• Journal of Korean Neurosurgical Society
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• v.30 no.5
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• pp.581-585
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• 2001

Objectives : Criteria for evaluating the results of treating low back pain vary widely. We examined the methods measuring the outcome in the papers of Journal of Korean Neurosurgical Society. Methods : We selected all published articles describing the methods measuring the outcome of low back pain in the journal. They were classified into 3 periods such as period 1 for volume 1-20, 2 for volume 21-25, and 3 for volume 26-28. Results : There are 25 articles in period 1, 44 in period 2, and 30 in period 3. The outcome was classified into 0 to 5 classes by more than 15 different methods. Although the terms and descriptive criteria differ, 4 classes were the most common classification, being 16 in period 1, 39 in period 2, and 19 in period 3. The outcome was usually measured by authors' own method in period 1. In period 2, criteria by Gill et al was most commonly used along with many different criteria. Criteria by Prolo et al became a common method in period 3. Conclusion : Varying methods compromised comparative analyses of outcome. A more simple and universally applicable criteria is necessary to facilitate comparisons among various methods of treatment.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.5
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• pp.682-689
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• 2011

Recently, there are frequent disasters by Swell-like Wave in the coastal area, Korea peninsula. This phenomenon (Swell-like Wave) has long period above 10 seconds compared with wind wave. To prevent these disasters by the long-period wave in advance, it's necessary to observe it in real time. But existing instruments for wave observation can not observe long-period wave because they mainly are aimed to measure the short-period wind wave. Therefore, in this research it is tried to develop the GPS based Long Period Wave Observation System which real time operation can be realzied in the sea.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.6
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• pp.111-117
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• 2005

The period of a recent streamcipher proposal Edon80 is analyzed. The designers of Edon80 had projected a period of $2^{103}$ Even though this could indeed be the average keystream Period, we show that for a randomly chosen key-IV pair, there exists a non-dismissible probability that the produced keystream will be of relatively short period. More explicitly, a keystream of period. $2^{55}$ may appear with probability $2^{-71}$, and one can show the existence of at least one key-lV pair producing a period $2^{11}$ keystream.

• Journal of the Korean Geographical Society
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• v.51 no.1
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• pp.127-142
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• 2016

This paper analyzes on the physical place name of Mt. Seoraksan in Joseon period from the historical geographical perspective. The analysis materials are Jirijis, old maps and travel records of Joseon period. The results are as follows. The space range of Mt. Seoraksan in Joseon period and today was different. Mt. Seoraksan in Joseon period was around Daecheongbong Peak nowadays, Ulsanbawi Rock was Mt. Cheonhusan, and north mountain range of Hangyeryeong Pass called Mt. Hangyesan. Region of Mt. Seoraksan and Mt. Hangyesan were devided in Joseon Period. Mt. Seoraksan name was representative in late Joseon period including Mt. Hangyesan and Mt. Cheonhusan. Mountain names were the most in the physical place name. The old name of Hangyeryeong Pass was Osaek Pass in maps of Joseon Period. The popular travel course of Mt. Seoraksan in Joseon period was Baekdamsa Temple-Oseam Temple-Sinheungsa Temple.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.3
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• pp.173-183
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• 1993

Four wave gauges of pressure type were installed for about one month(1992. 2~3) for the analysis of wave agitations induced by the intrusion of long-period incident waves inside and outside of Donghae Harbor. Helmholtz natural period and second peak period of seiche in Donghae Harbor are found to be approximately 17.1 and 5.5 minutes from the spectral analysis of measured long-period wave data. Amplification ratio at Helmholtz natural period reaches about 10 which is five times as lagre as that of Youngil Bay, but wave amplitudes ill harbor were about 10 em during the measurement period which are relatively small.

