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Development of a 300W Generator for Lightweight Wind Turbine

  • Lee, Hee-Kune;Lee, Hee-Joon;Kim, Sun-Hyung
    • The Journal of Korean Institute of Information Technology
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    • v.15 no.12
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    • pp.181-188
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    • 2017
  • As a population of leisure activities grows and diversifies, there is a great demand for portable and environment-friendly power generation systems. A small wind power generation system is emerging as a suitable power generation equipment to meet these needs. The most important thing when developing a small portable wind turbine is to reduce the weight of the generator and increase the efficiency. The existing 300W wind turbine generator weighs about 10kg, which is heavy to carry. Therefore, a new generator weighing less than 4kg to make it easy to carry with high efficiency has been developed. In addition, considering complicated characteristics of wind volume and topography of Korea, a small wind turbine that can be used in urban and rural areas individually was constructed. Through basic designing and optimization, the lightweight and efficient generator was manufactured. It is a 300W wind turbine designed and fabricated with reduced weight as a prototype. The average output voltage of the generator was 24.7V at 900rpm no-load test. On a load test with the average line voltage 36.8V and the average phase current 2.62A, when the mechanical input was 339.84W, an average voltage output of the generator was measured as 289.5W with efficiency of 85.18%. The generator weight was 3.84kg.

The Distribution of Indoor Air Pollutants by the Categories of Public-Use Facilities and Their Rate of Guideline Violation (다중이용시설별 실내공기 오염물질 농도분포 및 기준치 이상 값의 구성비 조사)

  • Joen, Jeong-In;Lee, Hye-Won;Choi, Hyun-Jin;Jeon, Hyung-Jin;Lee, Cheolmin
    • Journal of Environmental Health Sciences
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    • v.47 no.5
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    • pp.398-409
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    • 2021
  • Background: The types and effects of hazardous pollutants in indoor air may vary depending on the characteristics of the sources and pollutants caused by physical and chemical properties of buildings, the influence of outdoor air, and the exposure and use characteristics of residents. Objectives: This study was conducted to provide basic data on the establish of indoor air quality management for different classes of public-use facilities by presenting the characteristics of concentration distribution of hazardous pollutants by different public-use facilities and the status of the excess proportion of exceeding standards. Methods: This study analyzed self-measurement data from public-use facilities taken from 2017 to 2019 A total of 133,525 facilities were surveyed. A total of 10 types of pollutants that have maintenance and recommended standards stipulated in the Indoor Air Quality Control Act from the Ministry of Environment were investigated. The excess proportion and the substances exceeding the criteria for each type of public-use facilities for these pollutants were investigated. Results: As a result of the analysis of the proportion of exceeding the standard for each type of public-use facility, the facilities with the highest excess proportion of the standards for each hazardous pollutant were: PM10 in railway stations (8.93%), PM2.5 in daycare centers (7.36%), CO2 in bus terminals (2.37%), HCHO in postpartum care centers (4.11%), total airborne bacteria in daycare centers (0.69%), CO in museums (0.1%), NO2 in postpartum care centers (1.15%), Rn in museums (0.78%), total volatile organic compounds in postpartum care centers (7.20%) and mold in daycare centers (1.44%). Conclusions: Although uncertainty may arise because this study is a result of self-measurement, it is considered that this study has significance for providing basic data on the establishment in the future of indoor air quality management measures customized for each type of public-use facility.

Seasonal Assessment of Groundwater-Dependent Ecosystem Using Monitoring of Benthic Macroinvertebrates in Wetland (계절에 따른 습지 내 저서성대형무척추동물 모니터링을 통한 지하수의존생태계 특성 평가)

