A SIMULATION STUDY ON DISPATCHING RULES FOR OVERHEAD SHUTTLES IN AN AUTOMATED CONTAINER TERMINAL

Sofyan Dwi Cahyo,Jeong Hwan Kim(김정환),Kap Hwan Kim(김갑환),Soondo Hong(홍순도) 대한산업공학회 2016 대한산업공학회 춘계학술대회논문집 Vol.2016 No.4

Dispatching Rules and Dwelling Strategies for Overhead Shuttles in an Automated Container Terminal

Sofyan Dwi Cahyo,Jeong Hwan Kim,Kap Hwan Kim,Soondo Hong 대한산업공학회 2015 대한산업공학회 추계학술대회논문집 Vol.2015 No.11

This study investigates dispatching rules and dwelling strategies that optimize the waiting time of flatcars (FCs) in automated container terminals. We consider a terminal with two overhead shuttles (OSs) in the same line and the FCs wait for the OSs at specified transfer points (TPs). We also include a scenario when more than one FC arrives at the same OS’s TPs. We conclude that combining the shortest processing time (SPT) rule of the OS dispatching rules with an appropriate dwelling strategy will improve operational efficiency and reduce the waiting time of flatcars in automated container terminals.

Microgravity method to model mass balance in the Kamojang Geothermal Field

Yayan Sofyan,Yunus Daud,Yustin Kamah,Sachio Ehara 한국물리학회 2010 Current Applied Physics Vol.10 No.2

Indonesia has the largest geothermal resource potential in the world, with total energy potential about 27.5 GWe. Kamojang Geothermal Field is the oldest geothermal field in Indonesia. More than 116.78 × 106 ton of steam has been exploited from the Kamojang Geothermal Field between 1983 and 2000. Today, the production decline problem at the Kamojang Geothermal Field needs to be solved by reservoir management. Reservoir management is used to solve and to maintain the stability of the steam production which is influenced by reservoir mass balance. The periodic changes of reservoir condition can be measured by the microgravity method. Between 1999 and 2005, microgravity method was used in The Kamojang Field to measure the changes of the gravity values with 51 gravity benchmarks. Mass changes in the geothermal reservoir were calculated in the same period based on Gauss theory. The interpretation of the microgravity data at Kamojang Geothermal Field shows the mass balance model in the reservoir. In six years production period, the microgravity method indicated that Kamojang Geothermal Field has a mass decrease of about 3.34 Mt/year and 2.73 Mt/year is estimated as the natural recharge. It is very important to balance the mass to continue sustainable production.

The Influence of Transformational Leadership on Organizational Performance: A Case Study in Indonesia

EFFIYANTI, Effiyanti,LUBIS, Abdul Rahman,SOFYAN, Sofyan,SYAFRUDDIN, Syafruddin Korea Distribution Science Association 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.2

The purpose of this study was to examine the relationship between transformational leadership and organizational performance with readiness to change and empower knowledge sharing quality as mediating variables. The survey was conducted by collecting the respondents' data by filling up forms which were designed using the google form application and collecting it using WhatsApp. This was performed on 400 respondents, encompassing employees from the National Agency of Drug and Food Control in Indonesia. The research model adopted was validated using Structural Equation Modeling technique with AMOS tool. The findings showed transformational leadership as a significant predictor of readiness to change and it proved relevant in empowering knowledge sharing quality, which in turn affects organizational performance. Furthermore, the effects of both two mediating variables was also examined, and only readiness to change significantly influenced the relationship between predictors of transformational leadership and organizational performance. The findings of this study showed the need for transformational leaders as the research focused on understanding the differences in employee character. This is required to encourage better performance by empowering quality knowledge dissemination mechanisms, with continuous in-house training activities. Therefore, the model adopted in this research and the hypotheses prove the direct effect of transformational leadership on organizational performance, achievable through the mediating role of readiness to change.

