Adaptive Gaussian Low-pass Pre-filtering for Perceptual Video Coding

Wahyu Wiratama,Yong-Jo Ahn,Ismail Marzuki,Donggyu Sim 대한전자공학회 2018 IEIE Transactions on Smart Processing & Computing Vol.7 No.5

This paper proposes adaptive Gaussian low-pass pre-filtering for perceptually highquality video encoding, considering the characteristics of human visual perception. The proposed pre-filtering adaptively removes high-frequency components that are not visually perceptible. In the proposed algorithm, a pixel-wise adaptive Gaussian filter is generated based on a local contrast threshold for a block that is not highly textured. Each pixel for the block is adaptively filtered, and the original pixel is replaced by the filtered value or a weighted one that is a mixture of the filtered and original values for edge preservation. The proposed algorithm can remove visually imperceptible components, and leads to bit reduction without visual deterioration of the coded videos. Experimental results show that the proposed algorithm can reduce the bitrate by up to 30% with minimal computational complexity and minimal visual quality loss for several video sequences.

Evaluation of Thermal Hysteresis Activity of Ice-binding Proteins Using Ice-etching and Molecular Docking

Wahyu Sri Kunto Nugroho,우상욱,김학준 대한화학회 2018 대한화학회지 Vol.62 No.2

Ice-binding proteins have an affinity for ice. They create a gap between the melting and freezing points by inhibiting the growth of ice, known as thermal hysteresis (TH). Interestingly, moderately active LeIBP and hyperactive FfIBP are almost identical in primary and tertiary structures, but differ in TH activity. The TH of FfIBP is tenfold higher than that of LeIBP, due to a subtle difference in their ice-binding motifs. To further evaluate the difference in TH, the interactions were investigated by ice-etching and molecular docking. Ice-etching showed that FfIBP binds to the primary and secondary prism, pyramidal, and basal planes; previously, LeIBP was found to bind to the basal and primary prism planes. Docking analysis using shape complementarity (Sc) showed that the hyperactive FfIBP had higher Sc values for all four ice planes than LeIBP, which is comparable with TH. Docking can be used to describe the hyperactivity of IBPs.

Qualitative and Quantitative Anatomical Characteristics of Four Tropical Wood Species from Moluccas, Indonesia¹

Wahyu Hidayat,Yun Ki Kim,Woo Seok Jeon,Ju Ah Lee,Ah Ran Kim,Se Hwi Park,Rohny S Maail,Nam Hun Kim 한국목재공학회 2017 목재공학 Vol.45 No.4

The objective of this study was to compare the wood anatomical characteristics of local tree species in Moluccas, Indonesia i.e., Moluccan ironwood (Intsia bijuga), linggua (Pterocarpus indicus), red meranti (Shorea parvifolia), and gofasa (Vitex cofassus). Qualitative evaluation was conducted by observing the anatomical structure in cross, radial, and tangential sections of each sample. For the quantitative evaluation, the dimensions of vessels, rays, and fibers were measured. Qualitative evaluation showed that crystals were observed in Moluccan ironwood, linggua, and gofasa, while resin canals were only observed in red meranti. Tyloses were frequently observed in gofasa but infrequently observed in linggua and red meranti. Quantitative evaluation showed that Moluccan ironwood with the higher density had thicker fiber wall, higher quantity of ray number, and wider rays than the other species. Red meranti had higher values of ray height and fiber length than the other three species. The results also revealed that linggua showed the highest values of relative crystallinity and crystallite width. Red meranti and gofasa showed similar values of relative crystallinity and crystallite width, while Moluccan ironwood showed the lowest values. The basic qualitative and quantitative anatomical characteristics discussed could provide useful information for further utilizations of such wood species.

