• Journal of Korean Society of Forest Science
• /
• v.81 no.2
• /
• pp.124-138
• /
• 1992

This study was carried out to estimate long-term demand functions, and to project consumption of roundwood to the year 2030, using time series data for the period 1970-1990. Especially, the unique features of this study are in the estimation of demand functions for roundwood by species group and by end-use with help of dummy variables. It also, attempts to show how dummy variables can be utilized for improving the estimation result. The result of this study reveals that hardwood roundwood consumption is being substituted by softwood roundwood due to the rapid increase in the relative price of softwood, and this trend is expected to continue in the near future. The consumption of roundwood by mining industry is projected to fall as the coal :mining is expected to decline. The parametric estimates of timber demand function by species group and by end-use indicate that the demand for timber in Korea is more responsive to the performance of domestic economy as a whole, represented by GDP in this study, than to other variables such as own and substitute prices. The effects of population growth and substitute prices could not be determined.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1938-1943
• /
• 2005

Network human-robot interface is an important research topic. In home application, users access the robotic system directly via voice, gestures or through the network. Users explore a system by using the services provided by this system and to some extend users are enable to participate in a service as partners. A service may be provided by a robot, a group of robots or robots and other network connected systems (distributed sensors, information systems, etc). All these services are done in the network environment, where uncertainty such as the unstable network connection, the availability of the partners in a service, exists. Moreover, these services are controlled by several users, accessing at different time by different methods. Our research aimed at solving this problem to provide a high available level, flexible coordination system. In this paper, a multi-agent framework is proposed. This framework is validated by using our new concept of slave agents, a responsive multi-agent environment, a virtual directory facilitator (VDF), and a task allocation system using contract net protocol. Our system uses a mixed model between distributed and centralized model. It uses a centralized agent management system (AMS) to control the overall system. However, the partners and users may be distributed agents connected to the center through agent communication or centralized at the AMS container using the slave agents to represent the physical agents. The system is able to determine the task allocation for a group of robot working as a team to provide a service. A number of experiments have been conducted successfully in our lab environment using Issac robot, a PDA for user agent and a wireless network system, operated under our multi agent framework control. The experiments show that this framework works well and provides some advantages to existing systems.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.434.2-434.2
• /
• 2014

We observe enhanced pH response of solution-gated field-effect transistors (SG-FET) having 1D-2D hybrid channel of vertical grown ZnO nanorods grown on CVD graphene (Gr). In recent years, SG-FET based on Gr has received a lot of attention for biochemical sensing applications, because Gr has outstanding properties such as high sensitivity, low detection limit, label-free electrical detection, and so on. However, low-defect CVD Gr has hardly pH responsive due to lack of hydroxyl group on Gr surface. On the other hand, ZnO, consists of stable wurtzite structure, has attracted much interest due to its unique properties and wide range of applications in optoelectronics, biosensors, medical sciences, etc. Especially, ZnO were easily grown as vertical nanorods by hydrothermal method and ZnO nanostructures have higher sensitivity to environments than planar structures due to plentiful hydroxyl group on their surface. We prepared for ZnO nanorods vertically grown on CVD Gr (ZnO nanorods/Gr hybrid channel) and to fabricate SG-FET subsequently. We have analyzed hybrid channel FETs showing transfer characteristics similar to that of pristine Gr FETs and charge neutrality point (CNP) shifts along proton concentration in solution, which can determine pH level of solution. Hybrid channel SG-FET sensors led to increase in pH sensitivity up to 500%, compared to pristine Gr SG-FET sensors. We confirmed plentiful hydroxyl groups on ZnO nanorod surface interact with protons in solution, which causes shifts of CNP. The morphology and electrical characteristics of hybrid channel SG-FET were characterized by FE-SEM and semiconductor parameter analyzer, respectively. Sensitivity and sensing mechanism of ZnO nanorods/Gr hybrid channel FET will be discussed in detail.

• Clinical and Experimental Reproductive Medicine
• /
• v.40 no.3
• /
• pp.115-121
• /
• 2013

Objective: Letrozole and estradiol valerate are used to treat some hormonally-responsive symptoms and also in modeling of the polycystic ovary syndrome. However, the stereological analysis of the ovary has received less attention. Estimation of the whole ovary volume using the Cavalieri method can be applied in any orientation desired, but estimation of the mean volume of the oocytes requires isotropic uniform random sectioning. Here, a combined method was developed for estimating the parameters. To our knowledge, no comparison has been made of the effects of letrozole and estradiol on the ovary. Methods: Sixty rats were divided into 4 groups receiving estradiol (4 mg/kg), olive oil, letrozole (1 mg/kg), or normal saline. After 21 days, their ovaries were studied. Results: Relative to the control group, the total volume of the ovary and the cortex increased in the letrozole-treated and estradiol-treated rats. In addition, the number of the preantral, antral, and granulosa cells decreased by 43% to 56% in the letrozole- and estradiol-treated rats. On average, a 19% increase was observed in the atretic oocytes of the letrozole-treated and estradiol-treated rats, but the mean oocyte volume decreased by 29% to 44% in letrozole- and estradiol-treated rats. Furthermore, the letrozole-treated rats showed a 5-fold and 7-fold increase in the volume of the cysts and corpus luteum, respectively. A 3-fold increase was found in the volume of both the cysts and corpus luteum in the estradiol group. Conclusion: The structural changes of the ovary were most pronounced in the letrozole-treated animals.

