• 대한산업공학회지
• /
• 제32권3호
• /
• pp.180-190
• /
• 2006

We evaluate the economic value and the optimal investment timing of IMT-2000 in Korea, in the perspective of a service provider who owns the business license for IMT-2000, by using the real options analysis. The result clearly shows the project value with options is positive and delaying the investment is more favorable to the provider. Binomial lattice approach, in which we try to describe American call option and sequential compound option, and sensitivity analysis present the optimal decisions according to future states and enable the management to make decision strategically and proactively.

• Asian Journal of Innovation and Policy
• /
• 제7권3호
• /
• pp.581-605
• /
• 2018

In the soft drink industry, especially small and medium enterprises in Japan, there is a possibility of conversion from a labor-intensive industry to a capital-intensive. The demand for soft drinks may not be satisfied in the summer because the supply is too low to meet the demand. To address this situation, this paper proposes optimal investment that integrates demand uncertainty, based on real options approach (ROA) and seasonal autoregressive integrated moving average. Two alternative options are compared and evaluated. One is the Bermudan option: to employ additional workers to elevate efficiency in summer and laying off in winter, this attitude is repeated each year. The other is the American option: to replace equipment to increase machine ability throughout the year. Results in ROA show that the highest improvement is gained if the two options are in a symbiotic relationship. Soft drink producers should search for replacing equipment, using the employees repeatedly. A temporary decision is not equal to an infinite decision.

• 대한수학회보
• /
• 제48권2호
• /
• pp.413-426
• /
• 2011

Two types of new methods with variable time steps are proposed in order to valuate binary options efficiently. Type I changes adaptively the size of the time step at each time based on the magnitude of the local error, while Type II combines two uniform meshes. The new methods are hybrid finite difference methods, namely starting the computation with a fully implicit finite difference method for a few time steps for accuracy then performing a ${\theta}$-method during the rest of computation for efficiency. Numerical experiments for standard European vanilla, binary and American options show that both Type I and II variable time step methods are much more efficient than the fully implicit method or hybrid methods with uniform time steps.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 C
• /
• pp.1769-1773
• /
• 1996

The remaining life of generator stator winding has been the controversial issue amomg many experts in this area. The report from Japan claims that they can predict the remaining life of generator winding, while the North American has the negative opinion about it. This study aimed at verifying the validity of both Japanese criteria and North American argument on evaluation of generator winding insulation. Non destructive and destructive tests were performed on two hydro-generators. The test results showed that the trend analysis of stator winding insulation was the better option.

• The Korean Journal of Pain
• /
• 제30권2호
• /
• pp.93-97
• /
• 2017

The sphenopalatine ganglion (SPG) is a parasympathetic ganglion, located in the pterygopalatine fossa. The SPG block has been used for a long time for treating headaches of varying etiologies. For anesthesiologists, treating postdural puncture headaches (PDPH) has always been challenging. The epidural block patch (EBP) was the only option until researchers explored the role of the SPG block as a relatively simple and effective way to treat PDPH. Also, since the existing evidence proving the efficacy of the SPG block in PDPH is scarce, the block cannot be offered to all patients. EBP can be still considered if an SPG block is not able to alleviate pain due to PDPH.

• Journal of Chest Surgery
• /
• 제54권6호
• /
• pp.449-453
• /
• 2021

The 2020 American College of Cardiology focused update on the mitral regurgitation (MR) pathway provides an excellent summary of the decision-making trees in the treatment of severe MR, in which 2 main branches of the flowchart are suggested depending on whether MR is primary or secondary. Surgery is suggested as preferable over transcatheter edge-to-edge repair (TEER) in primary MR that needs intervention. The decision-making for secondary MR generally prioritizes TEER over surgery according to the guidelines, but further stratification is necessary based on the pathophysiologic mechanisms of MR. TEER is probably the more suitable option in secondary MR caused by left ventricular dysfunction or dilatation, given the high perceived surgical risks, despite the lack of sufficient evidence in support of overt clinical benefits from surgical therapy in these patients. In atrial functional MR associated with atrial fibrillation (AF), however, concomitant ablation of AF seems to be a desirable option, as it has been demonstrated to be a key factor leading to improved survival, reduced stroke risk, and more durable mitral and tricuspid function in patients undergoing mitral surgery. Therefore, atrial functional MR requiring intervention may be best treated by surgical therapy that combines mitral repair and AF ablation in the majority of patients. This particular issue, however, needs further research to obtain scientific evidence to guide optimal management strategies.

• Communications for Statistical Applications and Methods
• /
• 제15권4호
• /
• pp.563-585
• /
• 2008

