• Resources Recycling
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• v.31 no.6
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• pp.81-91
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• 2022

The use of lithium-ion batteries increases significantly with the rapid spread of electronic devices and electric vehicle and thereby an increase in the amount of waste batteries is expected in the near future. Therefore, studies are continuously being conducted to recover various resources of cathode active material (Ni, Co, Mn, Li) from waste battery. In order to recover the cathode active material, black mass is generally recovered from waste battery. The general process of recovering black mass is a waste battery collection - discharge - dismantling - crushing - classification process. This study focus on the crushing/classification process among the processes. Specifically, the particle size distribution of various samples at each crushing/classification step were evaluated, and the particle shape of each particle fraction was analyzed with a microscope and SEM (Scanning Electron Microscopy)-EDS(Energy Dispersive Spectrometer). As a result, among the black mass particle, fine particle less than 74 ㎛ was the mixture of cathode and anode active material which are properly liberated from the current metals. However, coarse particle larger than 100 ㎛ was present in a form in which the current metal and active material were combined. In addition, this study developed a PBM(Population Balance Model) system that can simulate two-species mixture sample with two different crushing properties. Using developed model, the breakage parameters of two species was derived and predictive performance of breakage distribution was verified.

• Asia Marketing Journal
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• v.15 no.2
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• pp.75-97
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• 2013

While good return policies are suggested as one of the critical services for e-commerce, ambivalence between the burden of the cost and shoppers' satisfaction may prevent e-tailers from increasing their level of leniency. Based on the S-O-R model, this study has attempted to develop a grounded theory to explain how lenient return policies shape online shoppers' perceptions and responses, with a focus on cultural influences in the relationship. In order to check the cultural effects of the lenient return policy, thirty two female and eleven male undergraduate students in South Korean shoppers, who are accustomed to strict return policies, participated in the semi-structured interview. A series of open-ended questions were designed to explore consumers' reactions toward four different levels of the lenient return policy: from the strict type in South Korea to the lenient type in the U.S. Using qualitative research methods, this research has defined three types of dimensions of lenient return policy: return possible period, complexity of progress, and other restrictions. While previous researchers did not pay much attention, the last dimension, other restrictions, is shown to be the most significant in influencing online shoppers' perceptions, especially in South Korea. Also, the impacts on online shoppers' perceptions from the three types of sub-dimensions of return policy were somewhat different. Whereas a longer return possible period was considered more favorable, a medium level of complexity and restrictions were considered more desirable. In summary, this result showed that shoppers in Eastern cultures, i.e. South Korean online shoppers, seem favorable to a medium level of lenient return policies, while allowing for taking precautions against possible fraudulent behaviors and setting other restrictions. Therefore, most of retailers in South Korea recommended that e-tailers who adopt the most lenient return policies raise the bar to guard ethical shoppers from fraudulent users. Next, lenient return policies can enhance ease of use, usefulness, affect, and trust while relieving perceived risk, which is connected to intention to purchase, satisfaction, and loyalty. Interestingly, lenient return policies are more likely to change the behavioral responses of online shoppers, such as return and purchase, rather than change their attitudes or beliefs such as image, satisfaction, and loyalty. This tendency can be seen more clearly in the direct influences of return policy on responses. The reaction to lenient return policy is mostly the intention to return or to purchase. This suggests that return policy serves the e-tailers as a powerful tool in increasing online shoppers' purchase intention at the moment of purchase. Therefore, e-tailers who plan to expand their market to eastern countries, including South Korea, have to build a shield of restrictions around their lenient return policy, rather than immediately applying their original liberalized return policy. Also, e-tailers in South Korea need to review their strict and undifferentiated return policies to deal with the unsatisfied reactions of online shoppers toward their normal return policies. Although the present study was confined to the return policies currently being practiced by popular e-tailers, it would be worthwhile to develop effective return policies separately for each country, especially South Korea, keeping the culture of the relevant country in mind.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.3
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• pp.179-188
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• 1981

