• Journal of Ocean Engineering and Technology
• /
• v.32 no.2
• /
• pp.95-105
• /
• 2018

An FLNG (floating liquefied natural gas) or LNG FPSO (floating production, storage and offloading) unit is a notable offshore unit with the increasing demand for LNG. The liquefaction process on an FLNG unit is the most important process because it determines the economic feasibility, but would be a hazard source because of the large quantity of hydrocarbons. While a high efficiency process such as C3MR has been preferred for onshore liquefaction processes, a relatively simple process such as the SMR (single mixed refrigerant) or DMR (dual mixed refrigerant) liquefaction process has been selected for offshore units because they require a more compact size, lighter weight, and higher safety due to their space limitation for facilities and long distance from shore. It is known that an SMR has the advantages of a simple configuration, small footprint, and lower risk. However, with an increased production rate, the inherent safety of SMR needs to be evaluated because of its small train capacity. In this study, the potential explosion risks of the SMR and DMR liquefaction processes were evaluated at the conceptual design stage. The results showed that an SMR has a lower overpressure than a DMR at the same frequency, only with a small production capacity of 0.9 MTPA. With increased capacity, the overpressure of the SMR was higher than that of the DMR. The increased number of trains increased the frequency in spite of the small amount of equipment per train. This showed that the inherent risk of an SMR is not always lower than that of a DMR, and an additional risk management strategy is recommended when an SMR is selected as the concept for an FLNG liquefaction process compared to the DMR liquefaction process.

• Clinics in Shoulder and Elbow
• /
• v.11 no.2
• /
• pp.77-81
• /
• 2008

The goal of rotator cuff repairs is to achieve high initial fixation strength, minimize gap formation, maintain mechanical stability under cyclic loading and optimize the biology of the tendon-bone interface until the cuff heals biologically to the bone. Single row repairs are least successful in restoring the footprint of the rotator cuff and are most susceptible to gap formation. Double row repairs have an improved load to failure and minimal gap formation. Transosseous equivalent repairs (suture bridge technique) have the highest ultimate load and resistance to shear and rotational forces and the lowest gap formation. Even though the superior advantages of double row and transosseous equivalent repairs, those techniques take longer surgical time and are more expensive than single row repairs. Therefore single row repairs can be useful in bursal side partial thickness or small size full thickess rotator cuff tear.

• Clinics in Shoulder and Elbow
• /
• v.11 no.2
• /
• pp.82-89
• /
• 2008

Ideal rotator cuff repair is to maintain high fixation strength and minimize gap formation for optimizing the environment of biologic healing of tendon to bone. Among the current repair techniques, the suture bridge technique is superior to single- or double-row repair in ultimate load to failure, gap formation, restoring anatomical footprint and achieving pressurized contact area. The suture bridge technique also minimizes gap formation and has rotational and torsional resistances allowing early rehabilitation. However, despite superior biomechanical characteristics of the suture bridge technique, there is no evidence that these mechanical advantages result in better clinical outcomes. Furthermore, there is no difference in failure rates between the double-row repair and suture bridge techniques. An appropriate repair technique should be determined based on tear size and pattern and tendon quality.

• Clinics in Shoulder and Elbow
• /
• v.20 no.4
• /
• pp.183-188
• /
• 2017

Background: To evaluate the clinical outcomes and associated repair integrity in patients treated with arthroscopic repair for a transtendinous rotator cuff tear followed by resection of the remnant rotator cuff tendon. Methods: Between July 2007 and July 2011, we retrospectively reviewed patients who were treated for transtendinous full-thickness tears in the tendinous portion of the rotator cuff by arthroscopic repair. Clinical outcomes were evaluated using the American Shoulder and Elbow Surgeons (ASES) score, the Shoulder Rating Scale of the University of California at Los Angeles (UCLA), the Constant-Murley score, a visual analogue scale (VAS) pain score, and range of motion (ROM). The repair integrity was determined by magnetic resonance imaging or ultrasonography. Results: There were 19 shoulders with transtendinous full-thickness tears in the tendinous portion of the rotator cuff. The ASES, UCLA, Constant-Murley, and VAS pain scores showed significant improvements in function and symptoms (all p<0.001). The active ROM for forward flexion and abduction was also significantly improved (p=0.002 and p<0.001, respectively). The postoperative radiological examination showed cuff integrity without a re-tear in 68.4% of patients. However, the UCLA, ASES, and Constant-Murley scores were not significantly different between healed and re-torn group (p=0.530, p=0.885, and p=0.262, respectively). Conclusions: Although repair of transtendinous rotator cuff tears followed by resection of the remnant rotator cuff tendon in the footprint has a relatively high re-tear rate, no significant difference was observed in the short-term clinical results between the re-tear and healed groups.

• Korean Journal of Remote Sensing
• /
• v.28 no.3
• /
• pp.307-318
• /
• 2012

To understand forest structures, the Geoscience Laser Altimeter System (GLAS) instrument have been employed to measure and monitor forest canopy with feasibility of acquiring three dimensional canopy structure information. This study tried to examine the potential of GLAS dataset in measuring forest canopy structures, particularly maximum canopy height estimation. To estimate maximum canopy height using feasible GLAS dataset, we simply used difference between signal start and ground peak derived from Gaussian decomposition method. After estimation procedure, maximum canopy height was derived from airborne Light Detection and Ranging (LiDAR) data and it was applied to evaluate the accuracy of that of GLAS estimation. In addition, several influences, such as topographical and biophysical factors, were analyzed and discussed to explain error sources of direct maximum canopy height estimation using GLAS data. In the result of estimation using direct method, a root mean square error (RMSE) was estimated at 8.15 m. The estimation tended to be overestimated when comparing to derivations of airborne LiDAR. According to the result of error occurrences analysis, we need to consider these error sources, particularly terrain slope within GLAS footprint, and to apply statistical regression approach based on various parameters from a Gaussian decomposition for accurate and reliable maximum canopy height estimation.

