• Journal of Food Hygiene and Safety
• /
• v.14 no.3
• /
• pp.293-304
• /
• 1999

The purpose of this study was to evaluate the microbiological quality, and to assure the hygienic safety of the food production in the university food service facility located in Seoul in accordance with the Hazard Analysis Critical Control Point(HACCP) concepts. In the hygienic state assessment of kitchen, it has revealed that it was very important to remove water from the kitchen floor and to establish standard method for disinfection of cooking utensils. And foodservice workers were required to have training program for the safe handling of food and utensils since they did treat food without hygienic gloves. The kitchen layout had to be improved because the near distance of table with heating unit and shelf might cause the growth of microorganisms when prepared food was kept on the shelf. In terms of the timetemperature measurement and microbiological quality assessment during each of the food production phases, most of sengchae (raw vegetable dish) and namul (cooked vegetable dish) were treated within danger zone for food safeness ($5~60^{\circ}C$). It has shown that the microbiological quality of raw materials was very much inferior at the time of receiving based on the TPC($10^{5}~10^{7}$), coliform($10^{3}~1O^{6}$), which was not acceptable level(TPC:$10^{6}$, coliform:$10^{3}$) suggested by Solberg. Microbiological growth has increased in the both of sengchae and namul considerably during most of food production phase. Therefore, it is extremely important to reduce holding and serving time and to avoid treating food within the danger zone for food safeness. In addition, the prevention of cross-contamination during mixing the ingredients with improper equipments and with insanitary treatments by workers was also important to keep the food safety in this speciqic university foodservice facility.

• Journal of Periodontal and Implant Science
• /
• v.27 no.4
• /
• pp.819-828
• /
• 1997

The purpose of this study was to evaluate the abrasion-resistance of root surface after NaF iontophoresis, Nd:YAG laser irradiation and combined treatment 50 anterior teeth with flat interproximal root surface that had been extracted due to periodontal destruction were selected. All teeth were treated by the same procedure as conventional periodontal root treatment, such as scaling and root planing, root conditioning with tetracycline HCI(lOOmg/ml, 5min). The pre-treatment weight of each tooth was measured by a dial scale(SHIMADEU Co, LIBROR EB-220HU, capacity 220.000 g, Japan). All teeth were divided into 5 groups as follows: Nd:YAG laser irradiation(group 1, 1 W, 100 mJ, 10Hz, fiberoptic-root surface distance=5mm, $10\;sec.{\times}6times$, EL.EN.EN060, Italy): NaF iontophoresis(group 2, $150{\mu}A$, 4 min}: Nd:YAG laser irradiation following NaF iontophoresis(group 3): NaF iontophoresis following Nd:YAG laser irradiation(group 4): No treatment(control group). Electric toothbrushing (Oral-B, Brown Co, Germany) was conducted during 1 hour($lO\;min.{\times}6\;times$). Subsequently post-treatment weight was remeasured by the same method as pre-treatment weight measurement. The difference of abrasion rate among all groups was statistically analyzed by ANOVA(SAS program). Following results were obtained: 1. The abrasion rate was significantly lower in Nd:YAG laser irradiation group than NaF iontophoresis group(p < 0.001). 2. The abrasion rate was significantly lower in combined groups of Nd:YAG laser irradiation and NaF iontophoresis than either Nd:YAG laser irradiation group or NaF iontophoresis group(p < 0.001). 3. There was no significant difference in abrasion rate according to application order in the combined groups(p > 0.05). 4. The abrasion rate was significantly lower in all experimental groups than control group(p < 0.001). The results suggest that combined treatment of Nd:YAG laser irradiation and NaF iontophoresis on exposed root surface after periodontal therapy can enhance the abrasion-resistance of root surface and may inhibit the root caries development.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.34 no.1
• /
• pp.31-37
• /
• 2014