Distribution of Advertisement on Instagram in Relation to Satisfaction and Loyalty of Low-Cost Airline Passengers in Indonesia

Fatimah Febriyanti BASTARI(Fatimah Febriyanti BASTARI ),M. ARAS(M. ARAS ),Cici Fakhrunnisa SOFYAN(Cici Fakhrunnisa SOFYAN ),Taniya Indriana RUSTAM(Taniya Indriana RUSTAM ) 한국유통과학회 2023 유통과학연구 Vol.21 No.3

Purpose: Low-Cost Carrier airlines attempt to provide the best service for their customers. However, the pandemic has forced airline companies to keep developing new strategies. Moreover, in this digital era, airlines must intensely market their service through social media to reach as many customers as possible. This research aims to study the impact of advertisements on Instagram and the customer experience concerning customer loyalty and satisfaction in the aviation industry. Research design, data, and methodology: This study uses a quantitative explanatory with the combination of the positivism paradigm. The data collection technique is by distributing questionnaires to related airline Instagram followers. Meanwhile, the sample calculation uses using the Slovin formula in which 414 respondents are gained. The collected data is analyzed with Structural Equation Model and using Smart-PLS software. Results: The study results indicate that advertising on Instagram and customer experience significantly positively affect customer satisfaction and loyalty. In addition, the variable customer satisfaction has a significant positive on customer loyalty. Conclusions: The study results indicate that the ease of obtaining information via Instagram can affect satisfaction and will increase when customers have made a flight so that they will become loyal customers.

점진적 구역 집하 시스템 내 재고 보충 작업에 따른 집하지연 평가를 위한 시뮬레이션 연구

한광욱,Sofyan Dwi Cahyo,홍순도 한국SCM학회 2023 한국SCM학회지 Vol.23 No.3

Since the growth of the e-commerce market necessitates prompt order processing in order picking systems (OPSs), flow-rack zone picking systems have been widely implemented. In the systems, inventory shortage is a significant factor in order picking productivity, i.e., picker idleness and shortage delay. To deal with these productivity losses, the systems can employ an automated storage and retrieval crane (S/R crane) to replenish items for flow-racks from the reserved-racks. In this study, we conducted a comprehensive simulation analysis to identify the impacts of shortage delay on productivity in various OPS configurations. The simulation experiments confirm that: (1) the impact of shortage delay varies with different S/R crane performance, ratios of picking and travel times, order inter-arrival times, replenishment quantities, and storage assignment policies; (2) the amount of shortage delay in each zone has been decreased from the center to the edges; and (3) the central rack in each zone shows the least amount of shortage delay compared to other racks.

Relationships between dietary rumen-protected lysine and methionine with the lactational performance of dairy cows — A meta-analysis

Irawan Agung,Sofyan Ahmad,Wahyono Teguh,Harahap Muhammad Ainsyar,Febrisiantosa Andi,Sakti Awistaros Angger,Herdian Hendra,Jayanegara Anuraga 아세아·태평양축산학회 2023 Animal Bioscience Vol.36 No.11

Objective: Our objective was to examine the relationships of supplemental rumen-protected lysine (RPL) or lysine + methionine (RPLM) on lactational performance, plasma amino acids (AA) concentration, and nitrogen use efficiency of lactating dairy cows by using a meta-analysis approach. Methods: A total of 56 articles comprising 77 experiments with either RPL or RPLM supplementation were selected and analyzed using a mixed model methodology by considering the treatments and other potential covariates as fixed effects and different experiments as random effects. Results: In early lactating cows, milk yield was linearly increased by RPL (β1 = 0.013; p< 0.001) and RPLM (β1 = 0.014; p<0.028) but 3.5% fat-corrected milk (FCM) and energycorrected milk (ECM) (kg/d) was increased by only RPL. RPL and RPLM did not affect dry matter intake (DMI) but positively increased (p<0.05) dairy efficiency (Milk yield/DMI and ECM/DMI). As a percentage, milk fat, protein, and lactose were unchanged by RPL or RPLM but the yield of all components was increased (p<0.05) by feeding RPL while only milk protein was increased by feeding RPLM. Plasma Lys concentration was linearly increased (p<0.05) with increasing supplemental RPL while plasma Met increased (p<0.05) by RPLM supplementation. The increase in plasma Lys had a strong linear relationship (R2 = 0.693 in the RPL dataset and R2 = 0.769 in the RPLM dataset) on milk protein synthesis (g/d) during early lactation. Nitrogen metabolism parameters were not affected by feeding RPL or RPLM, either top-dress or when supplemented to deficient diets. Lactation performance did not differ between AA-deficient or AA-adequate diets in response to RPL or RPLM supplementation. Conclusion: RPL or RPLM showed a positive linear relationship on the lactational performance of dairy cows whereas greater improvement effects were observed during early lactation. Supplementing RPL or RPLM is recommended on deficient-AA diet but not on adequate-AA diet.

