Design and Verification of Improved Cascaded Multilevel Inverter Topology with Asymmetric DC Sources

Tarmizi Tarmizi,Soib Taib,M. K. Mat Desa 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5

This paper presents the design and implementation of an improved cascaded multilevel inverter topology with asymmetric DC sources. This experimental inverter topology is a stand-alone system with simulations and experiments performed using resistance loads. The topology uses four asymmetric binary DC sources that are independent from each other and one H-bridge. The topology was simulated using PSIM software before an actual prototype circuit was tested. The proposed topology was shown to be very efficient. It was able to generate a smooth output waveform up to 31 levels with only eight switches. The obtained simulation and experimental results are almost identical. In a 1,200W (48.3) resistive load application, the THDv and efficiency of the topology were found to be 1.7% and 97%, respectively. In inductive load applications, the THDv values were 1.1% and 1.3% for an inductive load (R=54 dan L=146mH) and a 36W fluorescent lamp load with a capacitor connected at the dc bus.

Development of an Optimal Reservoir Pumping Operation for Adaptation to Climate Change

Tarmizi Ismail,Sobri Harun,Zaitul Marlizawati Zainudin,Shamsuddin Shahid,Abu Bakar Fadzil,Usman Ullah Sheikh 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.1

Optimization of operation rule curve of Layang reservoir located in southern part of peninsular Malaysia under climate change uncertainties has been presented in this study. Downscaled climate data were incorporated in a lumped rainfall-runoff model to project daily reservoir inflow, which was then used to determine the reservoir operation rule curves to minimize the operation cost. The results reveal that climatic change will cause a rise of temperature in the range of 1.5-2.9oC, but decrease in rainfall in most of the months in the end of this century which will casue a change in the seasonal pattern of inflow to reservoir. Comparison of historical and model generated operation costs indicates that annual savings of 23% and 33% is possible with optimized reservoir operation rule curves. Assessment of the performance of the optimized operation curve under climate change scenarios shows that it will be able to cope with the changing pattern of reservoir inflow with proper adjustment. It is expected that the method presented in this paper to derive pumping operation curves to optimize the total volume of water to be pumped from various sources to reservoir can be useful for reservoir operators in the context of climate change.

Flax Fiber Composite with Core-Shell Nanofiber Interlayer as Toughening and Healing Agent

Mohamad Tarmizie Hassim,M.N. Prabhakar,Dong Woo Lee,Jung-Il Song 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.6

Empirical analysis on port state control inspection for foreign-registered ships in Malaysian ports

Osman Mohd Tarmizi,Tian Li,Yuli Chen,Abdul Rahman Noorul Shaiful Fitri 한국해운물류학회 2021 The Asian journal of shipping and Logistics Vol.37 No.2

The selection of foreign-registered ships upon entering ports poses challenges to maritime authorities in ensuring the effectiveness of the port state control (PSC) inspection. The derived data from the ships’ arrival notification system has been utilised in this study to identify the preferred vessel type for inspection. A combination of the Grey Relational Analysis (GRA) model and Entropy Weight Method (EWM) has been applied to discern the various types of ships that entered five selected ports in Malaysia and disclose the propensity of each vessel type. Based on 100,623 ship arrival records obtained for a period of five years (2015–2019), the types of ships were identified, analysed, scored, and graded. The result shows that the oil tanker has the highest value of grey relational grade for Bintulu port while the passenger ship is in the pole position for Penang port. Kuching port and Port Kelang share the container type as the first in the ranking, whereas Lahad Datu posted the oil tanker. Other results include the sequence of types at individual ports for providing useful information to help policymakers in establishing an effective inspection design. A similar approach is applicable in PSC inspection records for further analysis.

Distributional Changes in Rainfall and River Flow in Sarawak, Malaysia

Zulfaqar Sa’adi,Shamsuddin Shahid,Tarmizi Ismail,정은성,Xiao-Jun Wang 한국기상학회 2017 Asia-Pacific Journal of Atmospheric Sciences Vol.53 No.4

Climate change may not change the rainfall mean, but the variability and extremes. Therefore, it is required to explore the possible distributional changes of rainfall characteristics over time. The objective of present study is to assess the distributional changes in annual and northeast monsoon rainfall (November-January) and river flow in Sarawak where small changes in rainfall or river flow variability/distribution may have severe implications on ecology and agriculture. A quantile regression-based approach was used to assess the changes of scale and location of empirical probability density function over the period 1980-2014 at 31 observational stations. The results indicate that diverse variation patterns exist at all stations for annual rainfall but mainly increasing quantile trend at the lowers, and higher quantiles for the month of January and December. The significant increase in annual rainfall is found mostly in the north and central-coastal region and monsoon month rainfalls in the interior and north of Sarawak. Trends in river flow data show that changes in rainfall distribution have affected higher quantiles of river flow in monsoon months at some of the basins and therefore more flooding. The study reveals that quantile trend can provide more information of rainfall change which may be useful for climate change mitigation and adaptation planning.