  • Jeong, Chanyoung;Choi, Ji-Woong;Moon, Hee Sun;Kim, Dong-Hun;Moon, Sang-Ho;O, Yong-Hwa;Han, Ji Yeon;Oh, Seolran;Kim, Yongcheol
    • Journal of Soil and Groundwater Environment
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    • v.26 no.6
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    • pp.130-143
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    • 2021
  • Wetlands are one of the most representative groundwater dependent ecosystems(GDEs) that require access to groundwater on a permanent or intermittent basis to maintain their biological communities and ecological processes. In this study, the seasonal characteristics of the GDEs in Baekseok Reservoir Wetland were evaluated through the monitoring of the temporal and spatial community of benthic macroinvertebrates in the wetland. The appearance of benthic macroinvertebrates appearance was changed seasonally depending on environmental factors such temperature, precipitation and water level for their habitat and it also showed the clear spatial difference in the wetland. The scores of Diversity index(H'), Richness Index (R1) and the Ecological score of benthic macroinvertebrates (TESB/AESB) were relatively high at St.3 and 4(i.e., north area) where groundwater inflows into wetland(i.e., high 222Rn conc.). The statistical analysis (ANOVA test and PCA) investigated the correlation among the benthic macroinvertebrates' community, groundwater level, wetland water level and water quality. The results showed that the community of benthic macroinvertebrates at St. 3 and 4 in Baekseok Reservoir Wetlands was spatially dependent on groundwater level and groundwater inflow. The characterization and assessment of GDEs requires understanding the hydrological, biogeochemical and biological process and this study will provide information for characterization and assessment of GDEs.

Feeding Habits of Larval Acanthogobius flavimanus from the Nakdong River Estuary, Korea (낙동강 하구역에 출현하는 문절망둑 (Acanthogobius flavimanus) 자치어의 식성)

  • Choi, Hee Chan;Cho, Jeong Hyun;Huh, Sung Hoi;Park, Joo Myun
    • Korean Journal of Ichthyology
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    • v.31 no.3
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    • pp.150-158
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    • 2019
  • We examined the food habits of larval Acanthogobius flavimanus using 260 specimens collected from February to April 2011 in the Nakdong River estuary, Korea. We found that larval A. flavimanus are carnivorous, feeding mainly on copepods and tintinnids. Their diet also included small quantities of larval polychaetes, macrostomids, larval bivalves, rotifers, barnacles, diatoms and unidentified materials. To assess ontogenetic changes in diet composition, the larvae were separated into three developmental stages: preflexion (<7 mmNL), flexion (7~9 mmNL), and postflexion (>9 mmNL). The preflexion group frequently preyed on tintinnids. But as the larvae of A. flavimanus grew, the consumption of copepods for flexion group, and polychaetes for postflexion group, increased respectively. The larvae of A. flavimanus showed one peak for feeding incidence at dusk, but the mean number of preys per individual was high until midnight.

Effect of CEOs' Characteristics on Digital Transformation and Corporate Performance: Focusing on RSN Co., Ltd (최고경영자의 특성이 디지털 전환과 기업성과에 미치는 영향: (주)RSN중심으로)

  • Park, Soohwang;Jang, Kyungbae
    • Journal of Internet of Things and Convergence
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    • v.8 no.3
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    • pp.11-20
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    • 2022
  • Corporations operate within long term strategy. The Chief Executive Officer (CEO) makes decisions and has responsibility for all executive activities which affects the corporate performance. If the CEO makes strategic choices through reasonable decision making, it could affect corporate performance and corporate's rise and fall. So the CEO's decision making is very important. As rapid change in the digital technology environment happened, through digital transition, corporations have been working on increasing corporate performance by practical and academic methods. However prior research was restricted to CEO's affect on organization, innovation or innovative activities and there is a lack of research linking CEO's characteristics to digital transition and corporate performance. As the digital age is coming, research on how CEO's characteristics affect digital transition and corporate performance is direly needed. From the case of domestic Big Data corporation RSN Co. ltd's digital transition success, understanding characteristics of CEO, digital transition and corporate performance through prior researches, and developing research model and research proposition was set. Research was performed on RSN co. ltd's case analysis, and how characteristics of CEO's matter on digital transformation and corporate performance. As a result of the proposition, when the CEO conjugates digital technology, the corporation was able to successfully complete digital transition and it also affects corporate performance. Also, this research's other point is that CEO's may have limits on thoughtful decision making. It is judged that it is necessary to try an empirical study in the future.