• Journal of Korean Neurosurgical Society
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• v.59 no.4
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• pp.379-384
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• 2016

Objective : Mechanical thrombectomy (MT) for acute intracranial internal carotid artery (ICA) occlusion is often complicated by difficult revascularization and non-involved territory embolization possibly related with larger clot-burden. This study aims to evaluate the efficacy of proximal aspiration thrombectomy (PAT) using a balloon-tipped guide catheter for clot-burden reduction in such cases with period-to-period analysis (period 1 : standard MT without PAT; period 2 : PAT first, then standard MT for the remaining occlusion). Methods : Eighty-six patients who underwent MT for acute intracranial ICA occlusion were included in this analysis from the prospectively maintained stroke registry (33 patients in period 1 and 53 in period 2). In period 2, 'responder' was defined as a case where some amount of clot was retrieved by PAT and the following angiography showed partial or full recanalization. Results : Fifteen of fifty-three patients in period 2 (28.3%) were 'responders' to PAT. There was a significantly higher incidence of atrial fibrillation in the 'responder' subgroup. Period 2 showed a significantly shorter puncture-to-reperfusion time (94.5 minutes vs. 56.0 minutes; p=0.002), a significantly higher Thrombolysis in Cerebral Infarction of 2b-3 reperfusion (45.5% vs. 73.6%; p=0.009), but only a trend for better 3-month favorable outcome (mRS 0-2; 36.4% vs. 54.7%; p=0.097). There was no increase in the incidence of procedure-related complications or intracranial hemorrhage in period 2. Conclusion : A strategy of PAT before standard MT may result in shorter puncture-to-reperfusion time and better angiographic outcome than a strategy of standard MT for acute intracranial ICA occlusion.

• Journal of the Korean housing association
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• v.5 no.2
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• pp.41-50
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• 1994

The purpose of this study is to investigate changes of the kitchen lifespace in Korean family houses from the Old Stone Age to the Koryo Dynasty. The documentary research method was used for this study. The major findings were as follows the changes of kitchen lifespace in Korean family houses form the Old Stone Age to the Koryo Dynasty have been affected by natural, political, economic, technological, and socio-cultural environments. The Kitchen lifespace of these periods was categorized into six categories: the Beginings Period of the Kitchen, the Period of the Primitive Kitchen, the Formative Period of the Kitchen, the Enlargement Period of the Kitchen, the Separation Period of the Kitchen, and the Begining Period of the Traditional Kitchen.

• International Journal of Advanced Culture Technology
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• v.9 no.3
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• pp.271-276
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• 2021

In this paper we analyze the effect of the credit period on inventory policy under trade credit with ordering cost including a fixed cost and freight cost, where the freight cost has a quantity discount. For marketing purposes, some supplier offers credit period to his buyer to stimulate the demand for the product he produces. The delay in payments during the credit period has the effect of reducing the buyer's capital opportunity cost. It is also assumed that the buyer pays the freight cost for the order and hence, the ordering cost consists of a fixed ordering cost and a variable freight cost which depends on the order quantity. As a result, the possibilities of trade credit and discounts on freight costs are expected to play an important role in the buyer's inventory policy. Based on the economic order quantity inventory model, we analyze how the buyer can determine the optimal inventory policy and we examine the effect of the length of credit period on the buyer's inventory policy.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.938-946
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• 2005

We study the firm's strategy to price its products and plan the spare parts manufacturing so as to maximize its profit and at the same time to fulfill its commitment to providing the customers with the key parts continuously over the relevant decision time horizon, i.e., the production plus warrantee period. To examine the research question, we developed and solved a two-stage optimal control theory model. Our analysis suggests that if the cost to produce the spare part during the warrantee period is more expensive than that during the production period, the firm should increase its sales price gradually throughout the production period to control its sales. In addition, during the production period it is optimal for the firm to produce the spare parts more than needed so that the overproduced spare parts can be used to partially meet the demand during the warrantee period. We conducted numerical analysis to investigate the sensitivity dynamics among key variables and parameters such as inventory holding cost, unit spare part production costs, part failure rate, and parameters in the demand function.

• International Journal of Reliability and Applications
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• v.18 no.1
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• pp.1-8
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• 2017

In this paper, we study an extended warranty model under minimal repair-replacement warranty (MRRW) which is suggested by Park, Jung and Park (2013). Under MRRW policy, the manufacturer is responsible for providing the minimal repair-replacement services upon the system failures during the warranty period. And if the failure occurs during the extended warranty period, only the minimal repair is conducted. Following the expiration of extended warranty, the user is solely responsible for maintaining the system for a fixed length of time period and replaces the system at the end of such a maintenance period. During the maintenance period, only the minimally repair is given for each system failure. The main purpose of this article is to suggest the extended warranty and replacement model with MRRW. Given the cost structures incurred during the life cycle of the system, we formulate the expected cost and the expected length of life cycle to obtain the expected cost rate.