• Journal of KIISE:Software and Applications
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• v.28 no.9
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• pp.634-648
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• 2001

Message Sequence Charts(MSC) has been used to describe the interactions of numerous concurrent tasks in telecommunication software. After the MSC specification is verified in requirement analysis phase, it can be used not only to synthesize state-based design models, but also to generate test sequences. Until now, the verification is accomplished by generating global state transition graph using the location information only. In this paper, we extend the condition statement of MSC to describe the activation condition of scenarios and the change of state variables, and propose an approach to construct global finite state machine (GFSM) using this information. The GFSM only includes feasible states and transitions of the system. We can generate the test sequences using the existing FSM-based test sequence generation technology.

• Journal of the Korean Ceramic Society
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• v.51 no.2
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• pp.72-81
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• 2014

The main mineral phases of natural hydraulic lime (NHL) as a hydraulic lime binderare $Ca(OH)_2$, $C_2S$, $C_3S$, $C_3A$, and $SiO_2$ residues. Also, NHL has the characteristic of setting and hardening by a hydration reaction with water and by carbonation reactions with carbon dioxide from the air. In this study, in an effort to investigate changes of the mineral phases by NHL hydration and carbonation reactions, transitions of mineral phases and the microstructures of hardened pastes were analyzed by XRD, DSC, SEM, and by pore size distributions using domestic and foreign-sourced NHL pastes after curing at 1, 3, 7, and 28 days. On the basis of the analysis results, it was confirmed that domestic low-grade limestone can be used for the manufacturing of NHL. The main hydration mineral phases were $Ca(OH)_2$, $CaCO_3$, $C_2S$, and $SiO_2$ residues, while in the case of foreign-sourced NHL, a small amount of an aluminium hydration phase formed. Also, the $CaCO_3$ content after the carbonation reaction increased with an increase in the curing time. After hydration for 28 days, NHL containing considerable amounts of $C_2S$ and $C_3S$ showed higher carbonation ratios than others types.

• Journal of the Korean Vacuum Society
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• v.14 no.4
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• pp.238-244
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• 2005

IZO thin films are prepared on a corning 7059 glass substrate in a mixed gases of Ar +$O_2$ by rf-magnetron sputtering, using a powder target with a composition ratio of $In_{2}O_{3}$ : ZnO=90 : 10 $wt.\%$. Their electrical sheet resistance are strongly dependent on the oxygen concentration introduced during the deposition, a minimum resistivity of $3.7\times10^{-4}\Omega\cdot$ cm and an average transmittance over $85\%$ in the visible range are obtained in a film deposited in pure Ar gas which is close to near the stoichiometry. During the heat treatment from room temperature up tp $600^{\circ}C$ in various environments, the electrical resistance changes are explained by cyrstallizations or oxidizations of In metal and InO contained in the IZO film. The electrical properties due to oxygen adsorption and phase transitions occurring at temperatures over $40000^{\circ}C$ during heat treatment in air are also investigated.

• Mass Spectrometry Letters
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• v.8 no.2
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• pp.23-28
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• 2017

Arctigenin is the main active ingredient of Fructus Arctii, which has been reported with a variety of therapeutic activities including anti-cancer, anti-inflammation, anti-virus, and anti-obesity effects. In this study, a simple and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of arctigenin in rat plasma. The assay utilized a simple protein precipitation with methanol and the mobile phase consisted of 100% methanol and water containing 0.1% formic acid (65:35 v/v). Arctigenin and the internal standard (psoralen) were monitored using a positive electrospray turbo ionspray mode with multiple reaction monitoring transitions of m/z $373.2{\rightarrow}136.9$ and m/z $187.2{\rightarrow}130.9$, respectively, and total chromatographic run time was within 5 min. The lower limit of quantification (LLOQ) of arctigenin was 5 ng/mL in the rat plasma. The intra- and inter-day accuracy of arctigenin at LLOQ and matrix-matched quality control samples ranged 97.4 - 104.8% and 97.2 - 102.0%, respectively. The intra-day precision was within 4.80% and the inter-day precision was within 5.92%. Application of the present method was demonstrated through a pharmacokinetic study after intravenous and oral administration of arctigenin in male Sprague Dawley rats.

