• Computers and Concrete
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• v.34 no.2
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• pp.247-265
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• 2024

Measuring the fracture toughness of concrete in laboratory settings is challenging due to various factors, such as complex sample preparation procedures, the requirement for precise instruments, potential sample failure, and the brittleness of the samples. Therefore, there is an urgent need to develop innovative and more effective tools to overcome these limitations. Supervised learning methods offer promising solutions. This study introduces seven machine learning algorithms for predicting concrete's effective fracture toughness (K-eff). The models were trained using 560 datasets obtained from the central straight notched Brazilian disc (CSNBD) test. The concrete samples used in the experiments contained micro silica and powdered stone, which are commonly used additives in the construction industry. The study considered six input parameters that affect concrete's K-eff, including concrete type, sample diameter, sample thickness, crack length, force, and angle of initial crack. All the algorithms demonstrated high accuracy on both the training and testing datasets, with R² values ranging from 0.9456 to 0.9999 and root mean squared error (RMSE) values ranging from 0.000004 to 0.009287. After evaluating their performance, the gated recurrent unit (GRU) algorithm showed the highest predictive accuracy. The ranking of the applied models, from highest to lowest performance in predicting the K-eff of concrete, was as follows: GRU, LSTM, RNN, SFL, ELM, LSSVM, and GEP. In conclusion, it is recommended to use supervised learning models, specifically GRU, for precise estimation of concrete's K-eff. This approach allows engineers to save significant time and costs associated with the CSNBD test. This research contributes to the field by introducing a reliable tool for accurately predicting the K-eff of concrete, enabling efficient decision-making in various engineering applications.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.2
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• pp.155-167
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• 2024

Distribution and logistics industries contribute some of the biggest GDP(gross domestic product) in South Korea and the number of related companies are quarter of the total number of industries in the country. The number of retail tech companies are quickly increased due to the acceleration of the online and untact shopping trend. Furthermore, major distribution and logistics companies try to achieve integrated data management with the fulfillment process. In contrast, small and medium distribution companies still lack of the capacity and ability to develop digital innovation and smartization. Therefore, in this paper, a deep learning-based demand forecasting & recommendation model is proposed to improve business competitiveness. The proposed model is developed based on real sales transaction data to predict future demand for each product. The proposed model consists of six deep learning models, which are MLP(multi-layers perception), CNN(convolution neural network), RNN(recurrent neural network), LSTM(long short term memory), Conv1D-BiLSTM(convolution-long short term memory) for demand forecasting and collaborative filtering for the recommendation. Each model provides the best prediction result for each product and recommendation model can recommend best sales product among companies own sales list as well as competitor's item list. The proposed demand forecasting model is expected to improve the competitiveness of the small and medium-sized distribution and logistics industry.

• Advances in nano research
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• v.17 no.2
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• pp.125-136
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• 2024

In the present research the durability and geotechnical properties of an expensive clayey soil stabilized by two different compositions of additives were investigated and compared. The first composition consisted of environmentally and ecofriendly materials: BOF steel slag ranging from 0-20% as well as rice husk ash (RHA) ranged 0-16%wt of dry soil. The other composition consisted of relatively new generation of materials including nanomaterials: nano-CaCO3 as well as nano-SiO2. Atterberg limits test, free swell percent test, swelling pressure test and unconfined compressive test were used to assess the stabilizers influences upon expansive soil geotechnical characteristics. Also, the recurrent wet-dry cycles test was exerted on experimental and non-experimental samples for estimating stabilizers effects on durability. According to the results, each of the BOF slag and RHA enhances the expansive soil properties individually, while combination of slag-RHA led to better improvement of the soil properties. Also, the composition of nano-CaCO3 and SiO2 dramatically improved the clay soil operation. The optimum values of slag+RHA were suggested as 20% slag+12% RHA to enhance percent of swelling, pressure of swelling in addition to UCS as much as 95%, 96%, and 370%, respectively. The optimum value for the second stabilizer in this study was found to be 2%nano-SiO2+2% nano-CaCO3 which led to 318% increase in UCS and 86% decrease in swelling pressure.