< 전시-P-18 > Viscoelastic properties of bamboo

( Wahyu Dwianto ),( Danang Sudarwoko Adi ),( Teguh Darmawan ),( Mohamad Gopar ),( Lisman Suryanegara ) 한국목재공학회 2018 한국목재공학회 학술발표논문집 Vol.2018 No.1

This study relates to measurement of the viscoelastic properties of bamboo to answer why bamboo is more easily bent than wood, whether this is related to its anatomical structure or its chemical components. To answer this question, static bending testing on the bamboo was done in dry, fresh, and after softening conditions. Andong (Gigantochloa pseudoarundinaceae (Steud.) Widjaja) bamboo which has potential as raw material of bamboo lamination was used in this experiments. For static bending tests, the bamboo internode was cut 30cm in length, 2cm in width and with varying thickness depending on the location of the internode on the stem (20 internodes/stem). Measurement results indicating that the diameter of the internode and its wall thickness decreases from the bottom to the top of internode. This causes moisture content of fresh bamboo decreases from the bottom to the top of internode. Modulus of rupture (MOR) increases, but its modulus of elasticity (MOE) decreases. This is due to the increased density towards the top of internode. Increased density is associated with anatomical structure, where in the top of internode, the portion of vascular bundles are greater than the parenchyma cells. Elastic limits, in-elastic limits, and maximum deflections before fracture is gradually decreases with different bamboo conditions from dry, fresh, and after softening. Anatomical structures will further observed from various curved radius after bent as well as the contents of chemical components analyzed to know the effect on softening condition of bamboo. Furthermore, the viscoelastic properties of bamboo will be compared with wood with the same density. However, it can be predicted that bamboo can be more easily bent because there are many parenchyma cells with thin-walled cells in the inner parts and more easily softened.

New Construction Detection with Remote Sensing Data

Wahyu Wiratama(위라타마 와유),Jongseok Lee(이종석),Kangseok Choi(최강석),Seung-Jun Oh(오승준),Donggyu Sim(심동규) 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.6

[< 전시-P-13 >] Consumer preference toward color of heat treated P inus koraienis and P aulownia tomentosa woods

( Wahyu Hidayat ),( Jae Hyuk Jang ),( Yun-ki Kim ),( Woo-seok Jeon ),( Ju-ah Lee ),( Nam Hun Kim ) 韓國木材工學會 2017 한국목재공학회 학술발표논문집 Vol.2017 No.1

The objective of this work was to investigate the effect of heat treatment on color changes and to determine determine the consumer preferences towards color of heat-treated woods. Korean white pine (Pinus koraiensis) and royal paulownia (Pauwlonia tomentosa) woods were treated at 160°C, 180°C, 200°C, and 220°C for 2 hours. The evaluation of color changes using the CIE-Lab color system showed that lightness (L^*) and red/green chromaticity (a^*) in both woods decreased with increasing temperature. Yellow/blue chromaticity (b^*) in Korean white pine tended to increase after heat treatment at 160°C, then decreased gradually afterwards. Overall color change (ΔE^*) increased with increasing temperature with higher degree obtained in royal paulownia. The results of the consumer preferences test showed that the darker colors of heat-treated woods were more preferred by consumers compared to the lighter colors of untreated woods.

Acceleration of Infrastructure Development in Indonesia through National Strategic Projects

Wahyu Utomo 한국지역개발학회 2020 한국지역개발학회 학술대회 Vol.2020 No.10

Cloning, Expression, and Characterization of a Cold-Adapted Shikimate Kinase from the Psychrophilic Bacterium Colwellia psychrerythraea 34H

( Wahyu Sri Kunto Nugroho ),( Dong-woo Kim ),( Jong-cheol Han ),( Young Baek Hur ),( Soo-wan Nam ),( Hak Jun Kim ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.12