Measurement Instruments for Superior Product Development: A Case Study of Deli Serdang Cassava in Indonesia

Remus Hasiholan P,Hasan Basri TARMIZI,Rahmanta RAHMANTA,Agus PURWOKO 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.5

This study is aimed at developing a measurement instrument for the superior product development program of Deli Serdang cassava, Indonesia. This research population is the target population of Deli Serdang Micro, Small and Medium-sized Enterprises (MSMEs) which produces cassava. The sample was randomly selected and consisted of 300 MSMEs. The study method is research and development with confirmatory factor analysis using Amos software. The data collection technique was a questionnaire. Study results used the maximum likelihood method which showed that the validity and reliability instruments met the ideal loading factor value > 0.5 and a significance value of p (0.000). The model built also meets the fit criteria based on the Goodness of Fit Model Standard. All instruments are presented to build and measure the superior cassava product development program by Deli Serdang MSMEs. This superior product development program comprises (1) economic contribution (with a loading factor value of 0.76) (2) social aspects (with a loading factor value of 0.76) (3) cultural aspects (with a loading factor value of 0.99) and (4) institutional (with a loading factor value of 0.87). This result means that all instruments have proven construct validity.

Characteristics of Annual and Seasonal Trends of Rainfall and Temperature in Iraq

Saleem A. Salman,Shamsuddin Shahid,Tarmizi Ismail,Kamal Ahmed,Eun-Sung Chung,Xiao-Jun Wang 한국기상학회 2019 Asia-Pacific Journal of Atmospheric Sciences Vol.55 No.3

Changes in the temperature and precipitation have significantly affected water resources and agricultural productions in many countries across the world. The objective of the present study is to analyze the changing patterns of annual and seasonal precipitation and temperature in Iraq for the period 1961–2010. Monthly gridded precipitation and temperature data of Global precipitation climate center (GPCC) and climate research unit (CRU) respectively having a spatial resolution of 0.5° were used in this study to show the spatial pattern in trends. The rate of change in rainfall and temperature was estimated using Sen’s slope method while the significance of change was confirmed using Mann-Kendal test (MK) and the modified Mann-Kendall test (mMK). The results revealed large differences in the number of grid points showing significant changes in rainfall and temperature using MK and mMK methods. The mMK method revealed that the annual rainfall is decreasing at a rate of −1.0 to −5.0 mm/year in the northwest part of Iraq. The seasonal precipitations were found to decrease in spring (−0.4 to −2.56 mm/ year) and winter (−0.4 to −2.0 mm/year), increase in summer (0.06 to 0.21 mm/year) at a few grid points and no change in autumn. On the other hand, a sharp rise in annual average of daily mean (0.42 to 0.64 °C/decade), maximum (0.39 to 0.65 °C/ decade) and minimum (0.36 to 0.69 °C/decade) temperature was observed.

The Role of Government Regulations in Enhancing Corporate Social Responsibility Disclosure and Firm Value

FAISAL, Faisal,SITUMORANG, Lilis Suryani,ACHMAD, Tarmizi,PRASTIWI, Andri Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.8

This study investigates, first, whether the extent of corporate social and environmental responsibility disclosure (CSERD) differs between 2010 and 2014; second, whether government regulation affects the extent of CSERD; and, third, whether the CSERD is valued by investors. Content analysis method was used to extract 466 companies' annual reports to measure the extent of social and environmental responsibility disclosure based on the Global Reporting Initiative (GRI) checklist. Independent sample t-test and multivariate regression analysis were also conducted to test the differences of the extent of CSERD as well as determinants and consequence of CSERD. Our results show that the extent of CSERD in 2014 is 21.60 percent higher than in 2010 (13.39 percent). Government regulation has a significant effect on the extent of CSERD. This study also finds that market values positively CSER information disclosed by company. Given that government regulation has a positive impact, however, the findings of this study suggests that the extent of CSERD is still low. To enhance CSERD, government should continuously encourage companies to abide by the regulations as mandated. This study provides a more comprehensive insights of CSRED practices from an emerging country and the effect of government regulation in enhancing CSERD.

A randomized, double-blind study comparing multiple doses of Channa striatus supplementation for knee osteoarthritis

Abdul Kadir Azidah,Abdul Kadir Arifah,A. H. Roslida,Abdul Manan Mat Jais,Julia Omar,Abdul Nawfar Sadagatullah,Azlina Ishak,Norhayati Mohd. Noor,Ahmad Tarmizi Musa 경희대학교 융합한의과학연구소 2017 Oriental Pharmacy and Experimental Medicine Vol.17 No.4

Knee osteoarthritis (OA) is the leading cause of chronic disability at older age. Channa striatus (CS) is a freshwater fish that is traditionally valued for its medicinal properties in promoting wound healing and reducing post-operative pain. This study evaluate the efficacy of different doses of oral Channa striatus extract on primary knee osteoarthritis patients. A randomized, double-blind, placebo-controlled 3-arm trial was conducted comparing oral CS extract 1000 mg/day or 500 mg/day and placebo among knee OA patients for a 6-month intervention period. The main outcome measures were Western Ontario and McMaster University Osteoarthritis Index (WOMAC), analgesic scores and serum cartilage oligomeric matric protein (COMP). Laboratory-based blood tests were used as safety measures. A total of 120 patients were randomized, and 112 patients were included in the intention-to-treat analysis. Significant reductions in WOMAC stiffness and function scores were achieved at month 6 in CS 1000 mg/day and CS 500 mg/day compared to placebo groups (p < 0.05). No significant differences were found between the groups in terms of analgesic scores, serum COMP and biochemical parameters. No serious adverse events were reported in the study. In conclusion, both doses of CS showed similar efficacy and were more effective than the placebo in treating the symptoms of knee OA.