• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.1
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• pp.107-122
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• 2015

Many defensive mechanisms have been evolved as new attack methods are developed. However, APT attacks using e-mail are still hard to detect and prevent. Recently, many organizations in the government sector or private sector have been hacked by malicious e-mail based APT attacks. In this paper, first, we built hacking e-mail database based on the real e-mail data which were used in attacks on the Korean government organizations in recent years. Then, we extracted features from the hacking e-mails for profiling them. We design a case vector that can describe the specific characteristics of hacking e-mails well. Finally, based on case based reasoning, we made an algorithm for retrieving the most similar case from the hacking e-mail database when a new hacking e-mail is found. As a result, hacking e-mails have common characteristics in several features such as geo-location information, and these features can be used for classifying benign e-mails and malicious e-mails. Furthermore, this proposed case based reasoning algorithm can be useful for making a decision to analyze suspicious e-mails.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.19 no.4
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• pp.236-242
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• 2016

Purpose: The aim of this study was to investigate the clinical features and extraintestinal manifestations (EIMs) of Crohn disease (CD) in Korean pediatric patients. Methods: The medical records of 73 children diagnosed with CD were retrospectively reviewed. Data regarding baseline demographic and clinical characteristics, including CD phenotype at diagnosis based on the Montreal classification, and clinical features and course of EIMs were investigated. Results: Fifty-two (71.2%) of the patients were males. The mean age of the patients was 12.5 years. The mean follow-up period was 3.4 years. The disease location was ileal in 3 (4.1%) of the patients, colonic in 13 (17.8%), ileocolonic in 56 (76.7%). The clinical behavior was inflammatory in 62 (84.9%) of the patients, stricturing in 8 (11.0%), and penetrating in 3 (4.1%). Perianal abscesses or fistulas were found in 37 (50.7%) of the patients. EIMs observed during the study period were anal skin tag in 25 patients (34.2%), hypertransaminasemia in 20 (27.4%), peripheral arthritis in 2 (2.7%), erythema nodosum in 2 (2.7%), vulvitis in 1 (1.4%), uveitis in 1 (1.4%), and pulmonary thromboembolism in 1 (1.4%). Conclusion: Perianal diseases and manifestations were present in more than half of Korean pediatric CD patients at diagnosis. Inspection of the anus should be mandatory in Korean children with suspicious CD, as perianal fistulas, abscesses, and anal skin tags may be the first clue to the diagnosis of CD.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7457-7461
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• 2015

Some thyroid cancer patients undergone insufficient tumor removal in the primary surgery in China. our aim is to evaluate the impact of dissection of the recurrent laryngeal nerve during a salvage thyroid cancer operation in these patients to prevent nerve injury. Clinical data of 49 enrolled patients who received a salvage thyroid operation were retrospectively reviewed. Primary pathology was thyroid papillary cancer. The initial procedure performed included nodulectomy (20 patients), partial thyroidectomy (19 patients) and subtotal thyroidectomy (10 patients). The effect of dissection and protection of the recurrent laryngeal nerve and the mechanism of nerve injury were studied. The cervical courses of the recurrent laryngeal nerves were successfully dissected in all cases. Nerves were adherent to or involved by scars in 22 cases. Three were ligated near the place where the nerve entered the larynx, while another three were cut near the intersection of inferior thyroid artery with the recurrent laryngeal nerve. Light hoarseness occurred to four patients without a preoperative voice change. In conclusion, accurate primary diagnosis allows for a sufficient primary operation to be performed, avoiding insufficient tumor removal that requires a secondary surgery. The most important cause of nerve damage resulted from not identifying the recurrent laryngeal nerve during first surgery, and meticulous dissection during salvage surgery was the most efficient method to avoid nerve damage.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.4
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• pp.1831-1835
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• 2014

Background: To investigate the relationship between extracellular matrix parameters and texture of prostatic lesions evaluated by transrectal real-time tissue elastography (TRTE). Methods: 120 patients suspicious for prostate cancer underwent TRTE. Targeted biopsies were carried out after 12-core systematic biopsy. Epithelia were stained with hematoxylin-eosin, and Victoria blue and Ponceau S were used to stain elastic-collagen fibers, and picric acid-sirius red for visualization of collagen type I (Col1) and III (Col3). Smooth muscles were visualized by immunohistochemistry. All image analyses were performed in a blind manner using Image Pro Plus 6.0, and the area ratios of epithelium, elastic fibers, collagen fibers and Col1/Col3 were determined. Results: 42 patients with typical elastograms were included in the final data analysis. Significant differences were detected between the benign and malignant groups in the area ratios of epithelium (P = 0.01), smooth muscles and Col1/Col3 (P = 0.04, P = 0.02, respectively). There were no significant differences in the area ratios of epithelium, smooth muscle and elastic fibers between the stiff and soft lesion groups. The area ratio of Col1 was ($0.05{\pm}0.03$) in the stiff group, and ($0.02{\pm}0.01$) in the soft group (P= 0.00). However, the area ratio of Col3 was ($0.03{\pm}0.02$) in the stiff group, and ($0.05{\pm}0.04$) in the soft group (P = 0.16). Col1/Col3 in the stiff group ($1.99{\pm}1.59$) was greater than in the soft group ($0.71{\pm}0.64$) (P = 0.01). Conclusions: Tissue hardness of prostatic tumors was mainly dependent on the Col1 content, Col1/Col3 being higher in malignant than in benign lesions, so the prostate tissue texture can be used as a target for distinguishing between the two with TRTE.

