• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.48 no.4
• /
• pp.452-468
• /
• 2012

Marine organisms were collected by the stow nets and the stow net on boat fisheries from April 2010 to November 2011 in the Han River Estuary and categorized as 126 species, 61 families, and 5 taxa. The species were consisted with 34 in Crustacea, 5 in Cephalopoda, 79 in Pisces, unidentified jellyfishes in Cnidaria, and Finless porpoise in Mammals. The major species were composed of fish and crustaceans in the Han River Estuary. The dominant species in Crustacea were Chinese ditch prawn (Palaemon gravieri), blue crab (Portunus trituberculatus), Ridgetail prawn (Exopalaemon carinicauda), and mantis crab (Oratosquilla oratoria), and those in Pisces were Korean anchovy (Coilia nasus), and Japanese grenadier anchovy (Coilia mystus). The length structures of the six dominant species have more than one mode in the Han River Estuary. It reflects that the species inhibit during a part of and/or whole lifetime in the Han River Estuary where they utilize as spawning and/or nursery grounds. Freshwater fishes were collected from station D where is the closest location to the Han River stream, and their appearances were well matched with the large amount of freshwater discharge due to flood periods. Principal components analysis (PCA) was carried out with species compositions and showed temporal and spatial differences by the variations of species.

• Korean Journal of Food Science and Technology
• /
• v.26 no.5
• /
• pp.649-654
• /
• 1994

In order to provide a quality index of Korean folk sojues, physicochemical properties of Korean folk sojues (Andong soju, Moonbaesul, Leekangju, Jindo Hongju, Chebiwon soju, Yethyang (rice) and Yethyang (barley)), Paekrosul, Chinese kaoliangchiews (Moutaichiew, Ergoutoutiu, Chuyehchingchiew, Zhikukaoliangchiew and Paigal), Japanese Senbatanuki shochu and two whiskies were determined. The pH of sojues ($3.43{\sim}5.85$) were mainly influenced by total acidity which was described as acetic acid. The conductivities of Paekrosul and Leekangju showed relatively high value of $246\;and\;122.7{\mu}S/cm$, respectively. Korean folk sojues and Paekrosul showed maximum absorption at 274 or $278{\sim}280nm$ in the spectrometric study. We performed principal components analysis (PCA) of physicochemical properties and spectrometric data to extract representative characteristics and to compare the similarity or the dissimilarity. The PCA plot showed the distinguished cluster of Korean folk sojues comparing with Chinese kaoliangchiew or Paekrosul etc.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.4
• /
• pp.431-437
• /
• 2002

In order to understand the spatiotemporal variation of water quality, an investigation on variation characteristics of water quality was conducted at 13 stations in Yongil bay from 1990 to 1998. The salinity in summer was relatively lower than that in other seasons and it have increased from inner bay to outside of the bay gradually. However, nitrate concentration in summer was relatively higher than that in other seasons, and it was the highest, up to $65.40\%$, among dissolved inorganic nitrogens, Nitrate concentration indicates the possibility of affecting by freshwater discharges to Yongil bay. Correlation analysis showed that salinity had a significantly good correlation with nitrate. This result suggested that inflow of river had an influence on increase of nitrate. The result of Principal Component Analysis (PCA) indicated that nitrate was major factor to influence the water quality in Yongil Bay.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.46 no.6
• /
• pp.43-57
• /
• 2009

Integrating 3D data acquired in multiple views is one of the most important techniques in 3D modeling. However, the existing integration methods are sensitive to registration errors and surface scanning noise. In this paper, we propose a integration algorithm using the local surface topology. We first find all boundary vertex pairs satisfying a prescribed geometric condition in the areas between neighboring surfaces, and then separates areas to several regions by using boundary vertex pairs. We next compute best fitting planes suitable to each regions through PCA(Principal Component Analysis). They are used to produce triangles that be inserted into empty areas between neighboring surfaces. Since each regions between neighboring surfaces can be integrated by using local surface topology, a proposed method is robust to registration errors and surface scanning noise. We also propose a method integrating of textures by using parameterization technique. We first transforms integrated surface into initial viewpoints of each surfaces. We then project each textures to transformed integrated surface. They will be then assigned into parameter domain for integrated surface and be integrated according to the seaming lines for surfaces. Experimental results show that the proposed method is efficient to face modeling.

• KIPS Transactions on Software and Data Engineering
• /
• v.12 no.2
• /
• pp.59-76
• /
• 2023

Since the COVID-19 era, the rise in apartment prices has been unconventional. In this uncertain real estate market, price prediction research is very important. In this paper, a model is created to predict the actual transaction price of future apartments after building a vast data set of 870,000 from 2015 to 2020 through data collection and crawling on various real estate sites and collecting as many variables as possible. This study first solved the multicollinearity problem by removing and combining variables. After that, a total of five variable selection algorithms were used to extract meaningful independent variables, such as Forward Selection, Backward Elimination, Stepwise Selection, L1 Regulation, and Principal Component Analysis(PCA). In addition, a total of four machine learning and deep learning algorithms were used for deep neural network(DNN), XGBoost, CatBoost, and Linear Regression to learn the model after hyperparameter optimization and compare predictive power between models. In the additional experiment, the experiment was conducted while changing the number of nodes and layers of the DNN to find the most appropriate number of nodes and layers. In conclusion, as a model with the best performance, the actual transaction price of apartments in 2021 was predicted and compared with the actual data in 2021. Through this, I am confident that machine learning and deep learning will help investors make the right decisions when purchasing homes in various economic situations.

