• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1859-1864
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• 2004

An effective methodology is reported for the optimal design of multisite batch production/transportation and storage networks under uncertain demand forecasting. We assume that any given storage unit can store one material type which can be purchased from suppliers, internally produced, internally consumed, transported to or from other plant sites and/or sold to customers. We further assume that a storage unit is connected to all processing and transportation stages that consume/produce or move the material to which that storage unit is dedicated. Each processing stage transforms a set of feedstock materials or intermediates into a set of products with constant conversion factors. A batch transportation process can transfer one material or multiple materials at once between plant sites. The objective for optimization is to minimize the probability averaged total cost composed of raw material procurement, processing setup, transportation setup and inventory holding costs as well as the capital costs of processing stages and storage units. A novel production and inventory analysis formulation, the PSW(Periodic Square Wave) model, provides useful expressions for the upper/lower bounds and average level of the storage inventory. The expressions for the Kuhn-Tucker conditions of the optimization problem can be reduced to two sub-problems. The first yields analytical solutions for determining lot sizes while the second is a separable concave minimization network flow subproblem whose solution yields the average material flow rates through the networks for the given demand forecast scenario. The result of this study will contribute to the optimal design and operation of large-scale supply chain system.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.355-362
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• 1999

With the ready access to the high resolution satellite image data, users of and areas covered by satellite image data are constantly on the rise world-wide. Korea will also be able to take full advantage of the satellite data once the KOMPSAT is successfully launched. Harmonizing satellite data production and application technology and users' needs, along with the guiding policy is essential for promoting satellite data use. Up to now, the Korean government has mainly concentrated on developing production technology for the satellite units. However, the imminent task of independent satellite data production demands a promotion policy for satellite data use. In this context, the policy is defined as an important medium for identifying the role and status of satellite image information at the national level and also Preparing the legal as well as systematic foundation for producing, building, distributing, and packaging satellite data. For example, in the countries with the advanced satellite technology, such as the United States, the United Kingdom, and Australia, digital ortho image and digital elevation model (DEM) are mandatorily included in the National Geographic Framework Data through policy measures. In addition, in order for the efficient provision of the satellite data, separate organization or agency is being in operation for the exclusive production and distribution of the satellite data. The present paper aims to examine the role and status of the satellite data as well as their current status and problems in Korea in reference to the National Spatial Data Infrastructure, and finally to provide the policy directions to promote the satellite data use in public sector on the basis of the preceding analyses.

• Journal of Korean Neurosurgical Society
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• v.42 no.4
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• pp.300-304
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• 2007

Objective : We report experiences and clinical outcomes of 61 cases with spinal canal meningiomas from January 1970 through January 2005. Methods : Thirty-eight patients were enrolled with follow-up duration of more than one year after surgery. There were 7 male and 31 female patients. The mean age was 52 years (range, 19 to 80 years). All patients underwent microsurgical resection using a posterior approach. Results : Twenty-nine (79.4%) cases experienced clinical improvement after surgery. The extent of tumor resection at the first operation was Simpson Grade I in 10 patients, Grade II in 17, Grade III in 4, Grade IV in 6, and unknown in one. We did not experience recurrent cases with Simpson grade I, II, or III resection. There were 6 recurrent cases, consisting of 5 cases with an extent of Simpson grade IV and one with an unknown extent. The mean duration of recurrence was 100 months after surgery. Radiation therapy was administered as a surgical adjunct in four patients (10.5%). Two cases were recurrent lesions that could not be completely resected. The other two cases were malignant meningiomas. No immediate postoperative death occurred in the patient group. Conclusion : We experienced no recurrent cases of intraspinal meningiomas once gross total resection has been achieved, regardless of the control of the dural origin. Surgeons do not have to take the risk of causing complication to the control dural origin after achieving gross total resectioning of spinal canal meningioma.

