• Tunnel and Underground Space
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• v.17 no.3 s.68
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• pp.216-224
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• 2007

Blasting, using shock and dynamic energy of explosive, is very effective tunnel excavation method. But it had serious problem which is the blast vibration and over-break. In recent study, pre-cracked excavation method using notch hole reduced blast vibration and over-break in tunnel, so we performed study about developing notch bit system for making notch hole. In order to make notch hole effectively we had perform drilling experiments changing length and height of notch and in order to improve speed and precision of drilling we had developed notch bit system which consists of drilling bit, notch bit, adapter and notch guide.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.1608-1609
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• 2011

국토해양부에서는 건설사업의 생산성을 향상시키고 건설사업의 효율성을 제고하기 위해 건설기술관리법 제15조의 2에 따라 건설공사지원통합정보체계의 구성.운영에 관한 법률을 마련하고 1998년부터 건설사업정보화(Continuous Acquisition Life-Cycle Support : CALS)를 추진중에 있다. 건설사업정보화의 일환으로 건설공사비의 상당부분을 차지하고 개인의 소유권과 관계되어 있어 민원 소지가 많은 보상자료를 관리하기 위해 용지보상시스템이 기 개발되어 운영중에 있으나 보상비 지출의 핵심과정인 지급단계가 국가재정정보시스템과 별도로 운영중에 있어 체계적인 보상자료 관리 및 보상비 지급의 이력관리가 제대로 이루어지 지고 있지 않다. 이는 곧 부적절한 보상비 집행으로 인한 국고예산 낭비의 소지가 있고 보상비 집행에 대한 대민 신뢰도 저하로 인해 다수의 소송으로 이어질수 있다. 이에 기존의 보상비 집행업무 프로세스 개선 및 건설CALS 용지보상시스템과 디지털예산회계시스템의 연계를 통해 보상비 집행의 투명성을 확보하고 민원인들에게 대민행정에 대한 신뢰도를 높일 수 있는 방안을 제시하고자 한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.389-389
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• 2022

상수도 관망에서의 유량 측정은 유수율을 결정하는 데 있어서 중요한 평가 수단이다. 따라서, 유량 측정을 위해 유량계를 활용하는데, 높은 빈도의 자료를 획득할 수 있는 수압계는 시중에서 저가로 활용 가능하지만, 상수도관망 예산의 상당부분을 차지하고 있는 유량계는 수압계보다 고가에도 낮은 빈도의 자료만을 획득하는 비용 대비 낮은 효율을 가진다. 만약 수압계의 측정자료를 유량자료로 고속전환하는 기술을 개발하면 기존의 유량계보다 적은 비용으로 고빈도의 유량자료를 획득할 수 있다. 상수도 관망에서 수압자료를 유량 자료로 전환하는 기술은 기존 관망에서 유도된 지배방정식에서 임의 관망에서 일련의 유도과정을 거쳐 상하류 단사이 수압과 유량의 관계를 형성하고, 이러한 관계를 활용하여 간단한 저수조-관망-밸브 체제에서 관망 내의 특정지점에서의 시간상 수압자료와 시간상 유량자료의 비를 정의한 다음, 임의의 지점에서 측정된 수압자료를 정의한 비로 나타나는 임피던스 역수를 역푸리에 전환하면 시간상의 유량자료를 획득할 수 있는 원리이다. 이러한 수압-유량 전환기술의 원리를 가지고 개발된 기술의 정확도를 확인하는 과정을 수행하였으며, 이는 전통적 천이류 해석 방법인 특성선 모델로 비교하는 수치해석적인 방법 그리고 실제 설치된 관망을 사용해서 수압을 측정하고, 지정된 지점에서 유량을 정밀측정하여 비교하는 실험적인 방법을 통해 정확도를 비교해봄으로써 개발된 기술을 검증해보고자 한다.

