• Bulletin of the Korean Mathematical Society
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• v.53 no.1
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• pp.21-28
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• 2016

It is known that no two of the roots of the polynomial equation (1) $$\prod\limits_{l=1}^{n}(x-r_l)+\prod\limits_{l=1}^{n}(x+r_l)=0$$, where 0 < $r_1{\leq}r_2{\leq}{\cdots}{\leq}r_n$, can be equal and all of its roots lie on the imaginary axis. In this paper we show that for 0 < h < $r_k$, the roots of $$(x-r_k+h)\prod\limits_{{l=1}\\{l{\neq}k}}^{n}(x-r_l)+(x+r_k-h)\prod\limits_{{l=1}\\{l{\neq}k}}^{n}(x+r_l)=0$$ and the roots of (1) in the upper half-plane lie alternatively on the imaginary axis.

• Bulletin of the Korean Mathematical Society
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• v.51 no.6
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• pp.1591-1603
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• 2014

In this paper, we investigate maximum principle, convergence of sequences and angular limits for harmonic Bloch mappings. First, we give the maximum principle of harmonic Bloch mappings, which is a generalization of the classical maximum principle for harmonic mappings. Second, by using the maximum principle of harmonic Bloch mappings, we investigate the convergence of sequences for harmonic Bloch mappings. Finally, we discuss the angular limits of harmonic Bloch mappings. We show that the asymptotic values and angular limits are identical for harmonic Bloch mappings, and we further prove a result that applies also if there is no asymptotic value. A sufficient condition for a harmonic Bloch mapping has a finite angular limit is also given.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.10a
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• pp.109-112
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• 2000

This paper presents an analytical study that can predict the path-dependent forming limits for bilinear strain paths. To predict the forming limit diagrams(FLD), the analytical procedure was performed within the framework of Marciniak and Kuczynski approach by introducing the effect of the existence of strain gradient over the stretching punch. The predicted path-dependent forming limits of an anisotropic sheet were compared with the published experimental results. It was found that the predicted path-dependent forming limits were in good agreement with the experimental data.

• Journal of the Ergonomics Society of Korea
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• v.34 no.3
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• pp.217-222
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• 2015

Objective:The objective of this study is to review the exposure limits in the legislation, guidelines, and standards for human vibration in Korea. Background: There have been relatively less interests in vibration than other risk factors in Korea. However, the importance of vibration is increasing as industry and everyday life are more mechanized. Method: Various enforcements were examined including legislation, guidelines, and standards for whole-body vibration and localized vibration. Results: No exposure limits were found in legislation, guidelines, and standards for the human vibration in Korea. Conclusion: It is important to introduce new duties regarding vibration risks to the general duties. Further studies are expected on the vibration exposure limits appropriate for Korean people and job conditions. Application: The results from this study would be of help to induce more interests in human vibration to the occupational health and safety professionals of Korea.

• Journal of Arbitration Studies
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• v.23 no.3
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• pp.81-99
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• 2013

One of the most defining characteristics of arbitration is that an arbitral tribunal's jurisdiction is established by parties' mutual agreement. If a party to the arbitral proceedings believes that a tribunal constituted lacks jurisdiction to conduct the arbitral proceedings, it may challenge the jurisdiction of the tribunal in different ways. Although the concept of kompetenz-kompetenz and the grounds to challenge the Tribunal's jurisdiction are readily accepted in the arbitration community, what parties often fail to observe is the time limit imposed by the relevant laws in bringing such objections. This article aims to examine several main ways of challenging the tribunal's jurisdiction and the applicable time limits in each scenario. The article will then focus on the consequences of a party's failure to adhere to the strict time limits and its effect at the post-award stage. These issues will be considered in the light of case law from different Model law jurisdictions with particular illustrations from the arbitration law of Singapore.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.3
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• pp.136-143
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• 2010

Embedded systems widely used for wireless communication such as W-LAN, Bluetooth and ZigBee operate on ISM (Industrial, Scientific and Medical) band but they can be seriously affected by electromagnetic interference radiated from ISM apparatus. Therefore C.I.S.P.R. reports proposed limits for the protection of telecommunication from interference from ISM equipment. In this paper, we clarify the methods for calculating limits for disturbance signal for Embedded Systems in ISM band and propose simple way of calculating limits for interference signal in both above and below 1 GHz band cases.

• Journal of Korean Society for Quality Management
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• v.25 no.1
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• pp.100-115
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• 1997

Shewhart control chart is a basic technique to monitor the state of a process. We observe samples of size four or five and plot some statistic(e.g., mean or range) of each sample on the chart. When setting up the chart, we need to obtain u, pp.r and lower control limits. It is common practice that those limits are calculated from the preliminary 20-40 samples presumed to be homogeneous. However, it may ha, pp.n in practice that the samples are contaminated by outlying observations caused by various reasons. The presence of outlying observations make the control limits wider and hence decrease the sensitivity of the charts. In this paper, we introduce robust control charts with tighter control limits when outlying observations are present in the preliminary samples. Examples will be given via simulation study.

• Communications for Statistical Applications and Methods
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• v.1 no.1
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• pp.102-111
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• 1994

We Propose a method of sensitivity analysis in latent root regression analysis (LRRA). For this purpose we derive the quantities ${\beta\limits^\wedge \;_{LRR}}^{(1)}$, which correspond to the theoretical influence function $I(x, y \;;\;\beta\limits^\wedge \;_{LRR})$ for the regression coefficient ${\beta\limits^\wedge}_{LRR}$ based on LRRA. We give a numerical example for illustration and also investigate numerically the relationship between the estimated values of ${\beta\limits^\wedge \;_{LRR}}^{(1)}$ with the values of the other measures called sample influence curve(SIC) based on the recomputation for the data with a single observation deleted. We also discuss the comparision among the results of LRRA, ordinary least square regression analysis (OLSRA) and ridge regression analysis(RRA).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.8 s.239
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• pp.1139-1145
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• 2005

Most failures of ductile materials in metal forming processes occurred due to material damage evolution - void nucleation, growth and coalescence. In this paper, the modified yield function of Liao et al in conjunction with the Hosford's yield criterion is studied to clarify the plastic deformation characteristic of voided anisotropic sheet metals. The void growth of an anisotropic sheet under biaxial tensile loading and damage effect of void growth on forming limits of sheet metals are investigated. Also the characteristic length defining the neck geometry is introduced in M-K model to incorporate the effect of triaxial stress in necked region on forming limits. The forming limits theoretically predicted are compared with experimental data. Satisfactory agreement was obtained between the predictions and experimental data.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.13
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• pp.605-630
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• 2000

A letter of credit plays very important roles in rational and smooth international trade. But the parties to letter of credit transactions can bring about many troubles and losses in such transactions because of ignorance and limits of their rights and responsibilities. The purpose of this study is to analyze a legal position of confirming bank and limits of responsibilities of the confirming bank on the UCP and authoritative decisions by ICC. I attempts to analyze a legal position of confirming bank and limits of responsibilities between the confirming bank and the contract parties at the documentary credit transactions on the basis of theoretical, lawful, and international transactions.