• Korean Journal of Environmental Biology
• /
• v.40 no.1
• /
• pp.70-86
• /
• 2022

A survey was conducted to analyze seasonal dynamics of the phytoplankton community at 22 stations on the surface and bottom layers in the Anma Islands of Yeonggwang(AIY) in the southern West Sea, Korea from the spring of 2020 to the winter of 2021, using a marine survey vessel Ed Ocean. Based on the survey results, there were 87 phytoplankton species in 52 genera, diatoms accounted for 67.8%, dinoflagellates 26.5%, silicoflagellates 3.5%, and cryptomonads and euglenoids accounted for 1.1% each. By season, it was simple in spring and relatively varied in winter. The phytoplankton standing crop on the surface was low (28.8±30.1 cells mL^-1) in summer and high (87.0±65.1 cells mL^-1) in spring. In the phytoplankton community, diatoms showed a high share (over 80%) throughout the year, and Skeletonema costatum-ls was the dominant species with a dominance of more than 60% in spring and winter, and 34.6% and 24.2% in summer and autumn, respectively. The diversity expressing the characteristics of the community structure was high (2.79±0.45) in autumn and low (1.82±0.18) in spring, unlike the phytoplankton standing crop. However, the dominance was high at (0.86±0.08) in spring and low (0.44j0.13) in autumn. Based on the results of principal component analysis (PCA) using environmental and phytoplankton-related factors, it was estimated that the biological oceanographic environmental characteristics seen through the phytoplankton community in the AIY were dominated by nutrients supplied from open seawater and surface sediments by seawater mixing, such as tidal mixing.

• Korean journal of food and cookery science
• /
• v.20 no.3
• /
• pp.279-286
• /
• 2004

The physicochemical and sensory qualities of pumpkin jams, in which sucrose was replaced with oligosaccharides, were investigated during storage at 20$^{\circ}C$. pumpkin jam was prepared with steamed grind pumpkin, mixed with either sucrose only(50％), corn syrup(COS, sucrose 30％＋COS 20％), fructooligosaccharide (FTO, sucrose 30％＋FTO 20％), isomaltooligo saccharide (IMO, sucrose 30％＋IMO 20％), or galactooligo-saccharide(GTO, sucrose 30％＋GTO 20％). The final sweetness of each pumpkin jam was 64$^{\circ}$ Brix. During 60days of storage there were no differences in acidity and pH among the treatments. Reducing sugar content was higher in the pumpkin jam containing COS compared to 次e others. During storage Lightness(Hunter L), redness(a value) and yellowness(b value) increased, of which L and b values were the highest in COS, and the a value were higher in sucrose compared to the other sugars. Adhesiveness and hardness of textural properties were the highest in sucrose. Sensory evaluation results showed that the mean scores of over-all acceptability during storage did not significantly decrease until the 30th day of storage, compared to the freshly made jams. Physicochemical and sensory characteristics of pumpkin jams during storage in a PCA plot were comprised of the first principal component (99.44％) and the second principal component (0.54％).

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.47 no.3
• /
• pp.61-69
• /
• 2010

This paper presents an efficient object selection algorithm by analyzing and detecting of human activity. Generally, when people point any something, they will put a face on the target direction. Therefore, the direction of the face and fingers and was ordered to be connected to a straight line. At first, in order to detect the moving objects from the input frames, we extract the interesting objects in real time using background subtraction. And the judgment of movement is determined by Principal Component Analysis and a designated time period. When user is motionless, we estimate the user's indication by estimation in relation to vector from the head to the hand. Through experiments using the multiple views, we confirm that the proposed algorithm can estimate the movement and indication of user more efficiently.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.41 no.6
• /
• pp.155-164
• /
• 2004

Recently, we have remarkable developments in intelligent robot systems. The remarkable features of intelligent robot are that it can track user and is able to doface recognition, which is vital for many surveillance-based systems. The advantage of face recognition compared with other biometrics recognition is that coerciveness and contact that usually exist when we acquire characteristics do not exist in face recognition. However, the accuracy of face recognition is lower than other biometric recognition due to the decreasing in dimension from image acquisition step and various changes associated with face pose and background. There are many factors that deteriorate performance of face recognition such as thedistance from camera to the face, changes in lighting, pose change, and change of facial expression. In this paper, we implement a new sliding active camera system to prevent various pose variation that influence face recognition performance andacquired frontal face images using PCA and HMM method to improve the face recognition. This proposed face recognition algorithm can be used for intelligent surveillance system and mobile robot system.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.6
• /
• pp.109-116
• /
• 2019

This study proposed a robust detection algorithm. It detects face more stably with respect to changes in light and rotation for the identification of a face shape. Also it satisfies both efficiency of calculation and the function of detection. The algorithm proposed segmented the face area through pre-processing using a face shape as input information in an environment with a single camera and then identified the shape using a Self Organized Feature Map(SOFM). However, as it is not easy to exactly recognize a face area which is sensitive to light, it has a large degree of freedom, and there is a large error bound, to enhance the identification rate, rotation information on the face shape was made into a database and then a principal component analysis was conducted. Also, as there were fewer calculations due to the fewer dimensions, the time for real-time identification could be decreased.