• Journal of the Korea Society of Computer and Information
• /
• v.28 no.10
• /
• pp.133-153
• /
• 2023

In this paper, we propose a novel approach to investigating brain-signal measurement technology using Electroencephalography (EEG). Traditionally, researchers have combined EEG signals with bio-signals (BSs) to enhance the classification performance of emotional states. Our objective was to explore the synergistic effects of coupling EEG and BSs, and determine whether the combination of EEG+BS improves the classification accuracy of emotional states compared to using EEG alone or combining EEG with pseudo-random signals (PS) generated arbitrarily by random generators. Employing four feature extraction methods, we examined four combinations: EEG alone, EG+BS, EEG+BS+PS, and EEG+PS, utilizing data from two widely-used open datasets. Emotional states (task versus rest states) were classified using Support Vector Machine (SVM) and Long Short-Term Memory (LSTM) classifiers. Our results revealed that when using the highest accuracy SVM-FFT, the average error rates of EEG+BS were 4.7% and 6.5% higher than those of EEG+PS and EEG alone, respectively. We also conducted a thorough analysis of EEG+BS by combining numerous PSs. The error rate of EEG+BS+PS displayed a V-shaped curve, initially decreasing due to the deep double descent phenomenon, followed by an increase attributed to the curse of dimensionality. Consequently, our findings suggest that the combination of EEG+BS may not always yield promising classification performance.

• Korean Journal of Materials Research
• /
• v.34 no.4
• /
• pp.185-193
• /
• 2024

In this study, NASICON-type Li_1+XGa_XTi_2-X(PO₄)₃ (x = 0.1, 0.3 and 0.4) solid-state electrolytes for all-solid-state batteries were synthesized through the sol-gel method. In addition, the influence on the ion conductivity of solid-state electrolytes when partially substituted for Ti⁴⁺ (0.61Å) site to Ga³⁺ (0.62Å) of trivalent cations was investigated. The obtained precursor was heat treated at 450 ℃, and a single crystalline phase of Li_1+XGa_XTi_2-X(PO₄)₃ systems was obtained at a calcination temperature above 650 ℃. Additionally, the calcinated powders were pelletized and sintered at temperatures from 800 ℃ to 1,000 ℃ at 100 ℃ intervals. The synthesized powder and sintered bodies of Li_1+XGa_XTi_2-X(PO₄)₃ were characterized using TG-DTA, XRD, XPS and FE-SEM. The ionic conduction properties as solid-state electrolytes were investigated by AC impedance. As a result, Li_1+XGa_XTi_2-X(PO₄)₃ was successfully produced in all cases. However, a GaPO₄ impurity was formed due to the high sintering temperatures and high Ga content. The crystallinity of Li_1+XGa_XTi_2-X(PO₄)₃ increased with the sintering temperature as evidenced by FE-SEM observations, which demonstrated that the edges of the larger cube-shaped grains become sharper with increases in the sintering temperature. In samples with high sintering temperatures at 1,000 ℃ and high Ga content above 0.3, coarsening of grains occurred. This resulted in the formation of many grain boundaries, leading to low sinterability. These two factors, the impurity and grain boundary, have an enormous impact on the properties of Li_1+XGa_XTi_2-X(PO₄)₃. The Li_1.3Ga_0.3Ti_1.7(PO₄)₃ pellet sintered at 900 ℃ was denser than those sintered at other conditions, showing the highest total ion conductivity of 7.66 × 10^-5 S/cm at room temperature. The total activation energy of Li-ion transport for the Li_1.3Ga_0.3Ti_1.7(PO₄)₃ solid-state electrolyte was estimated to be as low as 0.36 eV. Although the Li_1+XGa_XTi_2-X(PO₄)₃ sintered at 1,000 ℃ had a relatively high apparent density, it had less total ionic conductivity due to an increase in the grain-boundary resistance with coarse grains.