• Archives of Plastic Surgery
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• v.33 no.2
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• pp.233-236
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• 2006

Merkel cell carcinoma is rare skin malignancy originated from epidermal mechanoreceptor of neural origin. The tumor usually affects older individuals at sun exposed area such as head, neck and extremity. Subclinical involvement of regional lymph node is reported frequently at the time of initial treatment. Thus even asymptomatic patients who present with clinically localized tumor should undergo evaluation with computed tomography and lymphangiography. Positron emission tomography(PET) scans can imaging the metabolic difference of malignant tumors. Increased glucose uptake of malignant tumor cells are detected by PET scanner. PET scans can provide qualitative and quantitative informations about systemic metastasis of tumors. Although there are no data that define the efficacy of PET scans in the initial diagnostic evaluation of head and neck cancer, they could be considered. Current standards of treatment of Merkel cell carcinoma is wide surgical excision and regional lymphadenectomy if there are suspicious lymph nodes. The author reported a patient with Merkel cell carcinoma of cheek. Wide surgical excision and postoperative PET/CT was done for evaluation of regional lymph node and distant metastasis. There were two hot-uptakes in patient's neck, so they were considered as metastatic node, but finally they were proved to be tuberculosis lymphadenitis after excision.

• The Korean Journal of Nuclear Medicine
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• v.3 no.1
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• pp.33-39
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• 1969

The conventional triolen absorption test has its defect in that the stool collection was cumbersome, time and energy-wasting. In the present study, the triolen absorption test was carried out using double tracer technique with $^{125}I-triolen\;and\;^{51}Cr_2O_3$ to determine if it can overcome the defect of the conventional method also with satisfactory results. Following were the results: 1. The clinical significance of this double tracer method was essentially the same with that previously done by radioactive. triolen alone. With the fractional fecal samples, the equation, y=0.626x+2.010 was substantiated, hence, this method appears to be clinically valuable if the appropriate correction is applied. With the mixed fecal samples, the equation y=0.642x+1.468 was substantiated (p<0.005) which appears to be also clinically valuable. When these two data were compared, the equation y=0.975x+0.090 (P<0.05) was substantiated, hence, $x{\fallingdotseq}y$. 2. The normal ranges of the fecal triolen excretion rate in this double tracer method were $3.46{\pm}1.69%$, namely, less than 6.9%. 3. The samplings were done from the first to third defecation in cases of clinically normal, and from the first to second defecation in cases of diarrhea or malabsorption. 4. The intestinal malabsorption of triolen was not observed in whom the triolen absorption was supposed to be clinically normal, however. a good number of suspicious malabsorptive cases showed the normal values.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.4
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• pp.151-162
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• 2022

Recently, the forests in Korea have accumulated damage due to continuous forest disasters, and the need for technologies to monitor forest managements is being issued. The size of the affected area is large terrain, technologies using drones, artificial intelligence, and big data are being studied. In this study, a standard dataset were conducted to develop an algorithm that automatically detects suspicious trees damaged by forest pests using deep learning and drones. Experiments using the YOLO model among object detection algorithm models, the YOLOv4-P7 model showed the highest recall rate of 69.69% and precision of 69.15%. It was confirmed that YOLOv4-P7 should be used as an automatic detection algorithm model for trees suspected of being damaged by forest pests, considering the detection target is an ortho-image with a large image size.