• Bulletin of the Korean Chemical Society
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• v.19 no.1
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• pp.39-44
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• 1998

$LiCoO_2$ powder was synthesized in an aqueous solution by a sol-gel method and used as a cathode active material for a lithium ion rechargeable battery. The layered $LiCoO_2$ powders were prepared by igniting in air for 12 hrs at 600 ℃ $(600-LiCoO_2)$ and 850 ℃ $(850-LiCoO_2)$. The structure of the $LiCoO_2$ powder was assigned to the space group R bar 3 m (lattice parameters a=2.814 Å and c=14.04Å). The SEM pictures of $600-LiCoO_2$ revealed homogeneous and fine particles of about 1 μm in diameter. Cyclic voltammograms (CVs) of $600-LiCoO_2$ electrode displayed a set of redox peaks at 3.80/4.05 V due to the intercalation/deintercalation of the lithium ions into/out of the $LiCoO_2$ structure. CVs for the $850-LiCoO_2$ electrode had a major set of redox peaks at 3.88/4.13 V, and two small set of redox peaks at 4.18/4.42 V and 4.05/4.25 V due to phase transitions. The initial charge-discharge capacity was 156-132 mAh/g for the $600-LiCoO_2$ electrode and 158-131 mAh/g for the $850-LiCoO_2$ electrode at the current density of 0.2 mA/cm2. The cycleability of the cell consisting of the $600-LiCoO_2$ electrode was better than that of the $850-LiCoO_2$. The diffusion coefficient of the $Li^+$ ion in the $600-LiCoO_2$ electrode was calculated as $4.6{\times}10^{-8}\; cm^2/sec$.

• Journal of the Mineralogical Society of Korea
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• v.31 no.4
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• pp.277-285
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• 2018

Azurite ($Cu_3(CO_3)_2(OH)_2$) was compressed up to 21.52 GPa for its behaviors at ambient temperature. High pressure experiment was performed using the symmetrical diamond anvil cell employed in the angle dispersive X-ray diffraction method. Pressure was determined by ruby fluorescence calibration method. No phase transitions were observed within the present pressure limit and bulk modulus was determined to be 54.4 GPa when ${K_0}^{\prime}$ is fixed to be 4. Applying the normalized pressure-strain analysis, reliability of the azurite compression pattern was checked.

• Biomolecules & Therapeutics
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• v.27 no.2
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• pp.193-200
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• 2019

Ceramide metabolism is known to be an essential etiology for various diseases, such as atopic dermatitis and Gaucher disease. Glucosylceramide synthase (GCS) is a key enzyme for the synthesis of glucosylceramide (GlcCer), which is a main ceramide metabolism pathway in mammalian cells. In this article, we developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to determine GCS activity using synthetic non-natural sphingolipid C8-ceramide as a substrate. The reaction products, C8-GlcCer for GCS, could be separated on a C18 column by reverse-phase high-performance liquid chromatography (HPLC). Quantification was conducted using the multiple reaction monitoring (MRM) mode to monitor the precursor-to-product ion transitions of m/z $588.6{\rightarrow}264.4$ for C8-GlcCer at positive ionization mode. The calibration curve was established over the range of 0.625-160 ng/mL, and the correlation coefficient was larger than 0.999. This method was successfully applied to detect GCS in the human hepatocellular carcinoma cell line (HepG2 cells) and mouse peripheral blood mononuclear cells. We also evaluated the inhibition degree of a known GCS inhibitor 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) on GCS enzymatic activity and proved that this method could be successfully applied to GCS inhibitor screening of preventive and therapeutic drugs for ceramide metabolism diseases, such as atopic dermatitis and Gaucher disease.

• International Journal of Computer Science & Network Security
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• v.23 no.5
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• pp.21-32
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• 2023