• Journal of KIISE:Information Networking
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• v.28 no.4
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• pp.602-610
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• 2001

In the MPLS(Multiprotocol Label Switching) forwarding paradigm, once a packet is assigned to a FEC(Forwarding Equivalence Class), no further header analysis is done by subsequent routers; all forwarding is driven by the labels. This has a number of advantages over conventional network layer forwarding. The MPLS LER(Label Edge Router) is located at the boundary of MPLS domain and plays a role in connecting with the existing Internet as an ingress or an egress router. That is, the MPLS LER as an ingress router assigns a label to a packet which enters the MPLS network from the Internet by analyzing its header and forwards to a corresponding next router in MPLS domain. As an egress router, the MPLS LER turns the packets out of the MPLS network by performing the reverse operation. In this paper, we analyze the traffic performance of an MPLS LER system and estimate the IP(Internet Protocol) packet processing capacity of the system using queueing model and simulation. It is found that the maximum IP packet processing capacity of the system is estimated by 420,000 through 460,000 packets/sec.

• Journal of Korean Society on Water Environment
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• v.21 no.5
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• pp.458-463
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• 2005

Considering the characteristics of a filtration bio-reactor equipped with a mesh filter module which can effectively maintain high concentration of biomass and enhanced solid-liquid separation performance, the hybrid process of filtration bio-reactor combined with coagulation was investigated to get improved filtration characteristics as well as water quality in this work. Two bio-reactors (Run-1 & Run-2) were operated under the following conditions: working volume of 25 L, continuous loading of a synthetic wastewater (BOD: 200 mg/L, T-N: 50 mg/L, T-P: 5 mg/L), where an appropriate amount of alum ($Al_2(SO_4)_3{\cdot}18H_2O$) was added once a day into the reactor (Run-2). In the system without using a alum (Run-1), the clogging of mesh filter module was observed two times through 85 days of whole operation. Meanwhile, the filter module did not clog even at higher MLSS concentration (6,000~12,000 mg/L) and the stable filtration (0.7 mid) was continued in the case of using a alum. Due to the stable formation of cake layers, BOD and SS were shown below 6 and 3 mg/L, respectively. T-P and pH of the effluent were changed because of the intermittent addition of the alum. In the case of Al/P=2.5, the average T-P removal efficiency per day was 85.2% and the average T-P concentration of the effluent was 0.3 mg/L. However, the removal efficiency of phosphate was influenced by pH in the reactor.

• THE INDUSTRY AND TECHNOLOGY OF GAS
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• v.5 no.1 s.6
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• pp.39-47
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• 2002

With the expansion of natural gas demands in many countries, the necessity of LNG receiving terminals has been increased. The offshore LNG Floating Storage and Regasification Unit (FSRU) attracts attentions not only for a land based LNG receiving terminal alternative, but also for a feasible and economic solution. Nowadays, as the reliability of offshore oil and gas floating facilities and LNG carriers gains with proven worldwide operations, the FSRU can achieve a safety level that can be comparable to an onshore terminal. The design development related with safety features of the FSRU has been extensively carried out by oil and gas companies, shipyards, engineering companies, and equipment vendors, and has been successful so far in many fields. The construction of the FSRU can be achieved by integrating various technologies and experiences from many disciplines and many participating companies and vendors. In this paper, reviews on some of the important design features and design improvements on FSRU together with the practical construction aspects in cargo containment, vaporization system, ESD system, and operation modes, have been covered in comparison with actual LNG carrier, onshore receiving terminal, and FPSO systems. In order to materialize an FSRU project, the technical and economic justification has to be preceded. It is believed that once the safety and technical soundness is convinced, the FSRU can bring a higher project feasibility by reducing the overall construction time and cost. Through this study, an FSRU design readily applicable to an actual project has been developed by incorporating experiences gained from many marine and offshore projects. The wide use of proven standard technologies adopted in the series construction of LNG carriers and offshore FPSOs will bring the project efficiency and reliability.