• Journal of Yeungnam Medical Science
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• v.4 no.2
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• pp.113-120
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• 1987

The effect of intravesical formalin instillation as a therapeutic modality for intractable bladder hemorrhage is well known. And despite clear evidence of therapeutic efficacy of intravesical cytotoxic drugs and/or BCG immunotherapy, there have been substantial recurrences during followup after transurethral resection for superficial bladder tumor. If formalin injected at the bed of superficial bladder tumor is able to coagulate and necrotize the tumor, it will be greatly helpful to the patients With recurrent bladder tumor developed during followup. Since this technique is applicable on outpatient basis, an economical as well as a psychological burden of the patients can be reduced considerably. The purpose of this study is to evaluate the effect of submucosal formalin injection on rat bladder wall, 36 healthy adult male Sprague-Dawley rats (weighing 350gm in average) were divided into 3 groups: In Group I (control group), 0.01ml of normal saline was injected submucosally at the left posterolateral wall of the bladder opened under intraperitoneal Nembutal anesthesia ; In Group II and III, 0.01 ml of 10% and 4% formalin, respectively, were administered at the same site as in the Group I, two rats in each group were sacrificed at day 1, 2, and 3, and week 1, 2 and 4 after injection, respectively. Gross and microscopic examination of the cystectomized specimen were done in each group. In the Group II, bladder stones were formed at week I, and in both the Group I and III, stones were seen at week 2 post injection. There was no significant difference III histologic findings of the bladder between the group II and III. Mucosal ulcer and/or prominent mucosal disruption was observed at 24 hours after injection in both Group II and III. Epithelial regeneration began at day 2, and was marked at day 3, and epithelial lining was almost normalized one week after injection. Subepithelial edema, telangiectasia and inflammatory reaction were prominent at 24 hours post formalin injection. Subepithelial edema persisted in moderate degree for 1 week. Telangiectasia and inflammatory reaction were noted for 4 weeks. Mild degree of these findings also appeared In the control group. Fibroblastic proliferation appeared at day 2 and persisted in moderate degree for 4 weeks. There has been no mortality or bladder perforation. These results suggest that clinical application of this technique is feasible for the selected cases of recurrent, solitary superficial bladder tumor. However, optimal dosage of formalin in relation to the size of the lesion remains to be investigated.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.1 no.1
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• pp.117-129
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• 1990

35 children(17 boys, 18 girls) with Recurrent Abdominal pain(RAP) without apparent organic causes, referrd from pediatric department of Seoul National University Children's Hospital were studied during 1988. 7. 1 ${\sim}$ 1989. 2. 28. The aims of this study are to examine clinical characteristics of the patients with RAP, to find possible factors influencing the onset and the course of the disorder, to evaluate the psychological status and the relationship with psychiatric diagnoses. The study subjects were compared with the age and sex matched control subjects on measures of social and school functioning, family-environment, behavior traits by CBCL and parent-environment rating scale. All patients and their mothers were interviewed by a child psychiatrist. The results were as follows ; 1) Abdominal pain was found to be more frequent when with a care taker, and related with traumatic life stresses such as separation from parents, death of family members. 2) Family members of the patients with RAP also had a high rate of a history of gastrointestinal dysfunctions with could not be attributed to organic etiologies. 3) Among 35 patients with RAP, 16 were diagnosed as psychiatric disorders. They were adjustment disorders (4), overanxious disorders (4), depression (2), tic disorders (2), attention deficit disorders (2), separation anxiety disorders (1), enuresis (1). 4) On CBCL, the patients with RAP were more internalized, socially less competent and less active compared with the control subjects. 5) According to the parent-environment rating scale, the patients with RAP had more conflicts with their parents about control issues. Family members of the patients with RAP were socially less competent and less abjustable. The parents of the patients with RAP were more affectionate and spent more time with their children but they were unfair and vague on instruction and discipline.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.3
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• pp.201-208
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• 2008