• The Korean Journal of Nuclear Medicine
• /
• v.34 no.1
• /
• pp.82-93
• /
• 2000

Purpose: We characterized the signals obtained from the components of a small gamma camera using Nal(Tl)-position sensitive photomultiplier tube (PSPMT) and optimized the parameters employed in the modules of the system. Materials and Methods: The small gamma camera system consists of a Nal(Tl) crystal ($60{\times}60{\times}6mm^3$) coupled with a Hamamatsu R3941 PSPMT, a resister chain circuit, preamplifiers, nuclear instrument modules (NIMs), an analog to digital converter and a personal computer for control and display. The PSPMT was read out using a resistive charge division circuit which multiplexes the 34 cross wire anode channels into 4 signals (X+, X-, Y+, Y -). Those signals were individually amplified by four preamplifiers and then, shaped and amplified by amplifiers. The signals were discriminated and digitized via triggering signal and used to localize the position of an event by applying the Anger logic. The gamma camera control and image display was performed by a program implemented using a graphic software. Results: The characteristics of signal and the parameters employed in each module of the system were presented. The intrinsic sensitivity of the system was approximately $8{\times}10^3$ counts/sec/${\mu}Ci$. The intrinsic energy resolution of the system was 18% FWHM at 140 keV. The spatial resolution obtained using a line-slit mask and $^{99m}Tc$ point source were, respectively, 2.2 and 2.3 mm FWHM in X and Y directions. Breast phantom containing $2{\sim}7mm$ diameter spheres was successfully imaged with a parallel hole collimator. The image displayed accurate size and activity distribution over the imaging field of view Conclusion: We proposed a simple method for development of a small gamma camera and presented the characteristics of the signals from the system and the optimized parameters used in the modules of the small gamma camera.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.30 no.1
• /
• pp.132-142
• /
• 2003

This study is performed to investigate the characteristics of the palatal morphology of the children with anterior crossbite in Hellman dental age IIIA by 3-dimensional laser scanner. Totally 40 study casts were taken; 20 were from children with crossbite and another 20 were from normal occlusion as a control. Each cast was scanned by 3 dimension laser scanner and shaped by the 3 dimension image by rapidform 2000 program(INUS, Korea). And finally it was calculated by Rhino 3D program(Rhinoceros, USA). The intercanine, intermolar cross-sectioned transverse plane and sagittal plane were measured. Due to the variations in palatal morphology, each group was standardized into 25mm, 35mm, 35mm. By sectioning standardized curves of the Palatal morphology per 1mm, the palatal depth of each point was calculated. Through these complex methods, the mean curves of the palatal morphology could be obtained and the values were statistically compared and evaluated by T-test with 95% of significance level. The results were as follows: 1. In the intercanine cross-sectioned transverse plane, the mean curve of palatal morphology of crossbite group was flatter V shape than that of control group, however, there was no statistical significance was found between two groups(P>0.05). 2. In the intermolar cross-sectioned transverse plane, the mean curve of palatal morphology of crossbite was deeper all over the area than that of control group, and the statistical significance was found in the middle area from point 8 to 21(P<0.05). 3. In the sagittal plane, the mean curve of palatal morphology of crossbite group was more deepening as approaching posteriorly than that of control group, and the statistical significance was found in all over the area(P<0.01).

• Applied Biological Chemistry
• /
• v.43 no.2
• /
• pp.86-94
• /
• 2000

In order to develop the enzymatic hydrolysis system concerned with taste and flavor, strains having the high hydrolyzing activity on the soy protein were selected from some traditional Mejus. Two molds and one bacterium producing enzymes which were different in character of hydrolysis were isolated and identified. Leucine and azodye enzyme activities of both M4 and M5 were relatively high among in the isolated molds. And, leucine enzyme activity of B16 was the lowest in the isolated bacteria. These strains were isolated as microorganisms having a dissimilar hydrolysis pattern on the soy protein by enzymatic reactions. Mold M4 on the culture solid media was mycelium colors of white and its sclerotia colors were changed from white to black. According to the result of slide culture, radial conidial head, subclavate vesicle, conidia of subglobose, stipes of uncolored with smooth walls and metula and phialides were existed. Because M4 was taxonomically similar to the characteristics of Aspergillus oryzae (ahlburg) species, M4 was identified and named as Aspergillus oryzae M4.Mold M5 showed white and black mycelium on the MEA medium. Mold M5 colony exhibited grayish-green color and have long(7 mm) sporangiophores at slide culture. Sporangia became brownish-gray and the wall of larger sporangia was broken to form small collars, and smaller sporangia were fomed continually from large basal membrane. Columella is globose and hyaline, and sporangiospores are ellipsoidal of small diameter$(80\;{\mu}m)$. Because M5 was taxonomically similar to the Mucor circinelloides of zygomycetes, M5 was was identified and named as Mucor circinelloides M5. Bacteria B16 colony was opaque white, circular and lobate, and had rod shaped endospore. B16 was found positive in stain, catalase, ${\beta}-glucosidse$ and V-P tests. B16 was found to utilize D-fructose, ${\alpha}-D-glucose$, maltose, D-mannose, D-raffinose, stachyose and sucrose. By the morphological and physiological results, the characteristics of B16 was thought to correspond to that of Bacillus megaterium. However, fatty acid composition was similar to Paenibacillus marcerans, requiring further study for the definite identification. Accordingly, Bacteria B16 was provisionally classified and named as Bacillus megaterium B16.