Tumor Habitat Analysis Using Longitudinal Physiological MRI to Predict Tumor Recurrence After Stereotactic Radiosurgery for Brain Metastasis

  • Da Hyun Lee;Ji Eun Park;NakYoung Kim;Seo Young Park;Young-Hoon Kim;Young Hyun Cho;Jeong Hoon Kim;Ho Sung Kim
    • Korean Journal of Radiology
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    • v.24 no.3
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    • pp.235-246
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    • 2023
  • Objective: It is difficult to predict the treatment response of tissue after stereotactic radiosurgery (SRS) because radiation necrosis (RN) and tumor recurrence can coexist. Our study aimed to predict tumor recurrence, including the recurrence site, after SRS of brain metastasis by performing a longitudinal tumor habitat analysis. Materials and Methods: Two consecutive multiparametric MRI examinations were performed for 83 adults (mean age, 59.0 years; range, 27-82 years; 44 male and 39 female) with 103 SRS-treated brain metastases. Tumor habitats based on contrast-enhanced T1- and T2-weighted images (structural habitats) and those based on the apparent diffusion coefficient (ADC) and cerebral blood volume (CBV) images (physiological habitats) were defined using k-means voxel-wise clustering. The reference standard was based on the pathology or Response Assessment in Neuro-Oncologycriteria for brain metastases (RANO-BM). The association between parameters of single-time or longitudinal tumor habitat and the time to recurrence and the site of recurrence were evaluated using the Cox proportional hazards regression analysis and Dice similarity coefficient, respectively. Results: The mean interval between the two MRI examinations was 99 days. The longitudinal analysis showed that an increase in the hypovascular cellular habitat (low ADC and low CBV) was associated with the risk of recurrence (hazard ratio [HR], 2.68; 95% confidence interval [CI], 1.46-4.91; P = 0.001). During the single-time analysis, a solid low-enhancing habitat (low T2 and low contrast-enhanced T1 signal) was associated with the risk of recurrence (HR, 1.54; 95% CI, 1.01-2.35; P = 0.045). A hypovascular cellular habitat was indicative of the future recurrence site (Dice similarity coefficient = 0.423). Conclusion: After SRS of brain metastases, an increased hypovascular cellular habitat observed using a longitudinal MRI analysis was associated with the risk of recurrence (i.e., treatment resistance) and was indicative of recurrence site. A tumor habitat analysis may help guide future treatments for patients with brain metastases.

Biostatic activity of Coix lacryma seed extract on Toxoplasma gondii in macrophages (율무씨 수침 추출물이 대식세포내 톡소포자충에 미치는 영향에 관한 실험적 연구)

  • 소진탁;김숙향
    • Parasites, Hosts and Diseases
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    • v.34 no.3
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    • pp.197-206
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    • 1996
  • Water extract of Coix locrvmn seeds (Co-Ex) was separated into several components; dissolved with Tris-Cl buffer and the supernatant (WC 1), ammonium sulfate treatment supernatant (WC2) and the pellet nvc31,9AE column chromatography of WC 1 and the peak portions; WC4, WCS and WC6. Murine peritoneal macrophages in DMEM containing 10% heat-inactivated FCS were infected with tachyzoites of ToxopIQsmc gondii, RH strain, in uifo. By adding modulators such as Co-Ex, WC 1,2,3,4.5,6 and LPS or IFN-γ for 24 hrs . toxoplasmastatic activity of macrophages was examined in relation to nitrite production. Nitrite production of macrophages was enhanced especially in the series of WC2, WC1 and the combination sample (WC1 + WC2 + WC3) by order than other components or fractions (WC4, WC5, WC6) tested . Toxoplasmastatic actions such as percentage of the inacrophages infected by T. gonnii and fold increase of T gondii in macrophages showed retroverse relations with the amount of nitrite production; i.e. as nitric oxide (NO) increased the phagocytic index of macrophages and the fold increase of tachyzoites in macrophages decreased . Nitrite (NO-2) production was increased by adding IFN-γ in all cases together with enhancement of biostatic effects. Through the results obtained, it is speculated that some components other than the non-proteinous and defatted components in Coix lacrwmn seeds may contribute to activate macrophages through induction of NO for the biostatic activity.

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Geochemical Occurrence of Uranium and Radon-222 in Groundwater at Test Borehole Site in the Daejeon area (대전지역 시험용 시추공 지하수내 우라늄 및 라돈-222의 지화학적 산출특성)

