• Journal of the Korean earth science society
• /
• v.34 no.4
• /
• pp.345-355
• /
• 2013

While virtual field trips (VFT) are considered as an attractive alternative to traditional field experience, it is unclear how VFT are best used in Earth Science curriculum. In this study, we investigated the effects of flash panorama-based VFT on students' spatial visualization ability and their understanding of volcanic concept in high school Earth Science class. To investigate the effects of instructional treatment, we conducted pre and post-test on participants' spatial visualization ability and their understanding of volcanic concept, and analyzed using analysis of covariance (ANCOVA) and linear regression. Findings are as follows: First, the change in students' spatial visualization ability in experimental group was significantly higher than that of control group, especially in spatial manipulation category. Second, the change in students' understanding of volcanic concept in experimental group was higher than that of control group in most of the categories, but it is statistically not significant. Last, the change in correlation between spatial visualization ability and understanding of volcanic concept in experimental group was remarkably high compared to control group.

• Current Research on Agriculture and Life Sciences
• /
• v.10
• /
• pp.1-9
• /
• 1992

Culture condition for callus formation and plant regeneration were optimized by the selection of explants and the manipulation of hormonal combination in the culture medium. The calli induced from seed, cotyledon, hypocotyl and mesophyll segments were more vigorously proliferated under dark condition than those under continuous light condition. Hypocotyl-and cotyledon-derived calli were more regenerative as compared with those of seed and mesophyll. Callus formation from hypocotyl and cotyledonary explants was enhanced on MS medium with 1.0 mg/${\ell}$ 2, 4-D and 0.1 to 0.5 mg/${\ell}$ kinetin or BAP. The combination of 0.1 mg/${\ell}$ NAA and 2.0 to 4.0 mg/${\ell}$ kinetin was the most effective for shoot regeneration from the callus. The maximum frequency (24.0%) of shoot regeneration was obtained from the hypocotyl-derived callus transferred to MS medium supplemented with 0.1mg/${\ell}$ NAA and 4.0 mg/${\ell}$ kinetin. The capacities for callus, root and shoot formation from cotyledon and hypocotyl explants were remarkably different among cultivars of B. napus tested. The calli induced from hypocotyl produced more shoots than those from cotyledon.

• Current Research on Agriculture and Life Sciences
• /
• v.32 no.1
• /
• pp.1-9
• /
• 2014

In contrast to conventional microwaves, QRD (Quadratic Residue Diffusor) microwaves are a new energy-efficient technology that enhances the effect of sterilization based on changing the wavelength phase difference. Therefore, this study investigated the sterilization of wood using environmentally friendly and low energy consuming QRD microwaves. The results are as follows: for the QRD microwaves used in this study, the efficiency E = 5.75e0.32 S ($R^2$=0.908). Although the early water content was not constant, the average water content was 30.3% and after one week of natural drying, the water content was 22.6%, representing an average water content reduction of about 8%. When increasing the microwave level from 3 kW ~ 9 kW, the time taken for the temperature to increase was reduced. After the QRD microwave treatment, the wood samples showed no change in their flexural rigidity, compressive strength, or cleavage. The QRD microwave levels used in the experiments were 3, 5, 7, and 9 kW, where 9 kW was found to be the most efficient. Thus, for the purpose of eliminating nematodes and termites inside wood, a higher QRD microwave level was found to be more effective and energy efficient.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.11
• /
• pp.641-649
• /
• 2020

This study was conducted to examine the effects of instruction (explicit, implicit) and stimulus presentation time (300 ms, 500 ms) in ABM training. According to the Social Avoidance and Distress Scale (SADS) and the attention bias score (ABS), 60 undergraduate students were selected. All participants' SADS scores were above 82 and their ABS score was greater than 0. The training group was explicit-300 ms training group (n=10), explicit-500 ms training group (n=10), implicit-300 ms training group (n=10) and implicit-500 ms training group (n=10). In the implicit instruction group, only information about procedure was included. In the explicit instruction group, additional information about training manipulation (the probe always presented at the location of the preceding neutral stimuli) was provided. The control group were placebo-300 ms control group(n=10) and placebo-500 ms control group(n=10). After 8 sessions of training, the effect was only found in instruction conditions. The explicit training group showed significantly decreased SADS after training. ABS changed significantly in all three conditions but the treatment effect was most effective in the explicit instruction condition. No significant effect was found in the stimulus presentation time. These results suggest that explicit instruction might promote the effect of ABM training compared to implicit instruction.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.11
• /
• pp.878-883
• /
• 2020