The authors made an investigation concerning the geographical distribution and some major differentiations in morphological characteristics associated with the each habitat, of the pond smelt, Hypomesus olidus, which was introduced into Korea more than 50 years ago. Major characteristics utilized for the comparison study were upper jaw (maxillary), number of fin rays, scale structure, vertebral count, number of pyloric caeca, number of gill rakers, and the relative measurements of these and other internal characters. 1. The main areas of natural distribution are Paro Lake, Soyang Lake, Han River, Euirim Lake, and Ogjeong Lake (or Unam Lake) and the tributaries of these waters. 2. Morphological variations varied when the mean values of measurements from each area were compared with the standard measurement value by mosaic comparison, and in some instances a significant variation was found. 3. The most significant variations were found in the number of fin rays of pectoral and anal fins; the lengths from the tip of snout to the origin of pectoral fin, from snout to ventral fin, and from snout to anal fin, relative to standard body length; eye depth relative to head length; upper jaw: the number of pyloric caeca and the scale structure. Variations, on the other hand, by each habitat were not clear in the numbers of ventral and dorsal fin rays, gill rakers, vertebrae and lateral line scale : and the depth of caudal peduncle and distance from the tip of snout to the origin of dorsal fin relative to standard body length. 4. The scales of pond smelt showed some differences in the shape of scales, the shape and position of the focus and the number of ridges according to the scale positions on the body. No radii were present. The relations between longitudinal and transverse diameters of the scale suggest that the pond smelts of Soyang Lake and Un-am Lake are closely related, and those of Han River and Euirim Lake are also closely related. 5. The geographical variations in morphology of the pond smelt seem to have resulted from the variations in turbidity, water temperature, salinity (rather conductivity) and currents. 6. From the results obtained, it may be concluded that such factors as supramaxillary, relation between scale length and its breadth, number of caudal vertebrae and eye depth relative to head length may be used as the key characters for the classification of geographical varieties of Pond smelt.

• Korean Journal of Heritage: History & Science
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• v.54 no.1
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• pp.280-301
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• 2021

Chogak has been regarded as originating from the paintings decorating building elements. Various curved shape drawings that were first seen in the paintings of Goguryeo tomb murals evolved into the vine patterned Dancheong of Geuklakjeon in Bongjeongsa. Cheomcha of Geuklakjeon was chiseled with Yeonhwadusik relievo at the bottom on top of Dancheong, and this was the beginning of Cheomcha-Chogak. Also, Cheomcha, which was carved with a preliminary vine patterned Chogak in Daeungjeon in Bongjeongsa, opened the era of engraving Chogak directly on the surface of structural elements. Since then, vine patterned Chogak was a significant decoration technique for the Cheomcha of traditional wooden construction for a long time. Because Jeongjagak is a structure that was continuously built between the end of the Japanese invasion of Korea in 1592 and the late Joseon Dynasty, the transition of Cheomcha-Chogak over time can be seen through Jeongjagak architecture. The early Cheomcha-Chogak presents stems that climb up (Upbound-type) towards the headpiece on a column, while stems of Chogak later reversed direction to descend (Downbound-type) from the headpiece. This study examined the transition process and reasons for the change, with a focus on the findings above, and identified a new type of Chogak that is unrelated to the direction type and was adopted during the transition from Upbound-type to Downbound-type. The new type appeared when the Jeongjagaks for the Royal Tomb of Kyeongjo and those of the Injo were built, and it matches with the transitional period wherein lotus vanishes from Hwaban-Chogak. The study also inferred that the direction change of Cheomcha-Chogak stems was caused by the separation of vine patterned Chogak, carved with a two-stepped inner Ikgon, into both upward and downward from the headpiece, and this led to the changes that manifested as the inside of Choikgong being the Downbound-type Chogak and the variegated vine patterned Chogak of Choikgong affecting the direction of Cheomcha-Chogak. This is the follow-up study of "A Study on the Hwaban-Chogak of the Neungwon-Jeongjagak," a paper published in 2018, and is limited in n that Cheomcha, the focus of the research, is just one of the construction elements of Jeongjagak. The entirety ofChogak cannot be understood only by observing Cheomcha.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.2
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• pp.91-108
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• 2022

In most cases, optical images have been used as training data of DL (Deep Learning) models for object detection, recognition, identification, classification, semantic segmentation, and instance segmentation. However, properties of 3D objects in the real-world could not be fully explored with 2D images. One of the major sources of the 3D geospatial information is DSM (Digital Surface Model). In this matter, characteristic information derived from DSM would be effective to analyze 3D terrain features. Especially, man-made objects such as buildings having geometrically unique shape could be described by geometric elements that are obtained from 3D geospatial data. The background and motivation of this paper were drawn from concept of the intrinsic image that is involved in high-level visual information processing. This paper aims to extract buildings after classifying terrain features by training DL model with DSM-derived information including slope, aspect, and SRI (Shaded Relief Image). The experiments were carried out using DSM and label dataset provided by ISPRS (International Society for Photogrammetry and Remote Sensing) for CNN-based SegNet model. In particular, experiments focus on combining multi-source information to improve training performance and synergistic effect of the DL model. The results demonstrate that buildings were effectively classified and extracted by the proposed approach.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.4
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• pp.94-104
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• 2018