  • Jeong, Chan Ho;Ryu, Kun Seok;Kim, Moon Su;Kim, Tae Sung;Han, Jin Suk;Jo, Byung Uk
    • The Journal of Engineering Geology
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    • v.23 no.2
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    • pp.171-186
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    • 2013
  • A drilling project was undertaken to characterize the geochemical relationship and the occurrence of radioactive materials at a test site among public-use groundwaters previously known to have high occurrence of uranium and radon-222 in the Daejeon area. A borehole (121 m deep) was drilled and core rocks mainly consist of two-mica granite, and associated with pegmatite and dykes of intermediate composition. The groundwater samples collected at six different depths in the borehole by a double-packed system showed the pH values ranging from neutral to alkaline (7.10-9.3), and electrical conductivity ranging from 263 to 443 ${\mu}S/cm$. The chemical composition of the borehole groundwaters was of the $Ca-HCO_3(SO_4+Cl)$ type. The uranium and Rn-222 contents in the groundwater were 109-1,020 ppb and 9,190-32,800 pCi/L, respectively. These levels exceed the regulation guidelines of US EPA. The zone of the highest groundwater uranium content occurred at depths of 45 to 55m. The groundwater chemistry in this zone (alkaline, oxidated, and high in bicarbonate) is favorable for the dissolution of uranium into groundwater. The dominant uranium complex in groundwater is likely to be $(UO_2CO_3)^0$ or $(UO_2HCO_3)^+$. Radon-222 content in groundwater shows an increasing trend with depth. The uranium and thorium contents in the core were 0.372-47.42 ppm and 0.388-11.22 ppm, respectively. These levels are higher values than those previously been reported in Korea. Microscopic observations and electron microprobe analysis(EPMA) revealed that the minerals containing U and Th are monazite, apatite, epidote, and feldspar. U and Th in these minerals are likely to substitute for major elements in crystal lattice.

A Study of the Implemented Korean Traditional Garden Design Elements on Tashkent Seoul Park (타슈켄트 서울공원 설계과정에서 구현된 한국정원 설계요소 고찰)

  • Shin, Hyun-Don
    • Journal of the Korean Institute of Landscape Architecture
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    • v.43 no.5
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    • pp.40-54
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    • 2015
  • Tashkent Seoul Park was completed in June, 2014, following the signing of a sisterhood relationship between Seoul City and Tashkent, the capital of Uzbekistan in July, 2010. An open competition for the design of the park was held and, based on the design, the park was completed in June and open to the public in September, 2014. Tashkent Seoul Park is more than a public park in Tashkent. The focus was on making it a starting point for offering a new model for traditional parks of Korea built abroad. Korean gardens and parks built in overseas cities are not only a landscape space but also serve as an ambassador that promotes the culture of Korea to foreigners who are unfamiliar with Korean culture. Therefore, Tashkent Seoul Park was designed to reflect the beauty and uniqueness of Korean traditional landscaping to promote the image of Korea and Seoul. As such, the design and plan was focused on the best measures to make known Korean culture through a design that sets itself apart from the landscape of Uzbekistan. To date, Korean parks or Seoul parks that have been built overseas have focused on the re-enactment of gardens and parks during the Josun Dynasty era. But with the Tashkent Park, the process of the 170,000 people from Goryeo was also reflected onto the design so that the culture and sensibilities of old Goryeo could be felt as well. Korean traditional garden design elements for the representation of the Korean identity are taken from the pilot study. This design element includes not only that of Goryeo, but also the Josun Dynasty era to allow local people to experience a general Korean traditional garden. The traditional beauty and lyricism of Korea was presented to Central Asia through the park in Tashkent so that the citizens could feel the simple yet down-to-earth beauty of Korean aesthetics. As such, the spatial experience of story-telling in Seoul Park evolves from two points of view. First, it is a spatial experience from the perspective of the Goryeo period and of foreigners. It is a continuum of a landscape experience where one can trace the sentiments of Korea and a hometown in Korea by passing through lyrical and multi-faceted spatial structures. Second, it is an experience that evolves from the viewpoint of an outsider, including the Tashkent citizens. It allows visitors to read the various methods and attitudes in an unfamiliar landscape and terrain. Through a story-telling that is reminiscent of the Silk Road through which trade with East Asia took place, visitors can interact with Korean culture in the Korean Garden and throughout the process they can feel the very Korean sentiments. This park presents the latest example of a 'Korean Garden' formed overseas and thus presents a clue to understanding the representation pattern of the Korean aspects of Korean Gardens through a study on the design strategies.