The design of complex man-made systems mostly involves a conceptual modeling phase; therefore, it is important to ensure an appropriate analysis method for these models. A key concept for such analysis is the development of a diagramming technique (e.g., UML) because diagrams can describe entities and processes and emphasize important aspects of the systems being described. The analysis also includes an examination of ontological concepts such as states and events, which are used as a basis for the modeling process. Studying fundamental concepts allows us to understand more deeply the relationship between these concepts and modeling frameworks. In this paper, we critically analyze the classic definition of a state utilizing the Thinging machine (TM) model. States in state machine diagrams are considered the appropriate basis for modeling system behavioral aspects. Despite its wide application in hardware design, the integration of a state machine model into a software system's modeling requirements increased the difficulty of graphical representation (e.g., integration between structural and behavioral diagrams). To understand such a problem, in this paper, we project (create an equivalent representation of) states in TM machines. As a case study, we re-modeled a state machine of an assembly line system in a TM. Additionally, we added possible triggers (transitions) of the given states to the TM representation. The outcome is a complicated picture of assembly line behavior. Therefore, as an alternative solution, we re-modeled the assembly line based solely on the TM. This new model presents a clear contrast between state-based modeling of assembly line behavior and the TM approach. The TM modeling seems more systematic than its counterpart, the state machine, and its notions are well defined. In a TM, states are just compound events. A model of a more complex system than the one in the assembly line has strengthened such a conclusion.

• Journal of Sensor Science and Technology
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• v.32 no.3
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• pp.140-146
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• 2023

Water quality is crucial for human health and the environment. Accurate measurement of the quantity of organic carbon in water is essential for water quality evaluation, identification of water pollution sources, and appropriate implementation of water treatment measures. Total organic carbon (TOC) analysis is an important tool for this purpose. Although other methods, such as chemical oxygen demand (COD) and biochemical oxygen demand (BOD) are also used to measure organic carbon in water, they have limitations that make TOC analysis a more favorable option in certain situations. For example, COD requires the use of toxic chemicals, and BOD is time-consuming and can produce inconsistent and unreliable results. In contrast, TOC analysis is rapid and reliable, providing accurate measurements of organic carbon content in water. However, common methods for TOC analysis can be complex and energy-intensive because of the use of high-temperature heaters for liquid-to-gas phase transitions and the use of acid, which present safety risks. This study focuses on a TOC analysis method using TiO₂ photocatalysis, which has several advantages over conventional TOC analysis methods, including its low cost and easy maintenance. For TiO₂, rutile and anatase powders are mixed with an inorganic binder and spray-coated onto a glass fiber substrate. The TiO₂ powder and inorganic binder solutions are adjusted to optimize the photocatalytic reaction performance. The TiO₂ photocatalysis method is a simple and low-power approach to TOC analysis, making it a promising alternative to commonly used TOC analysis methods. This study aims to contribute to the development of more efficient and cost-effective approaches for water quality analysis and management by exploring the effectiveness and reliability of the developed equipment.

• Journal of Ecology and Environment
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• v.47 no.2
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• pp.49-62
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• 2023

Background: Over the past three decades, gradual eustatic sea-level rise has been considered a primary exogenous factor in the increased frequency of flooding and biological changes in several salt marshes. Under this paradigm, the potential importance of short-term events, such as ocean storminess, in coastal hydrology and ecology is underrepresented in the literature. In this study, a simulation was developed to evaluate the influence of wind waves driven by atmospheric oscillations on sedimentary and vegetation dynamics at the Skallingen salt marsh in southwestern Denmark. The model was built based on long-term data of mean sea level, sediment accretion, and plant species composition collected at the Skallingen salt marsh from 1933-2006. In the model, the submergence frequency (number yr^-1) was estimated as a combined function of wind-driven high water level (HWL) events (> 80 cm Danish Ordnance Datum) affected by the North Atlantic Oscillation (NAO) and changes in surface elevation (cm yr^-1). Vegetation dynamics were represented as transitions between successional stages controlled by flooding effects. Two types of simulations were performed: (1) baseline modeling, which assumed no effect of wind-driven sea-level change, and (2) experimental modeling, which considered both normal tidal activity and wind-driven sea-level change. Results: Experimental modeling successfully represented the patterns of vegetation change observed in the field. It realistically simulated a retarded or retrogressive successional state dominated by early- to mid-successional species, despite a continuous increase in surface elevation at Skallingen. This situation is believed to be caused by an increase in extreme HWL events that cannot occur without meteorological ocean storms. In contrast, baseline modeling showed progressive succession towards the predominance of late-successional species, which was not the then-current state in the marsh. Conclusions: These findings support the hypothesis that variations in the NAO index toward its positive phase have increased storminess and wind tides on the North Sea surface (especially since the 1980s). This led to an increased frequency and duration of submergence and delayed ecological succession. Researchers should therefore employ a multitemporal perspective, recognizing the importance of short-term sea-level changes nested within long-term gradual trends.