• IE interfaces
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• v.15 no.1
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• pp.64-72
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• 2002

Broaching machine is widely used for machining inner shaped slots in the work-pieces, and provides vertical motion (usually hydraulically powered) between tool and work-piece. In this study, we modelled the tool life process and investigated economic tool life of broaching machine. Tool life process is divided into wear-process and succeeding failure process. Wear process is defined as machining wear and failure process as 'chipping' occurred by random shock. We modelled wear process as linear regression function for products amounts and assumed failure process as Poisson process. Economic tool life is defined as the number of lots which minimizes average tool related cost per lot and analyzed by using age replacement policy technique. As tool-related cost factors, we consider tool replacement cost, tool maintenance cost and quality costs of products. The results of this study can be applied to analyze life process of general machining tools.

• Journal of Korean Society for Quality Management
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• v.52 no.2
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• pp.287-301
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• 2024

Purpose: This paper aims to verify the difference in production resilience between local clusters and regions without clusters before and after a major crisis. Furthermore, this paper aims to identify the clusters' quality factors that impact clusters' shock vulnerability and resilience. Methods: Utilizing open-source data from the US Cluster Mapping platform, this paper compares regions with industrial clusters to those without using the Differences-in-Differences (DID) estimator. It considers the regions with industrial clusters as a treatment group and others as the control group, comparing the period before and after the pandemic. Additionally, the paper examines which cluster factors make a difference in economic resilience during the crisis using Regression Discontinuity Design (RDD). Results: The study finds that regions with industrial clusters show higher production resilience compared to regions without clusters. Moreover, the number of establishments, annual payrolls, and employment can have a positive impact on resilience during the pandemic shock. Conclusion: Though clusters could be vulnerable during the global crisis, industrial clusters can contribute to regional economic development and production resilience in the long-term aspect. Thus, it is required to construct a high-quality local cluster and support it during the economic crisis in the long-term aspect.

• KDI Journal of Economic Policy
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• v.32 no.3
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• pp.1-32
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• 2010

The global financial crisis has exerted enormous impacts on the attainment of inflation target in Korea. The annual average CPI inflation was 3.3% during the targeting period of 2007-2009 and the target was $3.0{\pm}0.5%$. Thus Korea has succeeded in keeping annual average CPI inflation just below the upper limit of the 2007-2009 target under the global crisis. This paper intends to evaluate the performance of the inflation targeting system in Korea. First, it estimates the conventional call rate reaction equation under the global crisis and finds that the policy interest rates never reacted to expected inflation, output gap, and won/dollar exchange rate, as expected by theory. Second, it identifies the shock of global financial crisis into core and non-core, applying the structural VAR model. The core shock was defined to have no (medium- to) long-run impact on real output. The core shock was identified to have the character of the demand shock, since it has the positive impact on the inflation and output in the short run. The structural core inflation due to core shock was an attractor of headline inflation, not vice versa. Therefore, the structural core inflation that reflects the demand-side shock would be the better intermediate target for the final headline inflation target than the official core inflation that excludes the volatile inflation of agricultural and oil-related products. During the inflation targeting period of 2007-2009, the structural core inflation was more volatile than the official core inflation, because the global crisis has very large negative impacts on the domestic demand as well as the prices of agricultural and oil-related products. This paper shows that the negative core shock during the fourth quarter of 2008 was larger than that in the financial crisis in 1998. But the core shock turned into positive very quickly in 2009, as the Korean economy recovered very quickly from crisis. The volatile changes in structural core inflation suggests that the Bank of Korea barely managed to attain the 2007-2009 inflation target, owing to the very large negative impacts of the global financial crisis on the domestic demand. It also suggests that the rapid rise in core inflation with the rapid recovery of the Korean economy will lead to rapid rise in headline inflation.

• Korean System Dynamics Review
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• v.10 no.3
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• pp.47-79
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• 2009

The paper examines dynamic relationship among 'Limit to Growth' factors in Korea using causal loop diagram. It also aims to explore policy implications for Korea in overcoming current difficulties and future crisis we may face. For this purpose, five factors -economy, population, resource, environment, food- used in the were adopted as an analytical framework. Findings show that Korea is fragile to external shock such as world economic crisis, food price surge, and resource price -including energy price- hike. High dependency of energy, food and resource on foreign market was found to be a major source of limit to growth in Korea. Furthermore, environmental problems like global warming could be a major external shock that could hit Korea harder than the rest of the world. Policy implications and measures for these problems were discussed too.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.6
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• pp.1109-1113
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• 2010

Recently, important for the safety has been increasing together economic developments. The leakage only is measured by the voltage difference. This method is a way to contact the electric leakage area. It can cause electric shock at users. We propose a non-contact method to detect a short circuit in this paper. We investigate magnetic field at electric leakage area to present non-contact method. Simulated environment created a short circuit in the flooded areas. Voltage is supplied 50, 150 and 200[V]. Magnetic field was measured at 0, 5 and 10[cm]. Magnetic flux was reduced about $0.4[{\mu}T/cm]$ depending on the distance changes in the steady region. But we confirmed that magnetic flux is measured the same value depending on the distance changes in the electric leakage area.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.1
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• pp.100-103
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• 2003

Higher environmental temperature affects the economic performance of pigs. Heat shock protein 70 has been shown to play an important role in thermoresistance. The purpose of this study was to assess the effect of a single nucleotide polymorphism in the 5'-flanking region of porcine HSP70.2 on growth performance in Taiwanese Duroc. The genotype of this nt 393 polymorphic site could be verified by digestion with Bsa WI restriction enzyme of a PCR product. Pigs with TT and TC genotypes have thinner backfats than those with CC type (p<0.05). The result suggested that the polymorphic Bsa WI site in the 5'flanking region of porcine HSP70.2 may be used as a marker for the early selection of ultrasonic backfat thickness in Duroc pigs.