This study examined photogrammetric reconstruction techniques that can measure the original form of a cultural property utilizing photographs taken in the past. During the research process, photographs taken in the past as well as photograph on the internet of Soswaewon Garden in Damyang(scenic site 40) were collected and utilized. The landscaping structures of Maedae, Aiyangdan, Ogokmun Wall, and Yakjak and natural scenery Gwangseok, of which photographs can be taken from any 360 degree direction from a close distance or a far distance without any barriers in the way, were selected and tested for the possibility of reproducing three-dimensional shapes. The photography method of 151 landscape photographs (58.6%) from internet portal sites for the aforementioned five landscape subjects containing information on the date the photograph was taken, focal length, and exposure were analyzed. As a result of the analysis, it was revealed that the majority of the photographs tend to focus on important parts of each subject. In addition, we discovered that there are two or three photography methods that internet users preferred in regards to each landscape subject. For the purposes of the experiment, photographs in which a single scene consistently appears for each landscape subject and it was determined that there was a high level of preference related to the photography method were analyzed, and three-dimensional mesh shape model was produced with a photoscan program to analyze the reproducibility of three-dimensional shapes. Based on the results of the reproduction, it was relatively possible to reproduce three-dimensional shapes for artifacts such as Ogukmun wall, Maedae, and Aeyangdan, but it was impossible to reproduce three-dimensional images for natural scenery or an object that has similar texture such as Yakjak and Gwangseok. As a result of experimentation related to the reconstruction of three-dimensional shapes with the photographs taken on site using a photography method similar to that of the photographs selected as previously mentioned, there was success related to reproducing the three-dimensional shapes of Yakjak and Gwangseok, of which it was not possible to do so through the photographs that had been collected previously. In addition, through comparison of past and present images, it was possible to measure the exact sizes as well as discover any changes that have taken place. If past photographs taken by tourists or landscape architects of cultural properties can be obtained, the three-dimensional shapes from a particular period of time can be reproduced. If this technology becomes widespread, it will increase the level of accuracy and reliability in regards to measuring the past shapes of cultural landscape properties and examining any changes to the properties.

• Journal of Periodontal and Implant Science
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• v.40 no.1
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• pp.3-10
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• 2010

Purpose: Periodontal regenerative therapies for defects created by severe periodontitis are mainly focused on bone regeneration. Although cementum regeneration needs to be better understood, it is believed to play an important role in periodontal regeneration. The first step toward a full understanding of cementum regeneration is to compare repaired cementum to pristine cementum. This study, which used histological techniques, was designed to focus on cementum regeneration and to compare pristine cementum to repaired cementum after surgical procedures with 8 and 24 week healing periods in a canine model. Methods: Buccal and lingual mucoperiosteal flaps of 10 beagle dogs were surgically reflected to create critical-sized defects. Intrabony one-wall defects, of which dimension is 4 mm width and 5 mm depth, were made at the distal aspect of mandibular second premolars and the mesial aspect of mandibular fourth premolars in the right and left jaw quadrants. Animals were sacrificed after 8 and 24 weeks post-surgery for histological specimen preparation and histometric analysis. Results: The repaired cementum was composed mostly of acellular cementum and cellular mixed fiber cementum and was thicker in the apical area than in the coronal area. The acellular cementum of the supracrestal area appeared to be amorphous. The newly formed cellular cementum was partially detached from the underlying circumpulpal dentin, which implied a weak attachment between new cementum and dentin, and this split was observed to a lesser extent in the 24 week group than in the 8 week group. The vertical height of the repaired cementum was greater in the 24 week group than in the 8 week group. Conclusions: Within the limitations of this study, we can conclude that repaired cementum after root planing was mainly acellular cementum and cementum tissue that matured to a shape similar to pristine cementum as the healing progressed from 8 to 24 weeks.

• Journal of Forest and Environmental Science
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• v.30 no.4
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• pp.383-392
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• 2014

In this study, we investigated the Fukiage sand dunes of southern Kyushu, Japan. We surveyed the status of recovery of coastal Japanese black pine forests damaged by pine wilt disease and their disaster prevention capability. We placed two transects: Transect 1, in an area that was severely damaged (80-90% damage rate) by pine wilt disease, and Transect 2, in an area that was mostly undamaged (<10% damage rate). Then, we installed survey lines, carried out vegetation surveys, and measured the depth and pH of humus soil. The survey lines were placed perpendicular to the coastline from the top of the fore-dune to the inland area, and divided into five 50 m sections. Before the point 100 m inland from the top of the fore-dune, the number of invasive hardwoods and of Japanese black pines were small because of the poor growth environment in both transects. Past the 100 m point, the species and number of Japanese black pines and broad-leaved trees increased further inland because the growth environment improved. In addition, the recovery metrics of tree height, diameter at breast height, age, and number in Transect 1 were much lower than those in Transect 2, and the basal area of broad-leaved trees and the depth of humus soil in Transect 1 were lower than in Transect 2, and the soil pH of humus soil in Transect 1 was higher than that of Transect 2. The shape ratio of the Japanese black pine forests indicated that they were insufficient for disaster prevention. Therefore, in order to fully promote the disaster prevention capability of coastal Japanese black pine forests, we should not only focus on prevention of pine wilt disease but also undertake continuous control efforts taking into consideration the sound growth environment such as appropriate density and soil management and removal of invasive broad-leaved trees.