• The Korean Journal of Air & Space Law and Policy
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• v.32 no.1
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• pp.201-224
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• 2017

The main subject of this article focused on the legal status of the military aircraft in the high seas. For this the legal status of the military aircraft, the freedom of overflight, the right of hot pursuit, the right of visit and Air Defense Identification Zone (ADIZ) were dealt. The 1944 Chicago Convention neither explicitly nor implicitly negated the customary norms affecting the legal status of military aircraft as initially codified within the 1919 Paris Convention. So the status of military aircraft was not redefined with the Chicago Convention and remains, as stated in the 1919 Paris Convention, as a norm of customary international law. The analyses on the legal status of the military aircraft in the high seas are found as follows; According to the Article 95 of the 1982 United Nations Convention on the Law of the Sea (UNCLOS) warships on the high seas have complete immunity from the jurisdiction of any State other than the flag State. We can suppose that the military aircraft in the high seas have also complete immunity from the jurisdiction of any State other than the flag State. According to the Article 111 (5) of the UNCLOS the right of hot pursuit may be exercised only by warships or military aircraft, or other ships or aircraft clearly marked and identifiable as being on government service and authorized to that effect. We can conclude that the right of hot pursuit may be exercised by military aircraft. According to the Article 110 of the UNCLOS a warship which encounters on the high seas a foreign ship, is not justified in boarding it unless there is reasonable ground for suspecting that: (a) the ship is engaged in piracy, (b) the ship is engaged in the slave trade, (c) the ship is engaged in an unauthorized broadcasting and the flag State of the warship has jurisdiction under article 109, (d) the ship is without nationality, or (e) though flying a foreign flag or refusing to show its flag, the ship is, in reality, of the same nationality as the warship. These provisions apply mutatis mutandis to military aircraft. As for Air Defence Identification Zone (ADIZ) it is established and declared unilaterally by the air force of a state for the national security. However, there are no articles dealing with it in the 1944 Chicago Convention and there are no international standards to recognize or prohibit the establishment of ADIZs. ADIZ is not interpreted as the expansion of territorial airspace.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.8
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• pp.866-871
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• 2006

The nutrient recovery in phosphate crystallization process was investigated by using laboratory scale uptlow reactors, adopting sequencing batch type configuration. The industrial waste lime was used as potential cation source with magnesium salt($MgCl_2$) as control. The research was focused on its successful application in a novel integrated sludge treatment process, which is comprised of a high performance fermenter followed by a crystallization reactor. In the struvite precipitation test using synthetic wastewater first, which has the similar characteristics with the real fermentation effluent, the considerable nutrient removal(about 60%) in both ammonia and phosphate was observed within $0.5{\sim}1$ hr of retention time. The results also revealed that a minor amount(<5%) of ammonia stripping naturally occurred due to the alkaline(pH 9) characteristic in feed substrate. Stripping of $CO_2$ by air did not increase the struvite precipitation rate but it led to increased ammonia removal. In the second experiment using the fermentation effluent, the optimal dosage of magnesium salt for struvite precipitation was 0.86 g Mg $g^{-1}$ P, similar to the mass ratio of the struvite. The optimal dosage of waste lime was 0.3 g $L^{-1}$, resulting in 80% of $NH_4-N$ and 41% of $PO_4-P$ removal, at about 3 hrs of retention time. In the microscopic analysis, amorphous crystals were mainly observed in the settled solids with waste lime but prism-like crystals were observed with magnesium salt. Based on mass balance analysis for an integrated sludge treatment process(fermenter followed by crystallization reactor) for full-scale application(treatment capacity Q=158,880 $m^3\;d^{-1}$), nutrient recycle loading from the crystallization reactor effluent to the main liquid stream would be significantly reduced(0.13 g N and 0.19 g P per $m^3$ of wastewater, respectively). The results of the experiment reveal therefore that the reuse of waste lime, already an industrial waste, in a nutrient recovery system has various advantages such as higher economical benefits and sustainable treatment of the industrial waste.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.1
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• pp.11-36
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• 2021