Digital painting: Image transfonnation, simulation, heterologie and transfonnation (현대회화에서의 형태와 물질 -Digital Transfiguration에 관한 연구-)

  • Jeong, Suk-Yeong
    • Journal of Science of Art and Design
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    • v.10
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    • pp.161-181
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    • 2006
  • The words which appeared in my theoretical study and work are image transformation to digital painting, simulation, heterologie and transfiguration, etc. Firstly, let's look into 'digital era' or 'new media era'. Nowadays, the image world including painting within the rapid social and cultural change, which is called as digital era, is having the dramatic change. Together with the development of scientific technology, large number of events which was deemed to be impossible is happening as real in image world Moreover, these changes in image world is greatly influencing to our life. The word which compresses this change of image world and shows is 'digital'. Digit, which means fingers in Latin, indicates separately changing signal, and to be more narrow, it indicates the continual signal of '0' and ' 1' in computer. The opposite word is 'analogue'. As analogue is the word meaning 'infer' or 'similarity', it indicates the signal or form which continuously changes along the series of time when it is compared to digital. Instead of analogue, digital is embossed as a major ruler along the whole area of our current culture. In whole culture and art area, and in whole generalscience, digital is appearing as it has the modernism and importance. The prefix, 'digital', e.g. digital media, digital culture, digital design, digital philosophy, etc, is treated as the synonym of modernism and something new. This advent of digital results the innovative change to the image world, creates the new beauty experience which we could not experience before, and forecasts the formation of advanced art and expansion of creative area. Various intellectual activities using computer is developing the whole world with making the infrastructure. Computer in painting work immediately accomplishes the idea of painters, takes part in simulation work, contingency such as abrupt reversal, extraction, twisting, shaking, obscureness, overlapping, etc, and timing to stimulate the creativity of painters, and provides digital formative language which enables new visual experience to the audience. When the change of digital era, the image appeared in my work is shown in 'transfiguration' like drawing. The word, 'transfiguration' does not indicate the completed and fixed real substance but indicate endlessly moving and floating shape. Thus, this concept is opposite to the substantial consideration, so that various concepts which is able to replace this in accordance with the similar cases are also exist such as change, deterioration, mutation, deformity of appearance and morphing which is frequently used in computer as a technical word. These concepts are not clearly classified, and variably and complicatedly related. Transfiguration basically means the denial of "objectivity' and '(continual) stagnation' or deviation from those. This phenomenon is appeared through the all art schools of art ever since the realism is denied in the 19th century. It is called as 'deformation' in case of expressionism, futurism, cubism, etc, in the beginning of the century, which its former indication is mostly preserved within the process of structural deviation and which has the realistic limit which should be preserved. On the contrary, dramatic transfiguration which has been showing in the modern era through surrealism is different in the point that dramatic transfiguration tends to show the deterioration and deviation rather than the preservation of indicated object. From this point, transfiguration coming out from morphing using computer deteriorates and hides the reality and furthermore, it replaces the 'reality'. Moreover, transfiguration is closely approached to the world of fake or 'imaginary' simulation world of Baudrillard. According to Baudrillard, the image hides and deteriorates the reality, and furthermore, expresses 'not existing' to 'imaginary' under the name of transfiguration. Certain reality, that is, image which is absent from the reality is created and overflowed, so that it finally replaces the reality. This is simulation as it is said by Baudrillard. In turn, Georges Bataille discusses about the image which is produced by digital technology in terms of heterologie. Image of heterologie is the visual signal which is established with the media. Image of media is to have the continuous characteristics of produce, extinction, and transformation, and its clear boundary between images becomes meaningless. The meaning of composition, excess, violation, etc of digital image is explained to heterological study or heteologie suggested as important meaning of Georges Bataille who is a heretic philosopher. As the form and image of mutation shows the shape in accordance with mechanical production, heterologie is introduced as very low materialism (or bas materialisme), in this theory. Heterologie as low materialism which is gradually changing is developing as a different concept and analysis because of the change of time in the late 20s century beside high or low meaning. Including my image, all images non-standardizes and transforms the code. However, reappearance and non-standardization of this code does not seem to be simple. The problem of transformation caused by transfiguration which appears in my digital drawing painting, simulation, heterologie, etc, are the continual problems. Moreover, the subject such as existence of human being, distance from the real life, politics and social problems are being extended to actual research and various expressing work. Especially, individual image world is established by digital painting transfiguration technique, and its change and review start to have the durability. The consciousness of observers who look at the image is changing the subject. Together with theoretical research, researchers are to establish the first step to approach to various image change of digital era painting through transfiguration technique using our realistic and historical image.

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