• Restorative Dentistry and Endodontics
• /
• v.22 no.1
• /
• pp.1-33
• /
• 1997

The objective of this study was to analyze the in vitro and in vivo corrosion products of low and high copper amalgams. The four different types of amalgam alloy used in this study were Fine cut, Caulk spherical, Dispersalloy, and Tytin. After each amalgam alloy and Hg were triturated according to the directions of the manufacturer by means of the mechanical amalgamator(Amalgam mixer. Shinhung Co. Korea), the triturated mass was inserted into a cylindrical metal mold which was 12mm in diameter and 10mm in height. The mass was condensed by 150Kg/cm compressive force. The specimen was removed from the mold and aged at room temperature for about seven days. The standard surface preparation was routinely carried out by emery paper polishing under running water. In vitro amalgam specimens were potentiostatically polarized ten times in a normal saline solution at $37^{\circ}C$(potentiostat : HA-301. Hukuto Denko Corp. Japan). Each specimen was subjected to anodic polarization scan within the potential range -1700mV to+400mV(SCE). After corrosion tests, anodic polarization curves and corrosion potentials were obtained. The amount of component elements dissolved from amalgams into solution was measured three times by ICP AES(Inductive Coupled Plasma Atomic Emission Spectrometry: Plasma 40. Perkim Elmer Co. U.S.A.). The four different types of amalgam were filled in occlusal and buccal class I cavities of four human 3rd molars. After about five years the restorations were carefully removed after tooth extraction to preserve the structural details including the deteriorated margins. The occlusal surface, amalgam-tooth interface and the fractured surface of in vivo amalgam corrosion products were analyzed. In vivo and in vitro amalgam specimens were examined and analyzed metallographically by SEM(Scanning Electron Microscope: JSM 840. Jeol Co. Japan) and EDAX(Energy Dispersive Micro X-ray Analyser: JSM 840. Jeol Co. Japan). 1. The following results are obtained from in vitro corrosion tests. 1) Corrosion potentials of all amalgams became more noble after ten times passing through the in vitro corrosion test compared to first time. 2) After times through the test, released Cu concentration in saline solution was almost equal but highest in Fine cut. Ag and Hg ion concentration was highest in Caulk spherical and Sn was highest in Dispersalloy. 3) Analyses of surface corrosion products in vitro reveal the following results. a)The corroded surface of Caulk spherical has Na-Sn-Cl containing clusters of $5{\mu}m$ needle-like crystals and oval shapes of Sn-Cl phase, polyhedral Sn oxide phase. b)In Fine cut, there appeared to be a large Sn containing phase, surrounded by many Cu-Sn phases of $1{\mu}m$ granular shapes. c)Dispersalloy was covered by a thick reticular layer which contained Zn-Cl phase. d)In Tytin, a very thin, corroded layer had formed with irregularly growing Sn-Cl phases that looked like a stack of plates. 2. The following results are obtained by an analysis of in vivo amalgam corrosion products. 1) Occlusal surfaces of all amalgams were covered by thick amorphous layers containing Ca-P elements which were abraded by occlusal force. 2) In tooth-amalgam interface, Ca-P containing products were examined in all amalgams but were most clearly seen in low copper amalgams. 3) Sn oxide appeared as a polyhedral shape in internal space in Caulk spherical and Fine cut. 4) Apical pyramidal shaped Sn oxide and curved plate-like Sn-Cl phases resulted in Dispersalloy. 5) In Tytin, Sn oxide and Sn hydroxide were not seen but polyhedral Ag-Hg phase crystal appeared in internal space which assumed a ${\beta}_l$ phase.

