• Investigative Magnetic Resonance Imaging
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• v.5 no.2
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• pp.123-129
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• 2001

Purpose: The purposes of this study are to evaluate normal MR spectroscopy (MRS) data of the cerebellum and pons, and to evaluate intra-unit and inter-unit differences of the results. Materials and methods: Nine normal volunteers (mean age 23 years) were studied with two 1.5 Tesla MR units (A and B units). A total of four sessions of MRS study were performed with two sessions in ea.ch MR unit in each volunteer. In each session, MRS data were obtained from bilateral cerebellar hemisphere and pons. MRS was performed using spin-echo single voxel technique with repetition time of 2000 ms, echo time of 288ms and 128 averagings. Voxel size was $2{\;}{\times}{\;}2{\;}{\times}{\;}1.5{\;}cm$ in the cerebellum and $1.5{\;}{\times}{\;}1.5{\;}{\times}{\;}1.5{\;}cm$ in the pons. Metabolite ratios of NAA/Cho, NAAcCr, NAAc(Cho+Cr) and Cr/Cho (both peak heights and the peak areas) were compared among the results of four sessions of MRS for evaluation of intra-unit and inter-unit differences. Results: In the cerebellum, mean (SO values of peak height NAA/Cho, NAA/Cr, NAA/(Cho+Cr) and Cr/Cho ratios obtained in the first session of A unit were $1.08{\pm}O.16,{\;}1.44{\pm}O.286,{\;}0.61{\pm}O.09{\;}and{\;}O.76{\pm}0.13$, respectively. Comparing with the results of the second session, intra-unit differences were 3-7%. In B unit intra-unit differences were 1-9%, except for 22% of Cr/Cho ratio. Inter-unit differences between A and B units were 1-26%. In the pons, mean ISD values of peak height NANCho, NANCr, NANICho + Cr) and Cr/Cho ratios obtained in the first session of A unit were $1.51{\pm}O.35,{\;}3.35{\pm}O.78,{\;}1.02{\pm}0.16{\;}and{\;}0.47{\pm}O.14$, respectively. Mean NAAfCho, NANCr and NAAI(Cho+ Cr} ratios of the pons were significantly higher than those of the cerebellum. Intra-unit differences were 2-21 % in A unit and 4-18 % in B unit. Inter-unit differences between A and B units were 1-18%. The mean values obtained by using peak area were generally higher and wider in range than those of peak height in both units. Conclusion: Mean NAAfCho, NAAlCr and NAAf(Cho+Cr) ratios of the cerebellum were significanHy lower than those of the pons. Intra-unit differences of most metabolites ratios were generally not significant, whereas inter-unit differences were greater than intra-unit differences in more metabolite ratios. Therefore, normal MRS data of the cerebellum and the pons should be obtained in every MR unit, before MRS applications in the diseases of the cerebellum and the pons.

• Investigative Magnetic Resonance Imaging
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• v.12 no.2
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• pp.131-141
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• 2008

Purpose : To investigate the feasibility and accuracy of Proton Resonance Frequency (PRF) shift based magnetic resonance (MR) temperature mapping utilizing the self-developed center array-sequencing phase unwrapping (PU) method for non-invasive temperature monitoring. Materials and Methods : The computer simulation was done on the PU algorithm for performance evaluation before further application to MR thermometry. The MR experiments were conducted in two approaches namely PU experiment, and temperature mapping experiment based on the PU technique with all the image postprocessing implemented in MATLAB. A 1.5T MR scanner employing a knee coil with $T2^*$ GRE (Gradient Recalled Echo) pulse sequence were used throughout the experiments. Various subjects such as water phantom, orange, and agarose gel phantom were used for the assessment of the self-developed PU algorithm. The MR temperature mapping experiment was initially attempted on the agarose gel phantom only with the application of a custom-made thermoregulating water pump as the heating source. Heat was generated to the phantom via hot water circulation whilst temperature variation was observed with T-type thermocouple. The PU program was implemented on the reconstructed wrapped phase images prior to map the temperature distribution of subjects. As the temperature change is directly proportional to the phase difference map, the absolute temperature could be estimated from the summation of the computed temperature difference with the measured ambient temperature of subjects. Results : The PU technique successfully recovered and removed the phase wrapping artifacts on MR phase images with various subjects by producing a smooth and continuous phase map thus producing a more reliable temperature map. Conclusion : This work presented a rapid, and robust self-developed center array-sequencing PU algorithm feasible for the application of MR temperature mapping according to the PRF phase shift property.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.103-109
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• 2016

