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This study examines the forecasting ability of the adjusted implied volatility (AIV), which is suggested by Kang, Kim and Yoon (2009), using the horserace competition with historical volatility, model-free implied volatility, and BS implied volatility in the KOSPI 200 index options market. The adjusted implied volatility is applicable when investors are not risk averse or when underlying returns do not follow a normal distribution. This implies that AIV is consistent with the presence of risk premia for other risk such as volatility risk and jump risk. Using KOSPI 200 index options, it is shown that the AIV outperforms other volatility estimates in terms of the unbiasedness for future realized volatilities as well as the forecasting errors.

The study objective was to investigate the microbial status of the coffee, ice and cups used in coffee outlets. This study compared food safety practices and microbial status between franchised and single-unit outlets.

The study subjects included franchised and single-unit coffee outlets. This study adopted two different methods: self-answered checklists and microbial laboratory tests. We compared the two datasets by operation type (franchised vs single-unit). We analysed the data using independent t-test and chi-square tests.

Franchised outlets were more likely to apply food safety practices than single-unit outlets; however, microbial testing showed that franchised outlets had a worse microbial status than single-unit outlets. A restaurant sanitation certificate did not influence microbial status. In addition, an analysis of food safety practice checklist items and microbial status showed that the checklist items did not impact food safety.

These study results suggest that regular employee training programmes are needed for food safety and sanitation. Current inspection items should be revised and new items added for target operations (outlets that make and serve beverages). The current restaurant certification system should be revised, and certified food service outlets should be inspected regularly.