• Journal of Korea Multimedia Society
• /
• v.22 no.4
• /
• pp.443-454
• /
• 2019

In recent years, there has been active research on a recommender system that considers three or more inputs in addition to users and goods, making it a multi-dimensional array, also known as a tensor. The main issue with using tensor is that there are a lot of missing values, making it sparse. In order to solve this, the tensor can be shrunk using the tensor decomposition algorithm into a lower dimensional array called a factor matrix. Then, the tensor is reconstructed by calculating factor matrices to fill original empty cells with predicted values. This is called tensor reconstruction. In this paper, we propose a user-based Top-K recommender system by normalized PARAFAC tensor reconstruction. This method involves factorization of a tensor into factor matrices and reconstructs the tensor again. Before decomposition, the original tensor is normalized based on each dimension to reduce overfitting. Using the real world dataset, this paper shows the processing of a large amount of data and implements a recommender system based on Apache Spark. In addition, this study has confirmed that the recommender performance is improved through normalization of the tensor.

• Convergence Security Journal
• /
• v.18 no.5_1
• /
• pp.93-98
• /
• 2018

Korea Hydro & Nuclear Power Co., Ltd., Korea Electric Power Corporation, and Korea South-East Power Corporation are major infrastructure facilities of power supplying countries. If a malicious hacking attack occurs, the damage is beyond the imagination. In fact, Korea Hydro & Nuclear Power has been subjected to a hacking attack, causing internal information to leak and causing social big problems. In this paper, we propose a strategy and countermeasures for stabilization of various power generation control systems by analyzing the environment and the current status of power generation control system for convergence security research, which is becoming a hot issue. We propose a method to normalize and integrate data types from various physical security systems (facilities), IT security systems, access control systems, to control the whole system through convergence authentication, and to detect risks through fusion control.

• Advances in concrete construction
• /
• v.10 no.6
• /
• pp.527-536
• /
• 2020

In this study, a process is proposed to calculate analytical correction values for the vertical shortening of all columns on all floors in a high-rise building that minimizes the error between the structural analysis predictions and values measured during construction. The weight ratio and the most probable value were accordingly considered based on the properties of the shortening value analyzed at several points in each construction stage and the distance between these measured points and unmeasured points at which the shortening was predicted. The effective range and shortening value normalization were considered using the column grouping concept. These tools were applied to calculate the error ratio between the predicted and measured values on a floor where a measured point exists, and then determine the estimated error ratio and estimated error value for the unmeasured point using this error ratio. At points on a floor where no measured point exists, the estimated error ratio and the estimated error value were calculated by applying the most probable value considering the weight ratio for the nearest floor where measured points exist. In this manner, the error values and estimated error values can be determined at all points in a structure. Then, the analytical correction value, defined as this error or estimated error value, was applied by adding it to the predicted value. Finally, the adequacy of the proposed correction method was verified against measurements by applying the analytical corrections to all unmeasured points based on the points where the measurement exists.

• Journal of the Korean Society of Food Culture
• /
• v.36 no.1
• /
• pp.28-39
• /
• 2021

This study considered the rite of passage ceremonial food in the Mid-Choseon Period through the rite of passage ceremonies, food, and ingredients recorded in the Seoul Noble Ohhweemun Family Diary Shaemirok. The research used a contents analysis method through case studies. The noble families in the Mid-Choseon Period deemed the Jerye to be the most significant out of the traditional ceremonies. The nobles practiced the Sadehbongsah and the Yoonhweebongsah ceremonies for their ancestors. The Rite of passage ceremony required fruit. Of fish and birds, pheasants were used frequently during the ceremonies. Noble families, specifically the richer families, could sustainably normalize the rite of passage ceremonies against the elements. Seasonal ingredients were generally harvested even during spring and winter in large amounts. One of the last rites of passage food by Garye displayed diverse ingredients, such as Bangaeng, Myun, Tang, Uhyookjuk, Poe, Chae, Hae, and Silgwa. Such ingredients prove that the normalization of rite of passage ceremony food was well established and practiced. On the other hand, the birthday rite of passage food did not conform to a specific rite of passage normalcy or preparation. Instead, the birthday food showed a flexible menu of seasonal delicacies that were not confined to a particular traditional formula.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.16 no.11
• /
• pp.3761-3779
• /
• 2022

The performance of existing recognition algorithms for binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) signals degrade under conditions of low signal-to-noise ratios (SNR). Hence, a novel recognition algorithm based on features in the graph domain is proposed in this study. First, the power spectrum of the squared candidate signal is truncated by a rectangular window. Thereafter, the graph representation of the truncated spectrum is obtained via normalization, quantization, and edge construction. Based on the analysis of the connectivity difference of the graphs under different hypotheses, the sum of degree (SD) of the graphs is utilized as a discriminate feature to classify BPSK and QPSK signals. Moreover, we prove that the SD is a Schur-concave function with respect to the probability vector of the vertices (PVV). Extensive simulations confirm the effectiveness of the proposed algorithm, and its superiority to the listed model-driven-based (MDB) algorithms in terms of recognition performance under low SNRs and computational complexity. As it is confirmed that the proposed method reduces the computational complexity of existing graph-based algorithms, it can be applied in modulation recognition of radar or communication signals in real-time processing, and does not require any prior knowledge about the training sets, channel coefficients, or noise power.