• Restorative Dentistry and Endodontics
• /
• v.26 no.4
• /
• pp.332-340
• /
• 2001

Flowable composite resin has lower filler content, increased flow, and lower modules of elasticity. It is suggested that flowable composite resin can be bonded to the tooth structure intimately and absorb or dissipate the stress. Therefore, it may be advantageous to use flowable composite resin for the base material of class II restoration and for the class V restoraton. The purpose of this study was to evaluate the microleakage and shear bond strength of four flowable composite resins (Aeliteflo, Flow-It, Revolution, Ultraseal XT Plus) compared to Z100 using Scotchbond Multi Purpose dentin bonding system. To evaluate the microleakage, notch-shaped class V cavities were prepared on buccal and lingual surfaces of 80 extracted human premolars and molars on cementum margin. The teeth were randomly divided into non-thermocycling group (group 1) and thermocycling group (group 2) of 40 teeth each. The experimental teeth of each group were randomly divided onto five subgroups of eight samples (sixteen surfaces). The Scotchbond Multi-Purpose and composite resin were applied for each group following the manufacturer's instructions. the teeth of group 2 were thermocycled five hundred times between 5$^{\circ}C$ and 55$^{\circ}C$. The teeth of group 2 were placed in 2% methylene blue dye for 24 hours, then rinsed with tab water. The specimens were embedded in clear resin, and sectioned longitudinally with a diamond saw. The dye penetration on each of the specimen were observed with a stereomicioscope at $\times$20 magnification. To evaluate the shear bond strength, 60 teeth were divided into five groups of twelve teeth each. The experimental teeth were ground horizontally below the dentinoenamel junction, so that no enamel remained. After applying Scotchbond Multi-Purpose on the dentin surface, composite resin was applied in the shape of cylinder. The cylinder was 4mm in diameter and 2mm in thickness. Shear bond strength was measured using Instron with a cross-head speed of 0.5mm/min. After shear bond strength measurement, mode of failure was evaluated with a stereomicroscope at $\times$30 magnification. All data were statistically analyzed by One Way ANOVA and Student-Newman-Keuls method. The correlation between microleakage and shear bond strength was analyzed by linear regression. The results of this study were as follows ; 1. In non-thermocycling group, the leakage value of Z100 was significantly lower than those of flowable composite resins at the enamel and dentin margin, margin, except that Revolution showed the lower leakage value than that of Z100 at the dentin margin (p<0.05). 2. In thermocycling group, the leakage values of Z100 and Ultraseal XT Plus were lower than those of other subgroup at the enamel and dentin margin, except that Flow-It showed the lower leakage value than that of Ultraseal XT Plus at the dentin margin (p<0.05). 3. The leakage value of Z100 and Ultraseal XT Plus in thermocycling group were not higher than that in non-thermocycling group at the enamel margin. The leakage value of Z100 in thermocycling group was not higher than that in non-thermocycling group at the dentin margin (p<0.05). 4. As for the shear bond strength measurement, there were no statistically significant differences among groups (p<0.05). The shear bond strengths given in descending order were as follows: Z100(16.81$\pm$2.98 MPa), Flow-It(14.8$\pm$4.43 MPa), Aeliteflo(14.34$\pm$3.69 MPa), Revolution(13.46$\pm$4.23 MPa), Ultraseal XT Plus(12.83$\pm$3.16 MPa). 5. Failure modes of all specimens were adhesive failures. 6. There was no correlation between microleakage and shear bond strength.