The aim of this study was the non-destructive evaluation of bloody eggs using VIS/NIR spectroscopy. The bloody egg samples used to develop the sorting mode were produced by injecting chicken blood into the edges of egg yolks. Blood amounts of 0.1, 0.7, 0.04, and 0.01 mL were used for the bloody egg samples. The wavelength range for the VIS/NIR spectroscopy was 471 to 1154 nm, and the spectral resolution was 1.5nm. For the measurement system, the position of the light source was set to $30^{\circ}$, and the distance between the light source and samples was set to 100 mm. The minimum exposure time of the light source was set to 30 ms to ensure the fast sorting of bloody eggs and prevent heating damage of the egg samples. Partial least squares-discriminant analysis (PLS-DA) was used for the spectral data obtained from VIS/NIR spectroscopy. The classification accuracies of the sorting models developed with blood samples of 0.1, 0.07, 0.04, and 0.01 mL were 97.9%, 98.9%, 94.8%, and 86.45%, respectively. In this study, a novel nondestructive sorting technique was developed to detect bloody brown eggs using spectral data obtained from VIS/NIR spectroscopy.

• The KIPS Transactions:PartD
• /
• v.13D no.5 s.108
• /
• pp.633-640
• /
• 2006

Spatial clustering, which groups similar objects based on their distance, connectivity, or their relative density in space, is an important component of spatial data mining. Density-based and grid-based clustering are two main clustering approaches. The former is famous for its capability of discovering clusters of various shapes and eliminating noises, while the latter is well known for its high speed. Clustering large data sets has always been a serious challenge for clustering algorithms, because huge data set would make the clustering process extremely costly. In this paper, we propose an enhanced Density-Grid based Clustering algorithm for Large spatial database by setting a default number of intervals and removing the outliers effectively with the help of a proper measurement to identify areas of high density in the input data space. We use a density threshold DT to recognize dense cells before neighbor dense cells are combined to form clusters. When proposed algorithm is performed on large dataset, a proper granularity of each dimension in data space and a density threshold for recognizing dense areas can improve the performance of this algorithm. We combine grid-based and density-based methods together to not only increase the efficiency but also find clusters with arbitrary shape. Synthetic datasets are used for experimental evaluation which shows that proposed method has high performance and accuracy in the experiments.

• Journal of Radiation Industry
• /
• v.9 no.2
• /
• pp.69-75
• /
• 2015

Purpose: The gonad shielding is used to minimize the impact of the exposure to gonads when Abdomen, Pevis and Hip X-ray inspections are conducted on radiation impressionable pediatric patients. By the way, the gonad is palpable difficult and impossible to check visually because it's a sensitive area, so tests are conducted with the approximate location of shielding, thereby appearing problems of not shielding gonads accurately. Accordingly, this study produced shields by age and gender of pediatric patients and studied the method of positioning shields with ASIS as a reference point without palpable sensitive areas, and tried to evaluate its usability. Materials and methods: The study surveyed 30 pediatric patients by gender and age, who came and got inspected in Department of Radiology, our hospital from February 2012 to January 2014 and obtained the value of tolerance by measuring the average size of the pelvis using the distance measurement function of Infinitt Piview with the images stored in the PACS and producing shields by age and gender of pediatric patients and specifying the areas at random for the comparative analysis of pre- and post-using. It calculated the technology statistics($mean{\pm}SD$) with the value of tolerance measured the length using SPSS 12.0 statistical program. Results: As for boys, differences in the tolerance range of pre- and post-using shields were 2.69 mm in case of 1 year old, 2.58 mm in 2 years, 2.37 mm in 3 years, 2.815 mm in 4~5 years, 2.043 mm in 7~10 years, and as for girls, 1.92 mm in 1~2 years, 1.75 mm in 3~4 years, 2.52 mm in 5~6 years and 1.93 mm in 7~10. After analyzing the pre- and post-using shields for all of boys and girls, there were statistically significant differences(P<0.050). Conclusions: It is considered that we can minimize the exposure to gonads and get a better video for diagnosis in testing high biological impressionable pediatric, if we use shields correctly with ASIS as a reference point considering its shape and size by age and gender in Abdomen, Pevis and Hip X-ray inspections.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.20 no.6
• /
• pp.760-767
• /
• 2014

An experimental study is carried out to investigate the effect of jet stream in the gab of rectangular cylinders with different length in a parallel arrangement by using PIV method in a circulating water channel. The height(h) of the rectangular cylinder and the gap between the cylinder is 10mm, and the width(B) which is 300mm. The length of the model for flow direction was applied to 30mm, 60mm, 90mm & 120mm, The aspect ratio of a model on the basis of height(H=30mm) is 1, 2, 3 and 4. Reynolds number $Re=1.4{\times}10^4$, $Re=2.0{\times}10^4$, $Re=2.9{\times}10^4$ based on the height(H) of model for the distance of tidal distributions as of water depth have been applied during the whole experiments. The measurement area was set to 5H rear of the cylinder. As a result, Vortex size in the wake area were increased as velocity increased. and high aspect ratio increased through-flow velocity component in the near wake. Velocity deficit increased highly after near-wake area and low aspect ratio.