Cryptographic algorithms are used to prevent the illegal manipulation of data. They are divided into public-key cryptosystems and symmetric-key cryptosystems. Public-key cryptosystems require considerable time for encryption and decryption compared to symmetric-key cryptosystem. On the other hand, key management, and delivery are easier for public-key cryptosystems than symmetric-key cryptosystems because different keys are used for encryption and decryption. Furthermore, hash functions are being used very effectively to verify the integrity of the digital content, as they always generate output with a fixed size using the data of various sizes as input. This paper proposes a method using RSA public-key cryptography and a hash function to determine if a digital image is deformed or not and to detect the manipulated location. In the proposed method, the entire image is divided into several blocks, 64×64 in size. The watermark is then allocated to each block to verify the deformation of the data. When deformation occurs, the manipulated pixel will be divided into smaller 4×4 sub-blocks, and each block will have a watermark to detect the location. The safety of the proposed method depends on the security of the cryptographic algorithm and the hash function.

• Journal of Broadcast Engineering
• /
• v.12 no.2
• /
• pp.128-136
• /
• 2007

Since the multi-view video is a set of video sequences captured by multiple array cameras for the same three-dimensional scene, it can provide multiple viewpoint images using geometrical manipulation and intermediate view generation. Although multi-view video allows us to experience more realistic feeling with a wide range of images, the amount of data to be processed increases in proportion to the number of cameras. Therefore, we need to develop efficient coding methods. One of the possible approaches to multi-view video coding is to generate an intermediate image using view interpolation method and to use the interpolated image as an additional reference frame. The previous view interpolation method for multi-view video coding employs fixed size block matching over the pre-determined disparity search range. However, if the disparity search range is not proper, disparity error may occur. In this paper, we propose an efficient view interpolation method using initial disparity estimation, variable block-based estimation, and pixel-level estimation using adjusted search ranges. In addition, we propose a multi-view video coding method based on H.264/AVC to exploit the intermediate image. Intermediate images have been improved about $1{\sim}4dB$ using the proposed method compared to the previous view interpolation method, and the coding efficiency have been improved about 0.5 dB compared to the reference model.

• BMB Reports
• /
• v.47 no.9
• /
• pp.512-517
• /
• 2014

In this study, we showed that Mycobacterium abscessus MAB2560 induces the maturation of dendritic cells (DCs), which are representative antigen-presenting cells (APCs). M. abscessus MAB2560 stimulate the production of pro-inflammatory cytokines [interleukin (IL)-6, tumor necrosis factor (TNF)-${\alpha}$, IL-$1{\beta}$, and IL-12p70] and reduce the endocytic capacity and maturation of DCs. Using $TLR4^{-/-}$ DCs, we found that MAB2560 mediated DC maturation via Toll-like receptor 4 (TLR4). MAB2560 also activated the MAPK signaling pathway, which was essential for DC maturation. Furthermore, MAB2560-treated DCs induced the transformation of $na\ddot{i}ve$ T cells to polarized $CD4^+$ and $CD8^+$ T cells, which would be crucial for Th1 polarization of the immune response. Taken together, our results indicate that MAB2560 could potentially regulate the host immune response to M. abscessus and may have critical implications for the manipulation of DC functions for developing DC-based immunotherapy.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.73-75
• /
• 2013