• Journal of Wetlands Research
• /
• v.14 no.3
• /
• pp.413-418
• /
• 2012

In this study, both habitat use analysis by rumen contents of Eurasian river otter (Lutra lutra) were carried out to investigate the preference of habitat environment and diet using their fecal samples. As the target sites, two streams (the Naechon-cheon and the Koonup-cheon) were selected in the upstream of the Hongcheon river, Hongcheon County, Gangwon Province. A total of 478 track samples (e.g., feces, scent and footprint) were found during the survey periods (May to November, 2009 and November, 2010). The dominant points, where the tracks of river otters were observed, were areas with the low depth(0.5-1m) and the slow flow velocity (5m/sec). Also, both rocks and rock-beds were preferred but artificial facilities were avoided. This ecological study of river otters using habitat use analysis and diet analysis by rumen contents will be useful fundamental information to conserve the river otter populations, and to protect their habitats.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.10 no.3
• /
• pp.176- 184
• /
• 2010

A low-power inductorless 1:4 DEMUX and a 4:1 MUX for a 90 nm CMOS are presented. The DEMUX can be operated at a speed of 25 Gb/s with the power supply voltage of 1.05 V, and the power consumption is 8.9 mW. The area of the DEMUX core is $29\;{\times}\;40\;{\mu}m^2$. The operation speed of the 4:1 MUX is 13 Gb/s at a power supply voltage of 1.2 V, and the power consumption is 4 mW. The area of the MUX core is $30\;{\times}\;18\;{\mu}m^2$. The MUX/DEMUX mainly consists of differential pseudo-NMOS. In these MUX/DEMUX circuits, logic swing is nearly rail-to-rail, and a low $V_{dd}$. The component circuit is more scalable than a CML circuit, which is commonly used in a high-performance MUX/DEMUX. These MUX/DEMUX circuits are compatible with conventional CMOS logic circuit, and it can be directly connected to CMOS logic gates without logic level conversion. Furthermore, the circuits are useful for core-to-core interconnection in the system LSI or chip-to-chip communication within a multi-chip module, because of its low power, small footprint, and reasonable operation speed.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• autumn
• /
• pp.99-103
• /
• 2003

The most commonly used method for space management in the industry is development of site plans. These plans outline how to manage material deliveries, staging areas, and crane locations for construction sites in suburban area but not in congested urban areas. This study focuses on how to efficiently manage space for construction facilities on high-rise buildings in congested urban areas where normally space for facilities around a building footprint is not available. The limitations of available horizontal space create a need to explore vertical expansion of facilities. This raises new aspects of vertical facility handling and flow that need to be considered in the facility design problem. The construction facilities layout plan method provides layout planners with a valuable technique to develop efficient sequences of work that optimally defines how to efficiently utilize the construction facilities and minimize the travel of specific facilities effort on multiple-floor buildings. A genetic algorithm-based heuristic will be presented for generating block layouts for multiple-floor la)rout problems.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.41 no.5
• /
• pp.783-795
• /
• 2017

This study measured consumer's recognition, reliability, emotion and images about current eco-marks as well proposed an eco-mark rating scale and mark designs to improve consumer's trust on the fashion product marks. We used a questionnaire survey to collect data from 150 persons about knowledge, interests, and practice on eco fashion products in relation to trustfulness and positive images for three domestic and three international eco-marks. We evaluated and gave eco scores to six fiber-type products (cotton, organic cotton, wool, polyester, biodegradable polyester and nylon) in terms of consumer's use, water & land consumption, waste amount, carbon footprint, and toxicity. We suggested a new 5-level rating scale for eco marks, which quantified the concept of environmental friendliness of fiber products. The design for eco-mark of rating scale showed the total grade with two sub scores of environmental sides and human sides developed with an improved visual understanding for consumers. The design is one through benchmarking the energy-consumption efficiency mark, which is familiar to consumers such as a half circle shape to save environment resources to alarm consumers to environment problems.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.3
• /
• pp.578-585
• /
• 2009

In this paper, we present the design of an electromagnetic scanning mirror with torsional springs. The scanning mirror consisting of torsional springs and electromagnetic coils was designed for the applications of laser animation systems. We analyzed and optimized three types of torsional springs, namely, straight beam springs (SBS), classic serpentine springs (CSS), and rotated serpentine springs (RSS). The torsional springs were analyzed in terms of electrical resistance, fabrication error tolerance, and resonance mode separation of each type using analytical formula or numerical analysis. The RSS has advantages over the others as follows: 1) A low resistance of conductors, 2) wide resonance mode separation, 3) strong fabrication error tolerance, 4) a small footprint. The double-layer coils were chosen instead of single-layer coils with respect to electromagnetic forces. It resulted in lower power consumption. The geometry of the scanning mirror was optimized by calculations; RSS turn was 12 and the width of double-layer coil was $100{\mu}m$, respectively. When the static rotational angle is 5 degrees, the power consumption of the mirror plate was calculated to be 9.35 mW since the resistance of the coil part and a current is $122{\Omega}$ and 8.75 mA, respectively. The power consumption of full device including the mirror plate and torsional springs was calculated to be 9.63 mW.