Polyethylene pipes has useful benefits which are anti-corrosive and flexible material, so it is used to gas pipes but also class 3 water pipes of nuclear power plant, process pipes of petrochemical plant and chemical plant. So the usage of polyethylene pipes is widely increased. But it has been limited for the usage of polyethylene, because it can not be directly detected to fusion joints by using non destructive evaluation. Polyethylene pipes are connected by two methods, one is butt fusion and the other is electrofusion. Butt fusion is widely used to connecting the pipes. It is proposed to method for determining the reliability of joints in this study that is detection of the melt flow zone at fusion joints. In this study, middle density polyethylene is used, outside diameter of the test specimen is 225mm and thickness is 20.5mm. Speed of ultrasonic of this test specimen is 2,200m/s. Test specimens were fabricated by varying the heating time which means from 0% to 130% applying time through heating plate to polyethylene for detecting melt flow zone. Also 4 additional test specimens were made, one was made that not scrapping attached surface of pipes but applying 100% of the proper heating time and the others were made to include of soil, gravel and vinly tape paper at fusion joints, that were also applied 100% of proper heating time. Ultrasonic testing to measure the melt flow zone of 20 test specimens was conducted by using 3.5MHz and 5.0MHz ultrasonic probes and melt flow zone measuring was conducted to three times at different point to one specimen. To differentiate the melt flow zone signal, post image processing was equally conducted to all test results and image levels, contrast, sharpen, threshold were adopted to all teat results and the test results were displayed gray scale. From the results, for the shorter heating times the reflection area of multiple echo have been increased, so the data was obtained from the position where it can be eliminated as much as possible. At 80% of proper heating time(168 sec.), the signal of melt flow zone was obtained clearly, so measuring could be conducted. From 7% of proper heating time(15 sec.) to shorter heating times. we could not obtain the signal because test specimen was not fused. From the result, we can verify that measuring of melt flow zone by using phased array ultrasonic imaging method is possible. And we can verify to complete and incomplete butt fusion by measuring the melt flow zone.

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.401-407
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• 2011

The purpose of this study is to know the differences of MR spectra, obtained from normal volunteers by variable TE value, through the quantitative analysis of brain metabolites by peak integral and SNR between 1.5T and 3.0T, together with PRESS and STEAM pulse sequence. Single-voxel MR proton spectra of the human brain obtained from normal volunteers at both 3.0T MR system (Magnetom Trio, SIEMENS, Germany) and 1.5T MR system (Signa Twinspeed, GE, USA) using the STEAM and PRESS pulse sequence. 10 healthy volunteers (3.0T:3 males, 2 females; 1.5T : 3 males, 2 females) with the range from 22 to 30 years old (mean 26 years) participated in our study. They had no personal or familial history of neurological diseases and had a normal neurological examination. Data acquisition parameters were closely matched between the two field strengths. Spectra were recorded in the white matter of the occipital lobe. Spectra were compared in terms of resolution and signal-to-noise ratio(SNR), and echo time(TE) were estimated at both field strengths. Imaging parameters was used for acquisition of the proton spectrum were as follow : TR 2000msec, TE 30ms, 40ms, 50ms, 60ms, 90ms, 144ms, 288ms, NA=96, VOI=$20{\times}20{\times}20mm3$. As the echo times were increased, the spectra obtained from 3.0T and 1.5T show decreased peak integral and SNR at both pulse sequence. PRESS pulse sequence shows higher SNR and signal intensity than those of STEAM. Especially, Spectra in normal volunteers at 3.0T demonstrated significantly improved overall SNR and spectral resolution compared to 1.5T(Fig1). The spectra acquired at short echo time, 3T MR system shows a twice improvement in SNR compared to 1.5T MR system(Table. 1). But, there was no significant difference between 3.0Tand 1.5T at long TE It is concluded that PRESS and short TE is useful for quantification of the brain metabolites at 3.0T MRS, our standardized protocol for quantification of the brain metabolites at 3.0T MRS is useful to evaluate the brain diseases by monitoring the systematic changes of biochemical metabolites concentration in vivo.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.387-394
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• 2012