The solar annual (Sa) and semiannual (Ssa) tides account for much of the non-uniform annual and seasonal variability observed in sea levels. These non-equilibrium tides depend on atmospheric variations, forced by changes in the Sun's distance and declination, as well as on hydrographic conditions. Here we employ tidal harmonic analyses to calculate Sa and Ssa harmonic constants for 21 Korean coastal tidal stations (TS), operated by the Korea Hydrographic and Oceanographic Agency. We used 19 year-long (1999 to 2017) 1 hr-interval sea level records from each site, and used two conventional harmonic analysis (HA) programs (Task2K and UTide). The stability of Sa harmonic constants was estimated with respect to starting date and record length of the data, and we examined the spatial distribution of the calculated Sa and Ssa harmonic constants. HA was performed on Incheon TS (ITS) records using 369-day subsets; the first start date was January 1, 1999, the subsequent data subset starting 24 hours later, and so on up until the final start date was December 27, 2017. Variations in the Sa constants produced by the two HA packages had similar magnitudes and start date sensitivity. Results from the two HA packages had a large difference in phase lag (about 78°) but relatively small amplitude (<1 cm) difference. The phase lag difference occurred in large part since Task2K excludes the perihelion astronomical variable. Sensitivity of the ITS Sa constants to data record length (i.e., 1, 2, 3, 5, 9, and 19 years) was also tested to determine the data length needed to yield stable Sa results. HA results revealed that 5 to 9 year sea level records could estimate Sa harmonic constants with relatively small error, while the best results are produced using 19 year-long records. As noted earlier, Sa amplitudes vary with regional hydrographic and atmospheric conditions. Sa amplitudes at the twenty one TS ranged from 15.0 to 18.6 cm, 10.7 to 17.5 cm, and 10.5 to 13.0 cm, along the west coast, south coast including Jejudo, and east coast including Ulleungdo, respectively. Except at Ulleungdo, it was found that the Ssa constituent contributes to produce asymmetric seasonal sea level variation and it delays (hastens) the highest (lowest) sea levels. Comparisons between monthly mean, air-pressure adjusted, and steric sea level variations revealed that year-to-year and asymmetric seasonal variations in sea levels were largely produced by steric sea level variation and inverted barometer effect.

• Journal of Korean Society of Steel Construction
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• v.15 no.1
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• pp.87-96
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• 2003

The Ssteel-Cconcrete (SC) Ccomposite Ccolumn is a new Ccomposite Ccolunin system, where hoops are welded between flanges of H-shapesd steel and concrete is filled in spaces between flanges are filled with con crete. Tests of SC composite columns were performed previously to determine their compression, bending and shear strength, and it showed good structural behavior. But sSince a column is usually subjected to an axial compression force, and bending it ihas needed to be bent forevaluate its structural behavior to be evaluated when its axial load and bending isaresimultaneously applied to the SC composite column. In this paper, tests were conducted to investigate the bending strength of SC composite columns subjected to axial compression force and bending moment. The parameters of the tests were concrete, a stud bolt, a hoop and a magnitude of axial compression. The test results showed that the maximum bending strength and ductility of an SC composite column were increased by 33-42% and 33-63%, respectively, comparinged to those of a bare steel column. Also, the results obtained bywith the Korean Limit State Design Code (LSD) presents a considerably safe side value compared to those of the Eurocode-4 and the Japan Code. However, wWhen the axial compression force is was increased, however, there awere considerable differences between the maximum strength obtained by the test and the LSD analysis. For this reason, it is recommended tothe use of the Eurocode-4 is recommended when calculates the strength of an SC composite column is being calculated, since the Eurocode-4 gives us a better estimation.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.8
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• pp.852-859
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• 2006