Atomic force microscopy (AFM) [1] can now not only image individual atoms but also construct atom letters using atom manipulation method [2]. Therefore, the AFM is the second generation atomic tool following the well-known scanning tunneling microscopy (STM). The AFM, however, has the advantages that it can image even insulating surfaces with atomic resolution and also measure the atomic force itself between the tip-apex outermost atom and the sample surface atom. Noting these advantages, we have been developing a novel bottom-up nanostructuring system, as shown in Fig. 1, based on the AFM. It can identify chemical species of individual atoms [3] and then manipulate selected atom species to the designed site one-by-one [2] to assemble complex nanostructures consisted of many atom species at room temperature (RT). In this invited talk, we will introduce our results toward atom-by-atom assembly of composite nanomaterials based on the AFM at RT. To identify chemical species, we developed the site-specific force spectroscopy at RT by compensating the thermal drift using the atom tracking. By converting the precise site-specific frequency shift curves, we obtained short-range force curves of selected Sn and Si atoms as shown in Fig. 2(a) and 2(b) [4]. Then using the atom-by-atom force spectroscopy at RT, we succeeded in chemical identification of intermixed three atom species in Pb/Sn/Si(111)-(${\surd}3$'${\surd}3$) surface as shown in Fig. 2(c) [3]. To create composite nanostructures, we found the lateral atom interchange phenomenon at RT, which enables us to exchange embedded heterogeneous atoms [2]. By combining this phenomenon with the modified vector scan, we constructed the atom letters "Sn" consisted of substitutional Sn adatoms embedded in Ge adatoms at RT as shown in Fig. 3(a)~(f) [2]. Besides, we found another kind of atom interchange phenomenon at RT that is the vertical atom interchange phenomenon, which directly interchanges the surface selected Sn atoms with the tip apex Si atoms [5]. This method is an advanced interchangeable single atom pen at RT. Then using this method, we created the atom letters "Si" consisted of substituted Si adatoms embedded in Sn adatoms at RT as shown in Fig. 4(a)~(f) [5]. In addition to the above results, we will introduce the simultaneous evaluation of the force and current at the atomic scale using the combined AFM/STM at RT.

• The Korean Journal of Cytopathology
• /
• v.7 no.1
• /
• pp.1-11
• /
• 1996

From the concepts of cellular pathology and of exfoliative cytology, as elucidated by Virchow and Papanicolaou respectively in the late 19th and early 20th century, have evolved the primary methods for the diagnosis of cancer today. From Papanicolaou's concept of exfoliative cytology developed fine needle aspiration biopsy in the early 1960's, this has become a major diagnostic procedure and has contributed to a significant reduction in open biopsies and, therefore, to medical cost-effectiveness immunobiochemical techniques provided us with a supplement to cancer diagnosis in the 1980's. The immunoperoxidase method, using monoclonal antibodies, is applied primarily as an ancillary measure to elucidate the nature of cancers The availability of specific monoclonal antibodies has greatly facilitated the identification of cell products or surface markers. For example, antibodies directed against intermediate filaments have proved to be of value in determining the histogenesis oi poorly differentiated neoplasms. Tumor markers may serve as biochemical indicators of the presence of a neoplasm. They can be detected In plasma and other body fluids. Their concentration can be applied as a diagnostic test, for monitoring the clinical course of known cancer, and as a screening measure to detect certain cancers in a population at risk. Flow cytometry is a useful tool for distinguishing several cell characteristics, such as the immunophenotype of leukemia-lymphoma cells, the DNA content of neoplastic cells, and cell proliferation rate. Molecular biologic techniques provided a giant step for the management of cancer patients encompassing diagnosis, prognostic evaluation, and therapy. Nucleic acid hybridization techniques are utilized as Southern, Northern, and dot blots and in situ hybridization. Molecular biology and its techniques may bring a blight new horizon for understanding cancer biology and in designing therapy on the basis of gene manipulation.

• Development and Reproduction
• /
• v.9 no.1
• /
• pp.1-5
• /
• 2005

The hypothalamo-pituitary-gonadal hormone axis is centrally controlled by a complex regulatory network of excitatory and inhibitory signals, that is dormant during infantile and juvenile periods and activated at puberty. The kisspeptins are the peptide products of the KiSS-1 gene and the endogenous agonists for the G protein-coupled receptor 54(GPR54). Although KiSS-1 was initially discovered as a metastasis suppressor gene, a recent evidence suggests the KiSS-1/GPR54 system is a key regulator of the reproductive system. Yet the actual role of the KiSS-1/GPR54 system in the neuroendocrine control of gonadotropin secretion remains largely unexplored, the system could be the first missing link in the reproductive hormonal axis. Central or peripheral administration of kisspeptin stimulates the hypothalamic-pituitary-gonadal axis, increasing circulating gonadotropin levels in rodents, sheep, monkey and human models. These effects appear likely to be mediated via the hypothalamic GnRH neuron system, although kisspeptins may have direct effects on the anterior pituitary gland. The loss of function mutations of the GPR54(GPR54-/-) have been associated with lack of puberty onset and idiopathic hypogonadotropic hypogonadism(IHH). So kisspeptin infusion may provide a novel mechanism for HPG axis manipulation in disorders of the reproductive system.