• The Korean Journal of Emergency Medical Services
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• v.6 no.1
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• pp.15-26
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• 2002

As a result of analyzing problems in field practice and its effects, the following conclusions can be obtained. Man students were more satisfied with their choice of this department than woman students and woman students recognized the importance of hospital practice although they felt the need of fire fighting station practice and man students felt the necessity of hospital practice, but they answered the fire fighting station practice was important. Departments of field practice are emergency and nurse departments in hospitals and emergency aid section in fire fighting stations. And it is found that field practice was performed well in relation to major subject. Areas of practice included emergency room, operation room and extensive cure unit and the experience of ambulance was more in fire fighting station than in hospital. Clinical guidance of professor was preferred to once a week and the students answered they felt satisfaction with practice through conference. Answer that field practice was helpful in understanding class was very high as 96.8% and its connection with employment was low as 12.8%. It is found that a proper timing of field practice was winter vacation for hospital practice after completing the second semester of the first year and summer vacation for fire fighting station practice after the first semester of the second year. The most difficult department in field practice was nurse department in hospital because 'respondents were practice students' and administrative department in fire fighting stations because 'they lacked recognition of paramedic'. In making practice diary, 'describing measure results' was difficult most and the respondents wanted to keep the diary in their custody.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.6
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• pp.537-544
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• 2004

An effective methodology is reported for determining the optimal lot size of batch processing and storage networks which include uncertain demand forecasting. We assume that any given storage unit can store one material type which can be purchased from suppliers, internally produced, infernally consumed, transported to or from other sites and/or sold to customers. We further assume that a storage unit is connected to all processing and transportation stages that consume/produce or move the material to which that storage unit is dedicated. Each processing stage transforms a set of feedstock materials or intermediates into a set of products with constant conversion factors. A batch transportation process can transfer one material or multiple materials at once between sites. The objective for optimization is to minimize the probability averaged total cost composed of raw material procurement, processing setup, transportation setup and inventory holding costs as well as the capital costs of processing stages and storage units. A novel production and inventory analysis formulation, the PSW(Periodic Square Wave) model, provides useful expressions for the upper/lower bounds and average level of the storage inventory. The expressions for the Kuhn-Tucker conditions of the optimization problem can be reduced to two sub-problems. The first yields analytical solutions for determining lot sires while the second is a separable concave minimization network flow subproblem whose solution yields the average material flow rates through the networks for the given demand forecast scenario. The result of this study will contribute to the optimal design and operation of the global supply chain.

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.752-759
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• 2010

In this paper, we propose differential-logging method to improve the performance of RMW(Read Modify Write) operations of DDR-SSD based software RAID. Small writes that are frequently occurred in enterprise applications are main factor to degrade the performance of RAID5. Once a block is updated in RAID5, the parity block of the block must be updated to maintain consistency of parity. Therefore, to process a small write request, we need to read its parity block stored in disk, read old data, perform XOR operation, and write updated data and parity block. Several methods for hard disk based software RAID are proposed to solve the small write problems in RAID 5. Ln this paper, we propose a differential-logging method which carefully considers the DDR-SSD to solve the small write problem in RAID 5. We show that our proposed method out performs the existing software RAID in LINUX through simulations.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.6
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• pp.970-975
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• 2010

Because Lonicerae Flos has effects of antiinflammatory and antioxidant, we studied an effect of Lonicerae Flos on reflux esophagitis (RE) through those effects. Rats were treated with three different dosages of LF (500, 250 and 125 mg/kg) orally for 14 days before pylorus and forestomach ligation. Six hrs after pylorus and forestomach ligation, we dissected a stomach and examined a stomach volume, gastric acid output, pepsin release in the stomach, total hexose, sialic acid in stomach tissue and histamine contents of sera. The results were compared with an ${\alpha}$-tocopherol (once orally, 1hr before operation, 30 mg/kg) treated group in which the effects on RE were already confirmed. Lonicerae Flos extract (LE) reduced gastric volumes compared to RE control. This indicate that LE protect a stomach mucosa by depressing of gastric acid release and corresponse with a reducing histamine content of serum. And LE decreasd a volume of pepsin in stomach compraed to RE control, LE increased contents of total hexose and sialic acid based on esophageal and gastric mucus. This indicated that an increased mucus by LE protected inflammation of esophagus mucosa and gastric mucosa induced by gastric acid. So, LE suppressed a gasric acid by decreasing a pepsin release in stomach, suppressed an injury of esophagus inducted by gastric acid with increasing esophageal mucus and a minimum dose of LE to RE was 250 mg/kg. The results suggest that antioxidant effects of LF could attenuate the severity of reflux esophagitis and prevent the esophageal mucosal damage, and validate its therapeutic use in esophageal reflux disease.