• Ecology and Resilient Infrastructure
• /
• v.8 no.1
• /
• pp.22-31
• /
• 2021

Surface image velocimetry (SIV) is a noncontact velocimetry technique based on images. Recently, studies have been conducted on surface velocity measurements using drones to measure a wide range of velocities and discharges. However, when measuring the surface velocity using a drone, reference points must be included in the image for image correction and the calculation of the ground sample distance, which limits the flight altitude and shooting area of the drone. A technique for calculating the surface velocity that does not require reference points must be developed to maximize spatial freedom, which is the advantage of velocity measurements using drone images. In this study, a technique for calculating the surface velocity that uses only the drone position and the specifications of the drone-mounted camera, without reference points, was developed. To verify the developed surface velocity calculation technique, surface velocities were calculated at the Andong River Experiment Center and then measured with a FlowTracker. The surface velocities measured by conventional SIV using reference points and those calculated by the developed SIV method without reference points were compared. The results confirmed an average difference of approximately 4.70% from the velocity obtained by the conventional SIV and approximately 4.60% from the velocity measured by FlowTracker. The proposed technique can accurately measure the surface velocity using a drone regardless of the flight altitude, shooting area, and analysis area.

• The korean journal of orthodontics
• /
• v.54 no.1
• /
• pp.48-58
• /
• 2024

Objective: To quantify the effects of midline-related landmark identification on midline deviation measurements in posteroanterior (PA) cephalograms using a cascaded convolutional neural network (CNN). Methods: A total of 2,903 PA cephalogram images obtained from 9 university hospitals were divided into training, internal validation, and test sets (n = 2,150, 376, and 377). As the gold standard, 2 orthodontic professors marked the bilateral landmarks, including the frontozygomatic suture point and latero-orbitale (LO), and the midline landmarks, including the crista galli, anterior nasal spine (ANS), upper dental midpoint (UDM), lower dental midpoint (LDM), and menton (Me). For the test, Examiner-1 and Examiner-2 (3-year and 1-year orthodontic residents) and the Cascaded-CNN models marked the landmarks. After point-to-point errors of landmark identification, the successful detection rate (SDR) and distance and direction of the midline landmark deviation from the midsagittal line (ANS-mid, UDM-mid, LDM-mid, and Me-mid) were measured, and statistical analysis was performed. Results: The cascaded-CNN algorithm showed a clinically acceptable level of point-to-point error (1.26 mm vs. 1.57 mm in Examiner-1 and 1.75 mm in Examiner-2). The average SDR within the 2 mm range was 83.2%, with high accuracy at the LO (right, 96.9%; left, 97.1%), and UDM (96.9%). The absolute measurement errors were less than 1 mm for ANS-mid, UDM-mid, and LDM-mid compared with the gold standard. Conclusions: The cascaded-CNN model may be considered an effective tool for the auto-identification of midline landmarks and quantification of midline deviation in PA cephalograms of adult patients, regardless of variations in the image acquisition method.

• The korean journal of orthodontics
• /
• v.30 no.5 s.82
• /
• pp.565-578
• /
• 2000