• KDI Journal of Economic Policy
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• v.43 no.1
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• pp.29-52
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• 2021

The purpose of this paper is to measure the impact of the recent Korea-Japan trade dispute on the Korean economy using supply-driven input-output analysis. In July 2019, Japan announced the decision to tighten the export control of three materials which are indispensable in the manufacturing of semiconductors and electronic display panels. Japan's decision directly affects production in Korea's semiconductor and display sectors and is hence not a demand shock. For this reason, a standard demand-driven input-output analysis is not valid despite the fact that it can still be applied. The impact of Japan's decision on Korea's aggregate and individual sectors' gross output, GDP and employment were computed using both methods.

• KDI Journal of Economic Policy
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• v.42 no.4
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• pp.59-90
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• 2020

U.S. monetary policy has been claimed to generate global spillover and to destabilize other small open economies. We analyze the effects of certain identified U.S. monetary shocks on gross capital flows in the Korean economy using the local projection method. Consistent with previous results on other small open economies, we initially confirm that U.S. interest rate hikes are dynamically correlated with foreign outflows and residents' inflows. That is, not only are they correlated with withdrawals by foreigners but they are also correlated with those by domestic (Korean) investors. The results are mostly driven by portfolio flows. Second, however, the marginal response to a U.S. monetary policy shock is, on average, subdued if we focus on the sample periods after the Global financial crisis of 2007-2008 (henceforth, global financial crisis). We conjecture a possible reason behind the change, an institutional change related to financial friction. If the degree of pledgeability of the value of net worth increases, the marginal responses by both investors would drop with a U.S. monetary policy shock, consistent with our findings.

• Journal of Korea Trade
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• v.24 no.4
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• pp.1-17
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• 2020

Purpose - Since China has been South Korea's biggest export destination, uncertainty shocks originating from it would influence South Korea's exports. This paper evaluates the effects of China's economic policy uncertainty on Korea's exports to explore the transmission channels. Design/methodology - Incorporating endogeneities and nonlinearities, this study employs a quarterly time-varying parameters vector autoregressive model to investigate the relationships between China's economic policy uncertainty and Korea's exports, where the overparameterization due to time-varying specifications is overcome by a novel stochastic model specification search framework. According to previous theoretical studies, this paper assesses two channels, demand shock channel and exchange rate channel, through which foreign uncertainty affects Korea's exports. This paper identifies the primary drivers of Korea's aggregate exports and analyzes the rationales for the time-variant impacts of China's economic policy uncertainty on Korea's exports to China. Findings - Our empirical results reveal that Korea's aggregate exports are less responsive to China's economic policy uncertainty shocks and significantly move together with global demand. In contrast, its bilateral exports to China are highly responsive in a negative and time-variant way. Moreover, Chinese investment is an important channel through which China's economic policy uncertainty affects Korea's exports to China after 2010. Further, the time-variant effects of China's economic policy uncertainty on Korea's exports to China are related to changes in China's foreign trade policies, global economic conditions, and China's degree of economic freedom. Originality/value - Few previous studies touch the effects of external uncertainty shocks on South Korea's exports. This paper attempts to fill this gap and explicitly investigate the impacts of China's economic policy uncertainty on Korea's exports from a time-varying perspective. As Korea is an export-oriented economy, this study provides insights for the Korean government to understand the transmissions of external uncertainty better.

• Journal of Korea Port Economic Association
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• v.27 no.1
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• pp.1-11
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• 2011

The main purpose of this paper is to estimate the impact of exchange rate and economic business activity on the passengers' demand for international transportation. The demand pattern depends upon the transport vehicles that the global passengers take. The global passengers' demand for transportation is modelled as exchange rate, industrial production and seasonal dummy variables. The seasonality is found in both water and air, but the former is far greater than the latter. All series span the period January 1990 to December 2008. The empirical results of this paper reveal that the income elasticity of sea transport is greater than that of air one, all of which are positive. The study also shows that the exchange rate has an significant impact on the demand for air transport, whereas it is insignificant in water transport. The impulse response function indicates that passengers increase steadily before peaking seven to eight months after the shocks to economic business activity and decline very slowly to its pre-shock level. The air passengers also respond negatively to the shocks in exchange rate and the impacts of exchange rate shock seem to decrease relatively slowly, while the water passengers respond positively after six months. The industrial production shocks remain above equilibrium for more than twenty four months, while the exchange rate shocks remain below equilibrium for more than twenty four months. Boosted by improved economic conditions worldwide, international tourism has recovered faster than expected from the impacts of the global financial crisis and economic recession of late 2008 and 2009. These facts suggest that the demand of global water transport has the high possibility of growing steadily and continuously.