The study was conducted to develop an effective forest resources use models for an alternate use of abandoned quarry by an attitude survey. According to the result of survey, a pessimistic view due to dust, noise pollution, and forest damage was 5% higher than an affirmative view by economic benefits from the development of quarry. The 42% of the respondents preferred the alternate use of abandoned quarry and the 25% of the respondents wanted an art and cultural space. The optimum size of alternate use was 5-10 ha (43%) with the requirement of nearby residents (32%). According to the SWOT analysis for abandoned quarry, the strength factors were an effective use of land, the content development of modern industrial inheritance + cultural and art fusion, attraction for nearby city and visitors, a harmony of beauty landscape and clean environment, and a sustainable increase of domestic and foreign visitors with the 5-day-work week. The opportunity factors were the improvement of traffic networks through KTX and local highway, the creation of the new growth engines with the establishment of artistic creation belts, the providing of unique cultural and art space through grafting of tour and education, the creation of local income through stone processed goods, and the vitalization of local development through eco-city. The weakness factors were a psychological remoteness and backwardness, and the weakness of staying tour infra. The threat factors were a poor financial support for sustainable development in nearby quarry and a modify of legal and institutional system for the alternated use of abandoned quarry. The developed restoration models for the alternate use in abandoned quarry are classified to a sculpture park, a waterfall and lake park, a rock-climbing, a sports park + forest park, a native botanical garden, a culture and art park, a complex park, a water storage site, a water storage site to extinguish forest fire, a geriatric hospital, an agricultural facility, and a school site types etc. The results suggest that the alternate use in the abandoned soil and stone quarry is needed to establish facility use models with consideration of user's preference.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.4
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• pp.113-120
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• 2006

Wastewater generated through the food waste recycling process have known high concentration, BOD 20,000~150,000 mg/L, which has to treat to the proper level because of a ban on reclamation. But it is impossible to treat less than 10 days by existing water treatment plant. Ecodays Ltd. is to treat this wastewater during 2~4 days by ER-1, which can simultaneously induce the modified PFR(Plug Flow Reactor) of the oxygen transfer rate, MLVSS concentration, and influent concentration to top from bottom of reactor. We tested the pilot test about low concentration food wastewater(BOD 16,500 mg/L) and high concentration food wastewater(64,431 mg/L) at the food waste recycling plant of H-Gun(20t/d). Hydraulic retention time(HRT) of ER-1 for low concentration food wastewater is 2.5day. In low concentration conditions, ER-1 treatment efficiency is to appear BOD 99%, COD 98%, TN 97%, and TP 96%. While ER-1 process for high concentration food wastewater treatment is composed 2 stages, which are to be HRT 2.5day for law wastewater and HRT 1.5 day for secondary treatment. In high concentration conditions, ER-1 treatment efficiency is to appear BOD 97%, COD 84%, TN 66%, and TP 95%. It is treated without temperature control about high temperature($50^{\circ}C$) to appear low treatment efficiency in high concentration conditions.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.13-22
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• 2012

This study was conducted to establish ecotourism as an introduction to sustainability and international cooperation. As a plan to retain the original meaning of ecotourism, the introduction of a program to certify/designateecotourism is being vitalized in many countries around the world. In Korea as well, an agenda to the introduction of an "Ecotourism Designation System,"which aims to ensure the quality of ecotourism at a certain level, was submitted by the Ministry of Environment to the National Assembly in June 2011, and the promotion for a demonstration program is planned this year to introduce the system. Japan has been carrying out the certification systems Good Eco-tour, which certifies the sustainability of ecotourism providers and accommodations since 2006, respectively, and has been securing the sustainability of ecotourism by enactment in 2008, as the world's first law to promote ecotourism. And the second general conference of the first Global Partnership for Sustainable Tourism(GPST) was held in Korea in March 2012, particularly, there was an agreement that the promotion of Asia and the Pacific Area Network for sustainable tourism would center around Korea, and accordingly, it is expected that Korea's status as a core country for ecotourism in the Asia-Pacific Area will increase. While the demand for an approach to natural resources is rapidly increasing, we should be active in providing an institutional strategy such as a designation system to secure the sustainability of ecotourism and seeking a plan for cooperation and network vitalization in the Asia-Pacific Area where similar natural resources and cultures are shared.