• Journal of the Korean Society of Costume
• /
• v.5
• /
• pp.41-63
• /
• 1981

The mural portraits of the ancient Dukheungri tombs are very important for the study of our traditional costume because the tomb contains a stone. with the in-scription of the date of its erection, 408 A.D. and the name, and official status of the buried. The costumes shown in the mural paintings will be the basis on which historical research can be made concerning costumes before and after 400 A. D. The costume in the mural paintings is classified into five different categories; You (jacket), Po (overcoat), Go (trousers), Sang (skirt), and Gwan (hat). Comparing these categories with those of other mural paintings lead us to the following conclusions. 1. The length of the You (jacket) reaches below the buttocks and the sleeves are narrow. The edges of the sleeves are decorated with stripes. The You (jacket) over-laps on the right, center, and left sides, and there are many Jikryong (V-collar) and Danryong (rounded collar) styles, but it has a similar tendency to others of the Pyongyang area which exhibit many foreign influences. In a departure from tradition. the belts on the men's You (jackets) have only 3 knots in the front, with the back having more knots than the front. The belts of the women's You (jacket) seem to have had a band or button for fastening. We must re-evaluate the assumption that the You (jacket) and Go (trousers) of the northern peoples had the common characters of a belted You (jacket) and Po (over-coat) and that the Gorum originated from the Goryo or Unified Silla dynasty. The outside of the sleeves are longer and more to the side than the inner garment (underwear) so that the sleeves of the inner garment frequently overlapped the outer dress. The above mentioned facts have lead to the discovery of the "Hansam," "Tosi" and "Geodoolgi." 2. The Po (overcoat) was used only by the upperclasses and differs from those found in other mural tombs. The Po (overcoat) of the noble on the tomb mural is centered with an overlapping Jikryong (V-collar) while the other Po (overcoats) of the upperclasses are characterized by an overlap on the left, a Danryong (rounded collar) with two types of sleeves (wide and narrow). Foreign influences and traditional influences coexist in Po (overcoat). Belts have frontal knots without exceptions. The facts that the belts on the You (jackets) are on the front and the belts on the Po (overcoats) are on the back must be reexamined. 3. Go (trousers) is usually narrow, being wider in the rear and narrower below the knees. They were used by hunters on the back of horses with similar Go (trousers) from the Noinwoowha tombs being typical of the northern peoples. 4. Sang (skirts) are pleated as commonly seen in the Goguryo murals. The size of the pleat is varied, each pleat being characteristically wider and having different colors. Same types of pleat are discovered in Central Asia and China. It is uncertain whether the pleat of Goguryo was originated in Central Asia and China or only interrelated with those of the areas. 5. There are three kinds of Gwan (hats); Nagwan, Chuck, and Heukgun. Nag-wan was worn by the dead lords and their close relations. Chuck has three cone shaped horns. Heukgun was worn by military bandmen and horsemen. There are two kinds of hair styles. The up-style was used by the upperclass people closely related to lords, and other people used the Pungimoung hair style. The hair styles of the men and women are characterized by the Pungimoung style. which is a Chinese influence, but still retain their originality. The costume has a similar tendency from those from Yaksuri mural tombs, Anak No. 2 and Anak No. 3. We need to reexamine the costumes from $4{\sim}5$ century murals according to the Dukheungri murals. The costumes of Goguryo share many common factors with those of Western Asia, Central Asia and Ancient China (Han). It seems due to the cultural exchanges among the Northern peoples, the Western and Central Asians, and the Ancient Chinese. It may have resulted from the structural identity or morphological identity of the peoples, or their common social and natural environments and life styles. It will be very valuable to study the costumes of Japan, China, and Korea to find out the common factors. It is only regretful that the study is not based on direct observations but reported information made by 77 persons, because Dukheungri is an off-limits area to us.

• Korean Journal of Mineralogy and Petrology
• /
• v.36 no.4
• /
• pp.273-288
• /
• 2023

