• Asia-Pacific Journal of Business
• /
• v.11 no.3
• /
• pp.243-260
• /
• 2020

Purpose - This paper aims to investigate the properties of crude oil based derivative security (DLS) focusing on step-down type for comprehensive understanding of its risk. Design/methodology/approach - Kernel estimation is conducted to figure out statistical feature of the process of oil price. We simulate oil price paths based on kernel estimation results and derive probabilities of hitting the barrier and early redemption. Findings - The amount of issuance for crude oil based DLS is relatively low when base prices are below $40 while it is high when base prices are around $60 or $100, which is not consistent with kernel estimation results showing that oil futures prices tend to revert toward $46.14 and the mean-reverting speed is faster as oil price is lower. The analysis based on simulated oil price paths reveals that probability of early redemption is below 50% for DLS with high base prices and the ratio of the probability of early redemption to the probability of hitting barrier is remarkably low compared to the case for DLS with low base prices, as the chance of early redemption is deferred. Research implications or Originality - Empirical results imply that the level of the base price is a crucial factor of the risk for DLS, thus introducing a time-varying knock-in barrier, which is similar to adjust the base price, merits consideration to enhance protection for DLS investors.

• Archives of Plastic Surgery
• /
• v.49 no.2
• /
• pp.174-183
• /
• 2022

Management of traumatic skull base fractures and associated complications pose a unique reconstructive challenge. The goals of skull base reconstruction include structural support for the brain and orbit, separation of the central nervous system from the aerodigestive tract, volume to decrease dead space, and restoration of the three-dimensional appearance of the face and cranium with bone and soft tissues. An open bicoronal approach is the most commonly used technique for craniofacial disassembly of the bifrontal region, with evacuation of intracranial hemorrhage and dural repair performed prior to reconstruction. Depending on the defect size and underlying patient and operative factors, reconstruction may involve bony reconstruction using autografts, allografts, or prosthetics in addition to soft tissue reconstruction using vascularized local or distant tissues. The vast majority of traumatic anterior cranial fossa (ACF) injuries resulting in smaller defects of the cranial base itself can be successfully reconstructed using local pedicled pericranial or galeal flaps. Compared with historical nonvascularized ACF reconstructive options, vascularized reconstruction using pericranial and/or galeal flaps has decreased the rate of cerebrospinal fluid (CSF) leak from 25 to 6.5%. We review the existing literature on this uncommon entity and present our case series of n = 6 patients undergoing traumatic reconstruction of the ACF at an urban Level 1 trauma center from 2016 to 2018. There were no postoperative CSF leaks, mucoceles, episodes of meningitis, or deaths during the study follow-up period. In conclusion, use of pericranial, galeal, and free flaps, as indicated, can provide reliable and durable reconstruction of a wide variety of injuries.

• Korean Institute of Interior Design Journal
• /
• no.11
• /
• pp.70-73
• /
• 1997

This paper explores ways to develop efficient methods to construct the web-based interior design database based on hypermedia technology. First the role of hypermedia in design was investigated. We propose the structure of knowledge representation for interior design works. Also, we discuss how a design case can be retrieved from the design database. This paper also identified further research issues such as design case retrieval from numerous design cases and components of the virtual design studio.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.10 no.2
• /
• pp.75-82
• /
• 1985

Reorganization is essential part of data base maintenanc work and the reasonable reorganization points can be determined from the trade-off between reorganization cost and performance degradation. There has been many reorganization models so far, but none of these models have assumed nonlinear search cost function. This paper presents the existensions of two existing linear reorganization models for the case where the search cost function is quadratic. The higher performance of these extended models was shown in quadratic search cost function case.