The novel microbial process such as Anammox(anaerobic ammonium oxidation) and Canon(completely autotrophic nitrogen removal over nitrite) processes is promising biotechnology to remove nitrogen from ammonium-rich wastewater like anaerobic sludge digester liquid. In this research, a new Canon-type nitrogen removal process adopting upflow granular sludge bed type configuration was investigated on its feasibility and process performance, using synthetic wastewater and sludge digester liquids. Air as an oxygen source was provided in an external aeration chamber with flow recirculation. In the first experiment using the synthetic wastewater(up to 110 mg $NH_4$-N $L^{-1}$), the ammonium removal was about 95%(92% for T-N) at effective hydraulic retention time(HRT) for 3.8 days. In the second experiment using the sludge digester liquids($438{\pm}26$ mg $NH_4$-N $L^{-1}$), the total nitrogen removal was $94{\pm}1.7%$ at HRT for 5.4 days and $76{\pm}1.5%$ at HRT for 3.8 days, respectively. Little nitrite and nitrate were observed in the effluent of both experiments. The process revealed quite a lower oxygen($0.29{\sim}0.59$ g $O_2$ $g^{-1}N$) and less alkalinity($3.1{\sim}3.4$ g $CaCO_3$ $g^{-1}N$) consumption as compared to other new technology in microbial nitrogen removal. The process also offers the economical compact reactor configuration with excellent biomass retention, resulting in lower cost for investment and maintenance.

• Journal of Korean Society of Steel Construction
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• v.26 no.5
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• pp.385-396
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• 2014

Traditionally, domestic steel design and construction practice has provided extra shear studs to moment frame beams even when they are designed as non-composite beams. In the 1994 Northridge earthquake, connection damage initiated from the beam bottom flange side was prevalent. The upward moving of the neutral axis due to the composite action between steel beam and floor deck was speculated to be one of the critical causes. In this study, full-scale seismic testing was conducted to investigate the side effects of the composite action in steel seismic moment frames. The specimen PN700-C, designed following the domestic connection and floor deck details, exhibited significant upward shift of the neutral axis under sagging (or positive) moment, thus producing high strain demand on the bottom flange, and showed a poor seismic performance because of brittle fracture of the beam bottom flange at 3% story drift. The specimen DB700-C, designed by using RBS connection and with the details of minimized floor composite action, exhibited superior seismic performance, without experiencing any fracture or concrete crushing, almost identical to the bare steel counterpart (specimen DB700-NC). The results of this study clearly indicate that the beams and connections in seismic steel moment frames should be constructed to minimize the composite action of a floor deck if possible.

• Korean Journal of Food Science and Technology
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• v.38 no.4
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• pp.543-547
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• 2006

In order to improve wine quality, the selection of yeast strain and of additives in the manufacture of Bokbunja (Rubus coreanus Miq.) wine was investigated. The chemical composition of the edible portions of Bokbunja fruits was 86.5% moisture, 0.2% crude protein, 0.9% crude fat, 6.6% crude fiber, 0.5% ash and $10^{\circ}Brix$ sugar, and was 2.99% fructose, 2.53% glucose and 0.07% sucrose in fruit extract. The predominant organic acids in the fruit were citric acid (14.57 mg/mL) and malic acid (2.24 mg/mL) with smaller amounts of shikimic, pyroglutamic and oxalic acid. During fermentation, citric and malic acid levels decreased, while formic and acetic acid were released. Saccharomyces cerevisiae KCCM 12224 (Sc-24) was more favorable for alcoholic fermentation of Bokbunja and the addition of 200 ppm of potassium metabisulphite to must was more efficient than other $SO_2$ sources with a higher overall acceptability score. Sc-24 increased alcohol production from 9.8 to 14.8% in a sugar concentration dependent manner $(18-28^{\circ}Brix)$. The color value of early stage Bokbunja must was improved by supplementing with Japanese apricot extract, but this did not influence the color value of Bokbunja wine after primary fermentation. The astringent taste of Bokbunja wine was reduced by removing the seed from the fruit. Sugar solution (50%, w/v) was used instead of sugar power to prevent the possibility of undissolved sugar due to insufficient mixing. This substitution did not influence sensory evaluation.