• Nuclear Engineering and Technology
• /
• v.55 no.8
• /
• pp.2854-2863
• /
• 2023

Objective: To present a hybrid approach that incorporates a constrained beam-hardening estimator (CBHE) and deep learning (DL)-based post-refinement for metal artifact reduction in dental cone-beam computed tomography (CBCT). Methods: Constrained beam-hardening estimator (CBHE) is derived from a polychromatic X-ray attenuation model with respect to X-ray transmission length, which calculates associated parameters numerically. Deep-learning-based post-refinement with an artifact disentanglement network (ADN) is performed to mitigate the remaining dark shading regions around a metal. Artifact disentanglement network (ADN) supports an unsupervised learning approach, in which no paired CBCT images are required. The network consists of an encoder that separates artifacts and content and a decoder for the content. Additionally, ADN with data normalization replaces metal regions with values from bone or soft tissue regions. Finally, the metal regions obtained from the CBHE are blended into reconstructed images. The proposed approach is systematically assessed using a dental phantom with two types of metal objects for qualitative and quantitative comparisons. Results: The proposed hybrid scheme provides improved image quality in areas surrounding the metal while preserving native structures. Conclusion: This study may significantly improve the detection of areas of interest in many dentomaxillofacial applications.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.65 no.2
• /
• pp.47-57
• /
• 2023

The increase of impermeable area ratio is causing hydrologic cycle problems in urban areas and groundwater depletion in rural areas, permeable pavements are getting attention to expand permeable areas. The performance of the permeable concrete block pavement, which is part of the permeable pavement, is greatly affected by the porosity. In addition, the permeability coefficient is a major factor when designing permeable concrete block pavement. Existing porosity and permeability test methods have problems such as uneconomical or poor field applicability. The object of this study was to develop a methodology for evaluating porosity and permeability coefficient using a surface image of a permeable concrete block. Specimens are manufactured with various porosity ranges and porosity and permeability tests are performed. After surface image preprocessing, normalization and binarization methods were compared. Through this, the method with the highest correlation with the lab test result was determined. From the results, the PDR (pore determined ratio) was obtained. Simple linear regression analysis is performed with PDR and lab test results. The results showed a high correlation of R² more than 0.8, and the errors were also low.

• Genomics & Informatics
• /
• v.21 no.2
• /
• pp.24.1-24.7
• /
• 2023

Assays of clinical diagnosis and species identification using molecular markers are performed according to a quantitative method in consideration of sensitivity, cost, speed, convenience, and specificity. However, typical polymerase chain reaction (PCR) assay is difficult to quantify and have various limitations. In addition, to perform quantitative analysis with the quantitative real-time PCR (qRT-PCR) equipment, a standard curve or normalization using reference genes is essential. Within the last a decade, previous studies have reported that the digital PCR (dPCR) assay, a third-generation PCR, can be applied in various fields by overcoming the shortcomings of typical PCR and qRT-PCR assays. We selected Stilla Naica System (Stilla Technologies), Droplet Digital PCR Technology (Bio-Rad), and Lab on an Array Digital Real-Time PCR analyzer system (OPTOLANE) for comparative analysis among the various droplet digital PCR platforms currently in use commercially. Our previous study discovered a molecular marker that can distinguish Hanwoo species (Korean native cattle) using Hanwoo-specific genomic structural variation. Here, we report the pros and cons of the operation of each dPCR platform from various perspectives using this species identification marker. In conclusion, we hope that this study will help researchers to select suitable dPCR platforms according to their purpose and resources.

• Biomedical Science Letters
• /
• v.29 no.4
• /
• pp.220-230
• /
• 2023

Identification of the pathogens causing infection is important in terms of patient's health management and infection control. Synovial fluids could be used as clinical samples to detect causative pathogens of prosthetic joint infections (PJIs) using molecular diagnostic assays, therefore, normalization and validation of clinical samples are necessary. Microbial culture is considered the gold standard for all infections, including PJIs. Recently, molecular diagnostic methods have been developed to overcome the limitation of microbial culture. Therefore, guideline for validating clinical samples to provide reliable results of molecular diagnostic assays for infectious diseases is required in clinical field. The present study aimed to develop an accurate validating method of synovial fluid clinical samples using GAPDH gene as an internal control to perform the quantitative PCR TaqMan probe assay to detect pathogens causing PJIs.

• Journal of the Korea Society of Computer and Information
• /
• v.29 no.5
• /
• pp.47-53
• /
• 2024

In this paper, we propose applying interactive technology in virtual environments to enhance interaction and immersion by inducing more natural movements in the gesture recognition process through the concept of affordance. A technique is proposed to recognize gestures most similar to actual hand movements by applying a line segment recognition algorithm, incorporating sampling and normalization processes in the gesture recognition process. This line segment recognition was applied to the drawing of magic circles in the <VR Spell> game implemented in this paper. The experimental method verified the recognition rates for four line segment recognition actions. This paper aims to propose a VR game that pursues greater immersion and fun for the user through real-time hand tracking technology using affordance Elements, applied to immersive content in virtual environments such as VR games.