• Korean Journal of Bronchoesophagology
• /
• v.1 no.1
• /
• pp.164-167
• /
• 1995

Foreign holies in the upper aerodigestive tract are an important cause of morbity and mortality in older adults and children under 3 years of age. Fish and chicken bones are the usual foreign bodies lodged in the hypopharynx, and most of them lodge In the lower pole of a tonsil, at the base of the tongue, at the lateral wall of the pharynx, or in a vallecula. Recently, the authors experienced a case of aspiration pneumonia caused by chronic local inflammatory reaction of the posterior wall of the hypopharynx originated from a special foreign body.

• The Journal of the Korean dental association
• /
• v.15 no.2
• /
• pp.111-114
• /
• 1977

The case of the extensive dentigerous cyst treated by intubation technique is reported. 1) An incision is made, and the sterile polyethylene tube is inserted into the prepared opening so that it gently contacts the base of the lesion in 11 year old man. 2) The purpose to maintain vitality of adjacent tooth was achieved by means of intubation in lesion. 3) After 9 months, the extensive periapical lesion was completely replaced with new bone tissue.

• Proceedings of the Korean Information Science Society Conference
• /
• 2003.10a
• /
• pp.70-72
• /
• 2003

주어진 현재의 문제를 해결하기 위해서 과거에 유사하게 수행된 사례를 유추하여 유추된 사례의 해를 이용하는 사례 기반 추론(case-base reasoning)은 털러 분야에 응용되고 있지만, 사례기반 추론 시 새로운 사례를 해결하기 위하여 사례베이스 내의 모든 사례를 검색해야 하기 때문에 수행시간이 증가되는 단정을 지니고 있다. 본 연구에서는 하드 클러스터링 방법으로 완전하게 분류하는 것이 불가능할 수도 있다는 문제점을 개선시키기 위하여 퍼지 클러스터링을 방법을 이용하여 사례베이스를 분류함에 의하여 시스템의 수행시간을 감소시키면서 정확성을 높이게 되었다.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.60 no.4
• /
• pp.241-245
• /
• 2011

In this paper, when photovoltaic (PV) systems are connected to power distribution system, most effective capacity and connected-point of PV system are presented considering power distribution system reliability. The reliability model of PV system is presented considering the duration of sunshine. Also the model of time-varying load and reliability test system bus2 model are used. To simulate the effects of PV system, various cases are selected; (1) base case which is no connection of PV system to power distribution system when faults are occurred, (2) 3MW case which is 3[MW] connection of PV system (3) 4[MW] case, and (4) 20[MW] case which is 20[MW] connection of PV system to the bus of power distribution system. The capacity limit of connected PV system is settled to 14[MW] for all cases except case 4. The reliability for residential, general, industrial, and educational customer is evaluated.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.7
• /
• pp.163-170
• /
• 2004

In order to automatically determine the sequences of block assembly operations in shipbuilding, a process planning system using case-based reasoning (CBR) is developed. A block-assembly planning problem is modeled as a constraint satisfaction problem where the precedence relations between operations are considered constraints. The process planning system generates an assembly sequence by adapting information such as solutions and constraints collected from similar cases retrieved from the case base. In order to find similar cases, the process planning system first matches the parts of the problem and the parts of each case based on their roles in the assembly, and then it matches the relations related to the parts-pairs. The part involved in more operations are considered more important. The process planning system is applied to simple examples fur verification and comparison.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.1C
• /
• pp.59-68
• /
• 2002

In this paper we issue some problems occurring when a mobile host moves from a base station to another in a wireless multicasting and propose a solution. In the case of not being in the same multicast group, the old base station will pre-forward data to neighboring base stations to avoid transmission delay. However, if other mobile hosts move at short interval, the old base station may retransmit the same dta to the same neighboring base stations. Also, the old base station should retransmit data if the new base station has already discarded data even if the new base station is a member of the multicast group. In this paper we propose called Information Exchange Scheme (IES). In this scheme, each base station exchanges indirectly the data delivery information with the rest of the base stations in the same multicast group for efficient and reliable multicast and pre-forwards data not retransmitting the same data for minimizing transmission delay when a mobile host moves. We also present how IES is efficient by analyzing and simulating.