Purpose: We aimed to assess the role of positron emission tomography using fluorodeoxyglucose (FDG-PET) in the diagnosis of recurrence or the assessment of therapeutic response in cervical and ovarian cancer patients through making a comparison between FDG-PET, abdominal computed tomography (CT) and serum tumor marker. Materials and methods: We included 103 cases (67 patients) performed FDG-PET and abdominal CT. There were 42 cervical cancers and 61 ovarian cancers. We retrospectively reviewed the interpretations of PET and CT images as well as the level of tumor marker. We calculated their sensitivity, specificity, positive predictive value and negative predictive value for these three modalities. And then we analyzed the differences between these three modalities. Results: Tumor recurrences were diagnosed in 37 cases (11 cervical cancers and 26 ovarian cancers). For PET, CT and tumor marker, in cervical cancer group, sensitivity was 100% (11/11), 54.5% (6/11) and 81.1% (9/11), respectively. And specificity was 93.6% (29/31), 93.6% (29/31) and 100% (31/31). In ovarian cancer group, sensitivity was 96.2% (25/26), 84.6% (22/26) and 80.8% (21/26), and specificity was 94.3% (33/35), 94.3% (33/35), 94.3% (33/35), PET was highly sensitive to detect the intraperitoneal and extraperitoneal metastasis with the help of the CT images to localize the lesions. However, CT had limitations in differentiation of the recurrent tumor from benign fibrotic tissue, identification of viable tumors at the interface of tissues, and detecting extraperitoneal lesions. Conclusion: FDG-PET can be an essential modality to detect the recurrent or residual tumors in gynecologic cancer patients because of its great field of the application and high sensitivity.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.3
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• pp.285-293
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• 2017

Globally, 1.3 million people develop colon cancer every year, and 600,000 people die each year it. In Korea, colorectal carcinoma was associated with the highest death rate, accounting for 8,380 people, among solid cancers in 2015. Among the various methods for the diagnosis and study of colorectal carcinoma, the results obtained by cytogenetic and molecular genetic methods were compared. Detection rate was 47% in 18q, 40% in 17p, 27% in 22q, and 17% in 10q via CGH; detection rate was 57% in D18S59, 50% in D18S68, 50% in TP53CA, 47% in D18S6940% in D22S274, 37% in D22S283, 27% in D10S187, and 23% in D10S541 with LOH. Microsatellite marker matching rates were 100% in D22S274, 100% in D22S283, 100% in D10S186, 100% in D10S187, 100% in D10S541, 93% in D18S69, 93% in D18S68, 92% in TP53CA, and 89% in D18S59. The agreement rate between the two methods was 94.4% based on positive results using CGH. Based on the advantages of CGH, which was the ability to obtain information regarding the entire tumor genome at once, this experiment could identify the region with significant deletion using CGH and the more limited region LOH, with a completely different approach. LOH in the recurrent high-risk group, 18q21, was helpful in the selection of treatment modalities and in prognostic estimation as well as making the most appropriate decision for treatment. Therefore, it is suggested that LOH with surgical site tissues could be one of the treatment methods for recurrent high-risk group among patients with colorectal carcinoma.

• Childhood Kidney Diseases
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• v.8 no.2
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• pp.223-228
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• 2004

Purpose and Methods: Urinary tract infection(UTI) is one of the most important diseases of childhood, especially for young infants. To characterize the patients diagnosed with febrile UTI in their first 6 months of life and to explore the risk factors of recurrent UTI, a retrospective study was performed. Results: Among the 90 patients studied, 77 were boys(86%). First episodes of UTI were diagnosed at the age of $2.5{\pm}1.4$ months. These patients underwent ultrasonographic evaluation of urinary tract(n=90) and voiding cystourethrography(n=81) where 53 and 35 studies showed abnormal findings respectively, and a total of 45 cases of urinary tract anomaly including vesicoureteral reflux(VUR, n=35) were diagnosed. Normal findings on ultrasonography indicated decreased risk of VUR in boys of 1-3 months of age(n=30). 53 patients were followed up more than 6 months and 45 episodes of subsequent UTI developed in 29 patients during the first 6-month period. Patients with relapse were older than patients without relapse at the diagnosis of first UTI, but other clinical parameters including abnormal findings on the imaging studies and prophylactic antibiotics prescription were not different between the two groups. Conclusion: UTI in early infancy occurred mainly in male infants and half of the patients had structural anomalies. USG was of clinical value in detecting anomalies requiring surgical intervention, and to rule out high grade VUR in 1-3 months old boys. Results of the imaging study or prophylactic antibiotics could not modify the risk of recurrent UTI. (J Korean Soc Pediatr Nephrol 2004;8:223-228)