• Korean Journal of Heritage: History & Science
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• v.51 no.4
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• pp.24-43
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• 2018

Thirty-five of Hwaban of Jeongjagak had been built in the last three hundred years, which means a Hwaban was made in almost every ten years. Jeongjagak is a building that requires a certain ornamentation having the identical Gongpo type, called E-ikgong, and maintains the same shape for a long time. While Hwaban is an element that faithfully serves the ornamental role, the field study found that Hwaban-chogak went through various changes over the years unlikely to Jeongjagak. This study enumerates and classifies the various types of Hwaban-chgak by outlining the similarities/differences of the various types of Hwavanchogak, and by discovering what the craftsmen aimed to express through the Hwaban-chogaks. As a result, Hwaban-chogak can be generally divided into two categories depending on the starting point of Chogak: 'Downward-Type' and 'Upward-type' and the study tried to find the origin of that. The first represents the stems of Hwaban crafts flowing from top to bottom, and the latter showing the opposite direction. Around 1740s Upward-type can be chronologically caragorised as; 'original- type' which contains lotus and 'modified- type' which eliminates lotus. It is inferred that the modified-type was caused by the employment system of the craftsmen. It is also recognized that the main frame of Hwaban-chogak had been maintained despite the fact that Chogak became increasingly ornamental for the next a hundred years from the Hwaban-chogak drawings in Whaseong-seongyeog-uigwe, which was completed in 1796. The study has a limitation that the focus of the research is only on the Hwaban of Jeongjagak and expected to look into Hwaban in the context of other construction elements such as Ikgong, Daegong and Anchogong for further studies.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.58.1-59
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• 2021

Exploration of asteroids' internal structure is essential for understanding their evolutional history. It also provides a fundamental information about the history of coalescence and collision of the solar system. Among several models of the internal structures, the rubble-pile model, confirmed by the near-Earth asteroid (25143) Itokawa by Hayabusa mission [1], is now widely regarded as the most common to asteroids with size ranging from 200 m to 10 km [2]. On the contrary, monolithic and core-mantle structures are also possible for small asteroids [3]. It is, however, still challenging to look through the interior of a target object using remote-sensing devices. In this presentation, we introduce our ongoing research conducted at Seoul National and propose an idea to infer the internal structure of Apophis using available instruments. Itokawa's research provides an important benchmark for Apophis exploration because both asteroids have similar size and composition [4][5]. We have conducted research on Itokawa's evolution in terms of collision and space weathering. Space weathering is the surface alteration process caused by solar wind implantation and micrometeorite bombardment [6]. Meanwhile, resurfacing via a collision acts as a counter-process of space weathering by exposing fresh materials under the matured layer and lower the overall degree of space weathering. Therefore, the balance of these two processes determine the space weathering degrees of the asteroid. We focus on the impact evidence on the boulder surface and found that space weathering progresses in only 100-10,000 years and modifies the surface optical properties (Jin & Ishiguro, KAS 2020 Fall Meeting). It is important to note that the timescale is significantly shorter than the Itokawa's age, suggesting that the asteroid can be totally processed by space weathering. Accordingly, our result triggers a further discussion about why Itokawa indicates a moderately fresh spectrum (Sq-type denotes less matured than S-type). For example, Itokawa's smooth terrains show a weaker degree of space weathering than other S-type asteroids [7]. We conjecture that the global seismic shaking caused by collisions with >1 mm-sized interplanetary dust particles induces granular convection, which hinders the progression of space weathering [8]. Note that the efficiency of seismic wave propagation is strongly dependent on the internal structure of the asteroid. Finally, we consider possible approaches to investigate Apophis's internal structure. The first idea is studying the space weathering age, as conducted for Itokawa. If Apophis indicates a younger age, the internal structure would have more voids [9]. In addition, the 2029 close encounter with Earth provides a rare natural opportunity to witness the contrast between before and after the event. If the asteroid exhibits a slight change in shape and space weathering degree, one can determine the physical structure of the internal materials (e.g., rubble-pile monolithic, thick or thin regolith layer, the cohesion of the materials). We will also consider a possible science using a seismometer.