The Gubong Au-Ag deposit, which has been one of the largest deposits (Unsan, Daeyudong, Kwangyang) in Korea, consists of eight lens-shaped quartz veins (a mix of orogenic-type and intrusion-related types) that filled fractures along fault zones within Precambrian metasedimentary rock. Korea Mining Promotion Corporation found a quartz vein (referred to as the No. 6 vein with a grade of 27.9 g/t Au and a width of 0.9 m) at a depth of -728 ML by drilling (No. 90-12) conducted in 1989. Korea Mining Promotion Corporation conducted drilling (No. 04-1) in 2004 to investigate the redevelopment's possibility of the No. 6 vein. The author studied the occurrence and chemical composition of chlorite and white mica using wallrock, wallrock alteration and quartz vein samples collected from the No. 04-1 drilling core in 2004. The alteration of studied samples occurs chloritization, sericitization, silicification and pyritization. Chlorite and white mica from mineralized zone at a depth of -275 ML occur with quartz, K-feldspar, calcite, rutile and pyrite in wallrock alteration zone and quartz vein. Chlorite and white mica from ore vein (No. 6 vein) at a depth of -779 ML occur with quartz, calcite, apatite, zircon, rutile, ilmenite, pyrrhotite and pyrite in wallrock alteration zone and quartz vein. Chlorite from a depth of -779 ML has a higher content of Al and Mg elements and a lower content of Si and Fe elements than chlorite from a depth of -275 ML. Also, Chlorites from a depth of -275 ML and -779 ML have higher content of Si element than theoretical chlorite. Compositional variation in chlorite from a depth of -275 ML was mainly caused by phengitic or Tschermark substitution [Al^{3+,VI + Al3+,IV} <-> (Fe²⁺ or Mg²⁺)^VI + (Si⁴⁺)^IV], but compositional variation from a depth of -779 ML was mainly caused by octahedral Fe²⁺ <-> Mg²⁺ (Mn²⁺) substitution. The interlayer cation site occupancy (K+Na+Ca+Ba+Sr = 0.76~0.82 apfu, 0.72~0.91 apfu) of white mica from a depth of -275 ML and -779 ML have lower contents than theoretical dioctahedral micas, but octahedral site occupancy (Fe+Mg+Mn+Ti+Cr+V+Ni = 2.09~2.13 apfu, 2.06~2.14 apfu) have higher contents than theoretical dioctahedral micas. Compositional variation in white mica from a depth of -275 ML was caused by phengitic or Tschermark substitution [(Al³⁺)^VI + (Al³⁺)^IV <-> (Fe²⁺ or Mg²⁺)^VI + (Si⁴⁺)^IV], illitic substitution and direct (Fe³⁺)^VI <-> (Al³⁺)^VI substitution. But, compositional variation in white mica from a depth of -779 ML was caused by phengitic or Tschermark substitution [(Al³⁺)^VI + (Al³⁺)^IV <-> (Fe²⁺ or Mg²⁺)^VI + (Si⁴⁺)^IV] and direct (Fe³⁺)^VI <-> (Al³⁺)^VI substitution.

• Korean Journal of Weed Science
• /
• v.30 no.1
• /
• pp.1-16
• /
• 2010

This study was conducted to develope identification method with major broad leaved weed seedlings. Characteristics of weed seedlings were investigated at two to four true leaf stage. Qualitative characteristics were more useful to identification of weed species than quantitative characteristics at the seedling stage. Many species were elliptic and broadly elliptic type in their cotyledon shape. Cotyledon shape of Cassia nomame and Calystegia sepium were broadly oblong. Four species were transverse broadly elliptic in their cotyledon shape. Rumex japonicus, Persicaria hydropiper, Euphorbia supina and Acalypha australis have three or more types in their cotyledon shape. Cotyledons of Vigna angularis var. nipponensis remained below ground after its germination. Many species were round in apex and were cuneate in base of cotyledon. Humulus japonicus and Polygonum aviculare were sessile in cotyledon base. The second true leaf shape of some species changed after first leaf stages. Glycine soja, V. angularis var. nipponensis and Kummerowia striata were broadly ovate, heart-shaped, orbicular or broadly obovate in their first true leaf, respectively, but the second true leaf shape of them were tripalmately compound. Aeschynomene indica and Cassia nomame were paripinnately compound leaf in their first and second true leaves. Margin of true leaves were entire in many species but six species including Xanthium occidentale were dentate in their true leaf margins. Margin of Euphorbia supina was entire in first true leaf and dentate in second true leaf. Margin of Chenopodium album and C. serotinum were entire in their first true leaf stage and erose in their second true leaf stage. The key for weed seedling identification of major weed species were made based on quantitative and qualitative morphological characteristics.