• Journal of Chest Surgery
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• v.42 no.3
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• pp.350-354
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• 2009

Background: Complicated pleural space occupying lesions (SOL) have been treated by thoracentesis, closed thoracotomy drainage (CTD) or surgical intervention with using a video thoracosocpe or open thoracotomy depending on the extent of the disease. With the development of video assisted thoracoscopic surgery (VATS), VATS pleural adhesiolysis and decortication have revealed good results as compared to those for open thorcotomy. To assess the effectiveness of VATS pleural adhesiolysis and decortication, we retrospectively analyzed the medical record and radiologic findings of the patients with complicated pleural SOL and who were treated by this surgery. Material and Method: From May 1996 to April 2006, 64 patients (mean age: 41.8 years) with complicated pleural SOL underwent 65 VATS. To analyze the surgical outcome, we classified the postoperative findings on the simple chest X-rays into 4 classes as Class I: no or minimal pleural lesion, Class II: blunting of the cardiophrenic angle and mild pleural thickening, Class III: an elevated diaphgram or persistent lung collapse and Class IV: complicated or recurrent effusion. Result: Before VATS, the patients underwent the diagnostic or therapeutic procedures: single or repeat diagnostic tapping for 41, thoracoscotomy drainage for 11, pigtail catheter drainage for 10 and intrapleural fibrinolytics for 10. The mean duration between the onset of symptom and surgery was 18.4 days. There was neither mortality nor severe complications. The surgical outcomes were class 1 for 28, class 2 for 13, class 3 for 19 and class 4 for 5. There were statistically significant differences between the symptom duration and the classes, and between the operation time and the classes. Conclusion: VATS pleural adhesiolysis and decortication are effective, safe treatments for managing complicated pleural SOL, and an earlier operation is needed for obtaining a better surgical outcome.

• The Korean Journal of Nuclear Medicine
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• v.33 no.6
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• pp.493-501
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• 1999

Purpose: We conducted a comparative study to evaluate the diagnostic values of T1-201, Tc-99m MIBI and I-131 scans in the follow-up assessment after ablative I-131 therapy in differentiated thyroid cancer. Materials and Methods: The study population consisted of 20 patients who underwent surgical removal of thyroid cancer and ablative radioactive iodine therapy, and followed by one or mote times of I-131 retreatments (33 cases). In all patients, T1-201, Tc-99m MIBI, diagnostic and therapeutic I-131 scans were performed and the results were analyzed retrospectively. Also serum thyroglobulin levels were measured in all patients. The final diagnosis of recurrent or metastatic thyroid cancer was determined by clinical, biochemical, radiologic and/or biopsy findings. Results: Positive rates (PR) of Tc-99m MIBI, T1-201, diagnostic and therapeutic I-131 scans in detecting malignant thyroid tissue lesions were 70% (19/27), 54% (15/28), 35% (17/48) and 63% (30/48), respectively. The PR in the group of 20 cases (28 lesions) who underwent concomitant T1-201 and I-131 scans were in the order of therapeutic 131 scan 71%, T1-201 scan 54% and diagnostic I-131 scan 36%. There was no statistically significant difference between T1-201 and diagnostic I-131 scans (p>0.05). In the group of 20 cases (27 lesions) who underwent concomitant Tc-99m MIBI and I-131 scans, the PR were in the order of Tc-99m MIBI scan 70%, I-131 therapeutic scan 52% and I-131 diagnostic scan 33%. The PR of Tc-99m MIBI was significantly higher than that of diagnostic I-131 scan (p<0.05). Conclusion: Tc-99m MIBI scan is superior to diagnostic I-131 scan in detecting recurrent or metastatic thyroid cancer following ablation therapy in patients with differentiated thyroid cancer. T1-201 scan did not showed significantly higher positive rate than diagnostic I-131 scan. Instead of diagnostic I-131 scan before the I-131 retreatment, Tc-99m MIBI scan without discontinuing thyroid hormone replacement would be a prudent and effective approach in the management of these patients.