The aim of this study was development of the Straight-Wire Appliance(SWA) suitable lot the treatment or Korean. To accomplish the object of this study, Korean adult with normal occlusion were selected with following criteria : 1) no functional abnormality in the craniofacial area, 2) good dental arch form and posterior occlusal relationship, 3) Angle Class I occlusal relationship, 4) no experience of orthodontic, nor prosthodontic treatment, especially, no dental treatment on labial and buccal surfaces of teeth, 5) good racial profile. Impression were taken for upper and lower dental arches or the selected normal occlusion samples and the orthodontic dental stone models were fabricated. 5 well-trained orthodontists had examined the acquired dental stone models to select study samples which satisfy the Six keys to optimal occlusion of Andrews. 155 pairs of dental stone models (92 pairs of Male, 63 of Female) were finally selected. 3 dimensional digitization were performed with the Coordinate Measuring Machine(CMM, MPC802, WEGU-Messtechnik, Germany) and measuring of Angulation, Inclination, In-and-Out, Molar offset angle and Arch form were accomplished with a measuring software to achieve data for the development of SWA. Before the measurement, error study was performed on the 3 dimensional digitization with CMM, and the analysis of reliability of computerized measuring method adapted in this study and conventional manual method Presented by Andrews was performed. Results of this study were as to)lows : 1. Equi-distance digitization with mesh size 0.25 mm, 0.5 mm and 1.0 mm were acceptable in 3 dimensional digitization of dental stone model with the CMM, and the digitization with 1.0 mm mesh size was recommendable in terms of efficiency. 2. Computerized measuring method with 3 dimensional digitization was more reliable than manual measuring method of Andrews. 3. Data were collected for the development of SWA suitable for the morphological characteristics of Korean with the computerized measuring method with 3 dimensional digitization.

• Journal of Intelligence and Information Systems
• /
• v.23 no.1
• /
• pp.47-67
• /
• 2017

Steel plate faults is one of important factors to affect the quality and price of the steel plates. So far many steelmakers generally have used visual inspection method that could be based on an inspector's intuition or experience. Specifically, the inspector checks the steel plate faults by looking the surface of the steel plates. However, the accuracy of this method is critically low that it can cause errors above 30% in judgment. Therefore, accurate steel plate faults diagnosis system has been continuously required in the industry. In order to meet the needs, this study proposed a new steel plate faults diagnosis system using Simultaneous MTS (S-MTS), which is an advanced Mahalanobis Taguchi System (MTS) algorithm, to classify various surface defects of the steel plates. MTS has generally been used to solve binary classification problems in various fields, but MTS was not used for multiclass classification due to its low accuracy. The reason is that only one mahalanobis space is established in the MTS. In contrast, S-MTS is suitable for multi-class classification. That is, S-MTS establishes individual mahalanobis space for each class. 'Simultaneous' implies comparing mahalanobis distances at the same time. The proposed steel plate faults diagnosis system was developed in four main stages. In the first stage, after various reference groups and related variables are defined, data of the steel plate faults is collected and used to establish the individual mahalanobis space per the reference groups and construct the full measurement scale. In the second stage, the mahalanobis distances of test groups is calculated based on the established mahalanobis spaces of the reference groups. Then, appropriateness of the spaces is verified by examining the separability of the mahalanobis diatances. In the third stage, orthogonal arrays and Signal-to-Noise (SN) ratio of dynamic type are applied for variable optimization. Also, Overall SN ratio gain is derived from the SN ratio and SN ratio gain. If the derived overall SN ratio gain is negative, it means that the variable should be removed. However, the variable with the positive gain may be considered as worth keeping. Finally, in the fourth stage, the measurement scale that is composed of selected useful variables is reconstructed. Next, an experimental test should be implemented to verify the ability of multi-class classification and thus the accuracy of the classification is acquired. If the accuracy is acceptable, this diagnosis system can be used for future applications. Also, this study compared the accuracy of the proposed steel plate faults diagnosis system with that of other popular classification algorithms including Decision Tree, Multi Perception Neural Network (MLPNN), Logistic Regression (LR), Support Vector Machine (SVM), Tree Bagger Random Forest, Grid Search (GS), Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). The steel plates faults dataset used in the study is taken from the University of California at Irvine (UCI) machine learning repository. As a result, the proposed steel plate faults diagnosis system based on S-MTS shows 90.79% of classification accuracy. The accuracy of the proposed diagnosis system is 6-27% higher than MLPNN, LR, GS, GA and PSO. Based on the fact that the accuracy of commercial systems is only about 75-80%, it means that the proposed system has enough classification performance to be applied in the industry. In addition, the proposed system can reduce the number of measurement sensors that are installed in the fields because of variable optimization process. These results show that the proposed system not only can have a good ability on the steel plate faults diagnosis but also reduce operation and maintenance cost. For our future work, it will be applied in the fields to validate actual effectiveness of the proposed system and plan to improve the accuracy based on the results.