A allele with overweight as compared to G allele with overweight, aORs (95% CI) of 1.302 (1.143-1.485), 1.086(1.004-1.174), and 1.340 (1.217-1.475), respectively. Conclusions: The results indicated that A allele was a significantly associated between TCF7L2 rs11196172 polymorphism and the risk of CRC, with or without diabetes.