본 연구는 다양하고 복잡해지는 파생상품 추세에 상응하는 적절한 가치평가에 대한 연구의 필요성을 인지하고 가격 및 민감도 평가에 있어서 속도와 정확도를 향상시키는데 그 의의를 두고자 한다. 몬테카를로 시뮬레이션에서 의사난수 대신 저불일치수열인준난수를 이용하면 시행횟수의 감소와 정확도 개선이 가능한데, 미국형 옵션이나 경로의존형 상품 등 다차원의 난수가 필요할 경우 기존의 준난수를 사용하면 상관관계가 증가하는 문제로 적용에 한계가 있다. 이런 단점을 보완하기 위해 문제를 발생시키는 차원의 난수를 제외시켜 상관계수를 특정값 이하로 제어하는 새로운 방법을 고안하여 다차원 상품에 적용이 가능토록 하였고 미국형 풋옵션에 적용하여 새로운 방법의 유용성을 검증하였다. 또한, 몬테카를로 시뮬레이션에서 민감도 계산방법으로 우도비율법과 경로의존형 근사방법을 사용하면 속도 및 정확도가 개선됨을 보인다. 이러한 결과는 최근 시장의 추세인 기초자산이나 위험요소가 여러 개인 경우 그리고 경로의존형 및 조기상환형 상품 등에 적용 가능토록하여 몬테카를로 시뮬레이션 방법에 있어 가장 큰 단점으로 지적되는 수행시간을 단축시키고 민감도 계산의 오차를 줄여줌을 보여준다. 또한, 2개 이하의 기초자산으로 이루어진 파생상품의 가치 및 민감도 평가에 가장 효율적인 수치해석적 방법론으로 알려져 있는 유한차분법의 적용시 격자생성구간의 설정이 매우 중요하다는 사실을 비대칭 나비형스프레드에 적용하여 실증적으로 보인다.

• 대한족부족관절학회지
• /
• 제19권2호
• /
• pp.58-62
• /
• 2015

Purpose: The purpose of this report is to investigate the clinical and radiological results of corrective osteotomy of the 3rd metatarsal bone for shortening and dorsal displacement without exposure around neuroma. Materials and Methods: Twelve cases of patients who underwent corrective osteotomy of metatarsal bone for a Morton's neuroma from November 2013 to September 2014 were retrospectively reviewed. Corrective osteotomy was performed through a dorsal approach at the 3rd metatarsal bone base and distal metatarsal bone was displaced dorsally and proximally. Preoperative and postoperative pain assessed using American Orthopaedic Foot and Ankle Society (AOFAS) score and radiographs were evaluated. Results: The mean age of patients was 41.4 years, and the mean follow-up period was 10.7 months. AOFAS score improved from 52 preoperatively to 90 postoperatively. The 3rd metatarsal bone was shortened by an average of 3.39 mm and elevated by 2.38 mm. Conclusion: Corrective osteotomy of metatarsal bone can be regarded as a new surgical option for Morton's neuroma without exposure around neuroma.

• Journal of Ginseng Research
• /
• 제29권2호
• /
• pp.71-79
• /
• 2005

In vitro studies using detached inflorescences with peduncles were conducted to investigate flower abscission agents in North American ginseng (Panax quinquefolius L.). Of the nine compounds studied only three, ammonium thiosulphate (ATS), abscisic acid (ABA) and ethephon induced abscission. Anilazine, benzyladenine, carbaryl, gibberellic acid, napthaleneacetic acid and thidiazuron did not induce abscission. ATS dip treatments did not induce abscission but the spray treatments induced $60.5\%$ abscission at $1500\;mg{\cdot}L^{-1}$ and $33.1\%$ at $3000\;mg{\cdot}L^{-1}$. Severe chlorophyll loss occurred on all inflorescences treated with ATS. Both ABA dip treatments and a $250\;{\mu}mol{\cdot}L^{-1}$ spray treatment caused abscission $(40\%)$ without adverse effects, and timing of ABA application was important. Because ABA was only significant in the dip treatments, ABA may not be a practical option for field use on ginseng. Ethephon sprays induced more abscission as the season progressed and as the concentration increased. As the dip concentrations of ethephon increased, the abscission rate decreased and the health of the inflorescences declined. The $1500\;mg{\cdot}L^{-1}$ spray of ethephon gave consistent abscission results over the glowing season with little phytotoxicity. Treatment with the competitive ethylene inhibitor 1-methylcy-clopropene (1-MCP) suggested that flower abscission was due to the liberation of ethylene from the breakdown of ethephon.

• 한국임상약학회지
• /
• 제26권1호
• /
• pp.59-69
• /
• 2016

Background: The subcutaneous formulation of biologic disease-modifying antirheumatic drugs (DMARDs) was preferred due to favored self-administration and would be an economical treatment option for patients with rheumatoid arthritis. This study was to compare the economic impact of biologic DMARDs administered by subcutaneous injection in patients with rheumatoid arthritis who had inadequate response to conventional DMARDs. Methods: The cost-minimization analysis was conducted to estimate the lifetime health care costs of treatment sequences with subcutaneous biologic DMARDs as first-line therapy from a health care system perspective. The Markov model was developed to represent the transitions through treatment sequences based on American College of Rheumatology response rate and discontinuation rate. The health care costs comprised the cost of medications, administration, dispensing, outpatient visits, test/diagnostic examination, palliative therapy and treatment of serious infection. All costs were expressed in 2016 Korean Won (KRW) and discounted at 5%. Results: The mean lifetime health care cost per patient was lowest in the etanercept sequence, which was estimated at KRW 63,441,679. The incremental costs of the treatment sequence started with adalimumab, golimumab, abatacept, and tocilizumab were KRW 7,985,730, KRW 4,064,669, KRW 2,869,947, and KRW 4,282,833, respectively, relative to etanercept sequence. These differences in costs mainly were attributable to medication costs. One-way and probabilistic sensitivity analyses confirmed that etanercept represented the option with the lowest cost compared with comparators. Conclusion: This study found that etanercept is likely a cost-saving treatment option among subcutaneous biologic DMARDs in patients with rheumatoid arthritis.