• Journal of Microbiology and Biotechnology
• /
• v.8 no.3
• /
• pp.197-202
• /
• 1998

Aliphatic alkenals having 6 to 13 carbons were evaluated for antifungal activity against Saccharomyces cerevisiae. The activity was gradually increased with chain length, e.g., (E)-2-decenal and (E)-2-undecenal exhibited maximum potency, while (E)-2-dodecenal and (E)-2-tridecenal were completely inactive. Alkenals showed increasing inhibitory activity with chain length, as in the case of antifungal activity, towards glucose-induced medium acidification by the plasma membrane $H^+$-ATPase of S. cerevisiae. The group including (E)-2-nonenal, (E)-2-decenal, and (E)-2-undecenal exhibited maximum potency, but the potency of (E)-2-dodecenal and (E)-2-tridecenal demonstrated a sudden drop with respect to the former group. (E)-2-Nonenal revealed dose-responsive inhibition to the medium acidification and inhibited over 90% at a concentration of 1.25 mM ($175.3{\mu}g$/ml). In contrast to (E)-2-undecenal whose inhibitory efficiency increased with incubation time, inhibition by (E)-2-dodecenal was reversed with time. Of the tested alkenals, (E)-2-heptenal and (E)-2-octenal most highly inhibited ATP hydrolytic activity by the plasma membrane $H^+$ ATPase, while (E)-2-heptenal at 10 mM ($1121.8{\mu}g$/ml) showed an inhibitory efficacy of 93.2%.

• Applied Chemistry for Engineering
• /
• v.30 no.6
• /
• pp.698-706
• /
• 2019

Over the last few decades, there have been a lot of efforts to develop soft actuators, which can be external stimuli-responsive and applied to the human body. In order to fabricate medical soft actuators with a dynamic precision control, the 3D crosslinked poly(acrylic acid) (PAAc)/poly(vinyl alcohol) (PVA)/poly(ethylene glycol) (PEG) hydrogels were synthesized in this study by using a radiation technique without noxious chemical additives or initiators. After irradiation, all hydrogels showed high gel fraction over 75% and the ATR-FTIR spectra indicated that PAAc/PVA/PEG hydrogels were successfully synthesized. In addition, the gel fraction, equilibrium water content, and compressive strength were measured to determine the change in physical properties of PAAc/PVA/PEG hydrogels according to the irradiation dose and content ratio of constituents. As the irradiation dose and amount of poly(ethylene glycol) diacrylate (PEGDA) increased, the PAAc/PVA/PEG hydrogels showed a high crosslinking density and mechanical strength. It was also confirmed that PAAc/PVA/PEG hydrogels responded to electrical stimulation even at a low voltage of 3 V. The bending behavior of hydrogels under an electric field can be controlled by changing the crosslinking density, ionic group content, applied voltage, and ionic strength of swelling solution.

• Korea Trade Review
• /
• v.41 no.2
• /
• pp.1-28
• /
• 2016

The purpose of this study is to identity the relationship between CAGE distance and Korean foreign subsidiaries' social responsibility, which is divided into responsive and strategic activities. The hypothesis is that CAGE distance has positive relationships with subsidiaries' social responsibility to overcome local liabilities of foreignness and acquire social legitimacy. The key findings are as follows. Firstly, culture distance has positive significant impacts on subsidiaries' social responsibility activities. It especially has positive influences on strategic CSR. Secondly, administration distance has no impacts on subsidiaries' social responsibility. Thirdly, geographic distance also has positive impacts on subsidiaries' social responsibility activities, especially on responsive CSR. Lastly, economic distance has significantly negative effects on social responsibility. This empirical study identifies the relationships between cross national distance and subsidiaries' social responsibility. Culture and geographic distance has positive influences on subsidiaries' social responsibility. Market seeking subsidiaries group shows more positive relationship between culture distance and social responsibility activities, which means that foreign subsidiaries would engage in social responsibility activities for strategic purpose.