Web-Based Instructional Media and Students’ Writing Skills in Learning Indonesian Language

Mujiono Wiryotinoyo,Sofyan,Sudaryano APEC국제교육협력원 2016 Asia-Pacific Cybereducation Journal Vol.12 No.2

This research is aimed at developing Web-Based Instructional Media in the Indonesian senior high school writing class. The Dick and Carey Model (2009) was employed as the development model. The steps began with identifying instructional goals, conducting instructional analysis, analyzing learners and contexs, writing the performance objectives, developing assessment instruments and instructional strategies, developing and selecting instructional materials, designing and conducting formative evaluation of instruction, revising, and finally designing and conducting summative evaluation. The overall results identified that the Educational Technology Expert validation reached 94.62%, the Media Expert reached 99.04%, and the Matter Expert reached 85.00%. These results proved that the use of Web-Based Instructional Media significantly improved the students’ writing skills. The small group trial demonstrated 78.38%, while the field trial 82.79%; these showed that the Web-Based Instructional Media could be implemented both in the small group and the field trial. In conclusion, the results of the expert validation and the field trials stated that the web-based instructional media is highly appropriate use in improving Bahasa Indonesian students writing skills.

Maladaptive Behavior and Gastrointestinal Disorders in Children with Autism Spectrum Disorder

Pusponegoro, Hardiono D.,Ismael, Sofyan,Sastroasmoro, Sudigdo,Firmansyah, Agus,Vandenplas, Yvan The Korean Society of Pediatric Gastroenterology 2015 Pediatric gastroenterology, hepatology & nutrition Vol.18 No.4

Purpose: Various gastrointestinal factors may contribute to maladaptive behavior in children with autism spectrum disorders (ASD). To determine the association between maladaptive behavior in children with ASD and gastrointestinal symptoms such as severity, intestinal microbiota, inflammation, enterocyte damage, permeability and absorption of opioid peptides. Methods: This observational cross-sectional study compared children with ASD to healthy controls, aged 2-10 years. Maladaptive behavior was classified using the Approach Withdrawal Problems Composite subtest of the Pervasive Developmental Disorder Behavior Inventory. Dependent variables were gastrointestinal symptom severity index, fecal calprotectin, urinary D-lactate, urinary lactulose/mannitol excretion, urinary intestinal fatty acids binding protein (I-FABP) and urinary opioid peptide excretion. Results: We did not find a significant difference between children with ASD with severe or mild maladaptive behavior and control subjects for gastrointestinal symptoms, fecal calprotectin, urinary D-lactate, and lactulose/mannitol ratio. Urinary opioid peptide excretion was absent in all children. Children with ASD with severe maladaptive behavior showed significantly higher urinary I-FABP levels compared to those with mild maladaptive behavior (p=0.019) and controls (p=0.015). Conclusion: In our series, maladaptive behavior in ASD children was not associated with gastrointestinal symptoms, intestinal inflammation (no difference in calprotectin), microbiota (no difference in urinary D-lactate) and intestinal permeability (no difference in lactulose/manitol ratio). ASD children with severe maladaptive behavior have significantly more enterocyte damage (increased urinary I-FABP) than ASD children with mild maladaptive behavior and normal children.

The Short-run and Long-run Dynamics Between Liquidity and Real Output Growth: An Empirical Study in Indonesia

Sapto JUMONO,Joel Faruk SOFYAN,Sugiyanto SUGIYANTO,Chajar Matari Fath MALA 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.5

The objectives of this research are to see if the phenomena of “demand following” and “supply leading” exist in the business cycle, as well as to look at how liquidity and output react to changes in credit risk, investment-saving gap, inflation, exchange rate, and growth rate of real national output. Employing quarterly data of Maluku and North Maluku (2008–2019), this study utilizes VAR/VECM for inferential analysis. This research found three important findings. First, liquidity and output growth influenced each other in the long run. Second, the determinants of output growth for Maluku are liquidity, investment-saving gap, and inflation, while the determinants of liquidity are output-growth, the gap of investment-saving, and inflation. Third, the determinants of output growth for North Maluku are liquidity, credit risk, investment-saving gap, inflation, exchange rate, and the national output-growth, while the determinants of liquidity are output-growth, credit risk, investment-saving gap, inflation, exchange rate, and national output-growth. The findings of this study supported the hypothesis of demand following and supply leading theory in the Maluku and North Maluku business cycles. This study concludes that economic development would improve if supported by liquidity adequacy through increased deposit growth.