• Progress in Medical Physics
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• v.24 no.1
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• pp.25-34
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• 2013

To investigate effects of phase mask on susceptibility-weighted images (SWI) using voxel-based analyses in normal elderly subjects. A three-dimensional (3D) gradient echo sequence ran to obtain SWIs in 20 healthy elderly subjects. SWIs with two (SWI2) and four (SWI4) phase multiplications were achieved with positive (PSWI) and negative (NSWI) phase masks to investigate phase mask effects. The voxel-based comparisons were performed using paired t-tests between PSWI and NSWI and between SWI2 and SWI4. Differences of signal intensities between magnitude images and SWI4 were larger than those between magnitude images and SWI2s. Differences of signal intensities between magnitude images and PSWIs were larger than those between magnitude images and NSWIs. Moreover, the signal intensities from NSWI2s and NSWI4s were greater than those from PSWI2s and PSWI4s, respectively. More differences of signal intensities between NSWI4 and PSWI4s were found than those between NSWI2s and PSWI2s in the whole brain images. The voxel-based analyses of SWI could be beneficial to investigate susceptibility differences on the entire brain areas. The phase masking method could be chosen to enhance brain tissue contrast rather than to enhance venous blood vessels. Therefore, it is recommended to apply voxel-based analyses of SWI to investigate clinical applications.

• Investigative Magnetic Resonance Imaging
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• v.17 no.4
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• pp.294-307
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• 2013

Purpose : To investigate the correlations between Seoul Neuropsychological Screening Battery (SNSB) scores and the gray matter volumes (GMV) in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI) and cognitively normal (CN) elderly subjects with correcting the genotypes. Materials and Methods: Total 75 subjects were enrolled with 25 subjects for each group. The apolipoprotein E (APOE) epsilon genotypes, SNSB scores, and the 3D T1-weighted images were obtained from all subjects. Correlations between SNSB scores and GMV were investigated with the multiple regression method for each subject group using both voxel-based and region-of-interest-based analyses with covariates of age, gender, and the genotype. Results: In the AD group, Rey Complex Figure Test (RCFT) delayed recall scores were positively correlated with GMV. In the MCI group, Seoul Verbal Learning Test (SVLT) scores were positively correlated with GMV. In the CN group, GMV negatively correlated with Boston Naming Test (K-BNT) scores and Mini-Mental State Examimation (K-MMSE) scores, but positively correlated with RCFT scores. Conclusion: When we used covariates of age, gender, and the genotype, we found statistically significant correlations between some SNSB scores and GMV at some brain regions. It may be necessary to further investigate a longitudinal study to understand the correlation.

• Clinical and Experimental Pediatrics
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• v.46 no.10
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• pp.966-971
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• 2003

Purpose : It is now well established that infection and inflammation play an important role in the pathogenesis of ischemic brain damage. The loss of neutrophils from systemic circulation is an associated finding in injury mediated by granulocyte. Periventricular leukomalacia(PVL) caused by ischemia is the principal form of brain injury in premature infants. This study was conducted to evaluate whether the low neutrophil count is associated with periventricular leukomalacia(PVL) in premature infants. Methods : Retrospective review of medical records was undertaken. Subjects were premature infants with a birth weight of less than 1,500 gm, admitted to the Neonatal Intensive Care Unit of Kyungpook University Hospital. A complete blood count of peripheral blood was done within the 1st hour of life. Neutropenia was defined as absolute neutrophil count < $1,500/mm^3$, PVL as increased periventricular echodensities followed by cyst formation on ultrasonography or corresponding signs on brain MRI. Results : Thirteen infants out of a total population of 37 revealed neutropenia. Respiratory distress syndrome and requirement for respiratory support were not different between infants with neutropenia( neutropenia group) and infants without neutropenia(control group). Intraventricular hemorrhage (IVH) and grade 3 and 4 IVH were more frequent in neutropenia group(P<0.05). There was no statistically significant increase of PVL in neutropenia group. The neutrophil count was $18,760.0{\pm}10,266.1/mm^3$, $7,272.0{\pm}7,435.0/mm^3$ infants with PVL and $11,131.7{\pm}3,386.5/mm^3$, $2,407.5{\pm}1,933.1/mm^3$ in infants without PVL, respectively. The frequency of mechanical ventilation and artificial surfactant therapy was higher in infants with PVL compared with infants without PVL, but statistical analysis was not performed due to small number of subjects. Conclusion : A low number of neutrophils in the systemic circulation was not associated with an increased risk of PVL in premature infants.