Most cold-adapted enzymes possess higher K_m and k_cat values than those of their mesophilic counterparts to maximize the reaction rate. This characteristic is often ascribed to a high structural flexibility and improved dynamics in the active site. However, this may be less convincing to cold-adapted metabolic enzymes, which work at substrate concentrations near K_m. In this respect, cold adaptation of a shikimate kinase (SK) in the shikimate pathway from psychrophilic Colwellia psychrerythraea (CpSK) was characterized by comparing it with a mesophilic Escherichia coli homolog (EcSK). The optimum temperatures for CpSK and EcSK activity were approximately 30°C and 40°C, respectively. The melting points were 33°C and 45°C for CpSK and EcSK, respectively. The ΔG_H2O (denaturation in the absence of denaturing agent) values were 3.94 and 5.74 kcal/mol for CpSK and EcSK, respectively. These results indicated that CpSK was a cold-adapted enzyme. However, contrary to typical kinetic data, CpSK had a lower K_m for its substrate shikimate than most mesophilic SKs, and the k_cat was not increased. This observation suggested that CpSK may have evolved to exhibit increased substrate affinity at low intracellular concentrations of shikimate in the cold environment. Sequence analysis and homology modeling also showed that some important salt bridges were lost in CpSK, and higher Arg residues around critical Arg 140 seemed to increase flexibility for catalysis. Taken together, these data demonstrate that CpSK exhibits characteristics of cold adaptation with unusual kinetic parameters, which may provide important insights into the cold adaptation of metabolic enzymes.

A Review on Remote Sensing and GIS Applications to Monitor Natural Disasters in Indonesia

( Wahyu Luqmanul Hakim ),( Chang-wook Lee ) 대한원격탐사학회 2020 大韓遠隔探査學會誌 Vol.36 No.6

Indonesia is more prone to natural disasters due to its geological condition under the three main plates, making Indonesia experience frequent seismic activity, causing earthquakes, volcanic eruption, and tsunami. Those disasters could lead to other disasters such as landslides, floods, land subsidence, and coastal inundation. Monitoring those disasters could be essential to predict and prevent damage to the environment. We reviewed the application of remote sensing and Geographic Information System (GIS) for detecting natural disasters in the case of Indonesia, based on 43 articles. The remote sensing and GIS method will be focused on InSAR techniques, image classification, and susceptibility mapping. InSAR method has been used to monitor natural disasters affecting the deformation of the earth’s surface in Indonesia, such as earthquakes, volcanic activity, and land subsidence. Monitoring landslides in Indonesia using InSAR techniques has not been found in many studies; hence it is crucial to monitor the unstable slope that leads to a landslide. Image classification techniques have been used to monitor pre-and post-natural disasters in Indonesia, such as earthquakes, tsunami, forest fires, and volcano eruptions. It has a lack of studies about the classification of flood damage in Indonesia. However, flood mapping was found in susceptibility maps, as many studies about the landslide susceptibility map in Indonesia have been conducted. However, a land subsidence susceptibility map was the one subject to be studied more to decrease land subsidence damage, considering many reported cases found about land subsidence frequently occur in several cities in Indonesia.

Characterization of heat treated wood from Korean white pine (Pinus Koraiensis) and Royal Paulownia (Paulownia tomentosa)

( Wahyu Hidayat ),( Jaehyuk Jang ),( Yunki Kim ),( Wooseok Jeon ),( Juah Lee ),( Namhun Kim ) 韓國木材工學會 2016 한국목재공학회 학술발표논문집 Vol.2016 No.2

The objective of this work is to investigate the effect of heat treatment on color changes, wettability, physical and mechanical properties of Korean white pine (Pinus koraiensis) and Royal paulownia (Paulownia tomentosa). Samples were heat treated using an electric oven with a programmable controller at 160°C, 180°C, 200°C, and 220°C for 2 h. The results showed that the color of heat treated wood became darker with the increase of temperature. The weight loss and volume shrinkage increased with the increase of temperature. Heat treated wood evidently absorbed less water than control, showing lower equilibrium moisture content and water absorption. The wettability of wood decreased with heat treatment. In addition, Royal paulownia showed higher degree of change in contact angles than Korean white pine. Evaluation of mechanical properties showed that modulus of rupture (MOR) and modulus of elasticity (MOE) in both woods decreased with the increase of temperature. However heat treatment at 160°C tended to increase the MOE of wood.