• Korean Journal of Radiology
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• v.22 no.3
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• pp.297-307
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• 2021

Objective: To compare the performance of simulated abbreviated breast MRI (AB-MRI) and full diagnostic (FD)-MRI in distinguishing between benign and malignant lesions detected by MRI and investigate the features of discrepant lesions of the two protocols. Materials and Methods: An AB-MRI set with single first postcontrast images was retrospectively obtained from an FD-MRI cohort of 111 lesions (34 malignant, 77 benign) detected by contralateral breast MRI in 111 women (mean age, 49.8. ± 9.8; range, 28-75 years) with recently diagnosed breast cancer. Five blinded readers independently classified the likelihood of malignancy using Breast Imaging Reporting and Data System assessments. McNemar tests and area under the receiver operating characteristic curve (AUC) analyses were performed. The imaging and pathologic features of the discrepant lesions of the two protocols were analyzed. Results: The sensitivity of AB-MRI for lesion characterization tended to be lower than that of FD-MRI for all readers (58.8-82.4% vs. 79.4-100%), although the findings of only two readers were significantly different (p < 0.05). The specificity of AB-MRI for lesion characterization was higher than that of FD-MRI for 80% of readers (39.0-74.0% vs. 19.5-45.5%, p ≤ 0.001). The AUC of AB-MRI was comparable to that of FD-MRI for all readers (p > 0.05). Fifteen percent (5/34) of the cancers were false-negatives on AB-MRI. More suspicious margins or internal enhancement on the delayed phase images were related to the discrepancies. Conclusion: The overall performance of AB-MRI was similar to that of FD-MRI in distinguishing between benign and malignant lesions. AB-MRI showed lower sensitivity and higher specificity than FD-MRI, as 15% of the cancers were misclassified compared to FD-MRI.

• Korean Journal of Radiology
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• v.21 no.1
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• pp.108-116
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• 2020

Objective: To investigate the concordance of three international guidelines: the Korean Thyroid Association/Korean Society of Thyroid Radiology, American Thyroid Association, and American College of Radiology for thyroid nodules classified by ultrasonography (US) and the diagnostic performance of simulated size criteria for malignant biopsies. Materials and Methods: A total of 2586 thyroid nodules (≥ 1 cm) were collected from two multicenter study datasets. The classifications of the thyroid nodules were based on three different guidelines according to US categories for malignancy risk, and the concordance rate between the different guidelines was calculated for the classified nodules. In addition, the diagnostic performance of criteria related to four different simulated biopsy sizes was evaluated. Results: The concordance rate of nodules classified as high- or intermediate-suspicion was high (84.1-100%), but low-suspicion or mildly-suspicious nodules exhibited relatively low concordance (63.8-83.8%) between the three guidelines. The differences in sensitivity, specificity, and accuracy between the guidelines were 0.7-19.8%, 0-40.9%, and 0.1-30.5%, respectively, when the original biopsy criteria were applied. The differences decreased to 0-5.9%, 0-10.9%, and 0.1-8.2%, respectively, when simulated, similar biopsy size criteria were applied. The unnecessary biopsy rate calculated with the original criteria (0-33.8%), decreased with the simulated biopsy size criteria (0-8.7%). Conclusion: We found a high concordance between the three guidelines for high- or intermediate-suspicion nodules, and the diagnostic performance of the biopsy criteria was approximately equivalent for each simulated size criterion. The difference in diagnostic performance between the three guidelines is mostly influenced by the various size thresholds for biopsies.

• Korean Journal of Head & Neck Oncology
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• v.40 no.1
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• pp.1-5
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• 2024

The Bethesda System for Reporting Thyroid Cytopathology (TBSRCT) is crucial for cytopathologists to use a standardized, category-based reporting system for thyroid fine needle aspirations and is effective for clear communication with the referring physicians. The new Bethesda System for Reporting Thyroid Cytopathology, the third edition in 2023, provides several key updates. The most important update is the assignment of only single name for each of the six diagnostic categories: (I) nondiagnostic; (II) benign; (III) atypia of undetermined significance; (IV) follicular neoplasm; (V) suspicious for malignancy; and (VI) malignant. An implied risk of malignancy (ROM) for each of six categories has been updated based on extensively published data since the second edition of TBSRTC in 2017 and offers both an average ROM for each category and the expected range of cancer risk. Estimated final ROM after excluding "Noninvasive Follicular Thyroid Neoplasm with Papillary Like Nuclear Features (NIFTP)" for each of six categories has been updated based on the reported mean decreases in the ROM if excluding NIFTP. For atypia of undetermined significance (AUS) category, the subcategorization is simplified and more formalized into 2 subgroups, AUS-nuclear atypia or AUS-other, based on the implied ROM and molecular profiling. For the pediatric thyroid disease, pediatric ROMs and management algorithms are newly added for the same six reporting categories for this age group. New or revised disease nomenclatures including high-grade follicular-derived carcinoma has been updated according to the recently published 2022 World Health Organization Classification of Thyroid Neoplasms. Brand new two chapters are added including clinical perspectives and imaging studies (Chap. 13) and the use of molecular and other ancillary tests (Chap. 14). The atlas is updated with new images to illustrate more effectively for new disease entity and diagnostic criteria.