• Journal of Environmental Science International
• /
• v.20 no.7
• /
• pp.799-809
• /
• 2011

Objectives: This study is aimed at identifying the influential factors on the pulmonary function of ordinary residents in the surrounding areas of Yeosu Industrial Complex. Methods: The PFT (Pulmonary Function Test) was conducted on the target residents numbering 989 people (male 361, female 628). The exposed group (813 people) resided within the radius of 5km from Yeosu Industrial Complex and the control group (176 people) resided in the radius of more than 15 km from May 2007 to November 2007. The survey also took into account other factors including personal characteristics, life habits, respiratory diseases and allergic symptoms, medical histories, and the living environments of the residents in order to further identify influential factors on pulmonary function. Result: When comparing the PFT values of the exposure groups to the control group of the same city, values of the exposure groups were meaningfully lower with an %$FEV_1$ of 107.05% and %FVC of 100.28%. Conversely, the control group reported an %$FEV_1$ and %FVC of 107.26% and 102.85% respectively, indicating that ambient air pollutants reduce lung function. The odds ratio of asthma diagnosis history increased when a subjects residence was close to a heavily trafficked road, traffic amount was huge, a bed was used, and the family had less than four members. However the results were not statistically meaningful. The odds ratios of abnormal pulmonary function were statistically higher among those with asthma(OR=4.29, CI=1.75-10.56), wheezing (OR=2.59, CI=1.24-5.41), and nasal congestion (OR=2.87, CI=1.36-6.08) (p<0.01). The factors affecting $FEV_1$ were symptoms including asthma, passive smoking and allergic eye disease ($R^2$=0.049, p<0.001). For the FVC symptoms including asthma ($R^2$=0.014, p<0.001) were measured. The analysis showed that FVC decreased with increases in $O_3$ and CO(p<0.01). Furthermore, $FEV_1$ decreased with increases in $O_3$(p<0.01). Conclusions: These results will provide preliminary data for establishing responsive measures to protect the health of residents in industrial complexes from air pollution, and to develop lasting environmental health policies.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.27 no.4
• /
• pp.314-320
• /
• 2001

Matrix metalloproteinases have long been viewed as ideal candidates for proteinases that enables tumor cells to permeated basement membrane defenses and invade surrounding tissue. There is growing evidence that the MMPs have an expanded role, as they are important for the creation and maintenance of a microenvironment that facilitates growth and angiogenesis of tumors at primary and metastatic sites. MT-MMPs are not secreted but instead remaining attached to cell surfaces. Although not all of the MT-MMPs are fully characterized, MT-MMPs have important role in localizing and activating secreted MMPs. The MMP genes are transcriptionally responsive to a wide variety of oncogene, growth factors, cytokine, and hormones. Currently, a number of MMP inhibitors are being developed and some have reached clinical trials as anti-metastatic or anti-cancer therapies. MT1-MMP is involved in the activation of proMMP-2. MT1-MMP is significant not only as a tumor marker but as a new target for chemotherapy against cancer. The purpose of this study was to evaluate the effects of protein kinase C inhibitor(genistein) on the proliferation of HT1080 and expression of MT1-MMP mRNA. Human fibrosarcoma cell line HT1080 was cultured and divided 2 groups. The experimental group was treated with $100{\mu}M$ genistein and incubated 12h, 24h for $[3^H]-thymidine$ uptake assay and northern hybridization individually. And the control group was treated with same amount of PBS for the above procedures. $[3^H]-thymidine$ incorporation was measured with ${\beta}$ ray detector. And RT-PCR and northern blotting for MT1-MMP mRNA was performed. The results were as follows 1. $[3^H]-thymidine$ uptake was reduced in experimental group with statistical significance. 2. MT1-MMP mRNA expression was significantly reduced in experimental group. These results showed that protein kinase C inhibitor (genistein) inhibited proliferation of HT1080 and almost completely blocked transcription of MT1-MMP mRNA. So, it is possible to use the protein kinase inhibitor (genistein) as anti-metastatic and anti-proliferative agent.

• Journal of Music and Human Behavior
• /
• v.9 no.1
• /
• pp.21-36
• /
• 2012

The purpose of this study was to examine perceived supervisory satisfaction depending on the type of supervision. Twenty-six music therapy graduate students who enrolled in a practicum course participated in this study. All participants received four individual and four group supervision sessions over the course of the semester. After each supervision session, participants were asked to rate their satisfaction with supervision on the Supervisory Satisfactory Questionnaire(SSQ). Results showed that there was no significant difference in the mean ratings between individual and group supervision conditions, indicating that the type of supervision would not differently affect the perception of overall supervisory satisfaction. However, a detailed analysis of ratings for each questionnaire item and comments from the participants imply that while individual supervision would be perceived to meet supervisees' individual needs more effectively, satisfaction with group supervision would be less influenced by supervisor styles. This study would provide descriptive information of perceived satisfaction with supervision type as an initial trial toward suggesting the systematic approach to the music therapy supervision format. Further studies are needed to investigate how effective and culturally responsive supervision format would be structured to facilitate supervision process and maximize supervision outcome.